Compare dump()s instead of json values in the BJData fuzzer's round-trip check

The value-stability assertion added to fix the earlier OSS-Fuzz crash (json::from_bjdata(to_bjdata(j2)) == j2) itself broke on a NaN payload: IEEE 754 NaN is never equal to itself, so operator== reports two structurally-identical trees containing a non-finite double as different -- not a round-trip bug, just NaN's ordinary non-reflexivity. dump() serializes any non-finite double the same deterministic way (as JSON null, since JSON cannot represent NaN or Infinity), so comparing dumps is stable under exactly the values that break operator==. Verified against both the original OSS-Fuzz crash input and the new one (0x68 0x68 0x7c, which decodes to a NaN), plus a local 2.5M-case random-input sweep with no failures. Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Relax the BJData fuzzer's round-trip check from byte-exact to value-exact
2026-09-09 09:47:58 +00:00 · 2026-09-09 10:21:29 +02:00 · 2026-09-09 10:21:29 +02:00 · 2026-09-09 10:21:29 +02:00 · 2026-09-09 10:21:29 +02:00 · 2026-09-09 10:21:28 +02:00
98 changed files with 2581 additions and 2913 deletions
@@ -11,7 +11,7 @@ jobs:
    runs-on: ubuntu-latest
    steps:
      - name: Harden Runner
-        uses: step-security/harden-runner@05e31511f85b41b11d1cf0ef85d0992719546e2c # v2.21.0
+        uses: step-security/harden-runner@e14015d583714f6e62063499dc959a02595150a1 # v2.21.1
        with:
          egress-policy: audit

@@ -34,7 +34,7 @@ jobs:

    steps:
      - name: Harden Runner
-        uses: step-security/harden-runner@05e31511f85b41b11d1cf0ef85d0992719546e2c # v2.21.0
+        uses: step-security/harden-runner@e14015d583714f6e62063499dc959a02595150a1 # v2.21.1
        with:
          egress-policy: audit

@@ -9,7 +9,7 @@ jobs:
    runs-on: ubuntu-22.04
    steps:
    - name: Harden Runner
-      uses: step-security/harden-runner@05e31511f85b41b11d1cf0ef85d0992719546e2c # v2.21.0
+      uses: step-security/harden-runner@e14015d583714f6e62063499dc959a02595150a1 # v2.21.1
      with:
        egress-policy: audit

@@ -27,7 +27,7 @@ jobs:

    steps:
    - name: Harden Runner
-      uses: step-security/harden-runner@05e31511f85b41b11d1cf0ef85d0992719546e2c # v2.21.0
+      uses: step-security/harden-runner@e14015d583714f6e62063499dc959a02595150a1 # v2.21.1
      with:
        egress-policy: audit

@@ -38,14 +38,14 @@ jobs:

    # Initializes the CodeQL tools for scanning.
    - name: Initialize CodeQL
-      uses: github/codeql-action/init@ff2f1c621b7f889edc0d3c761ac2e6a3f8cdb0dd # v4.37.7
+      uses: github/codeql-action/init@cdf488f595d80d6e07e03d4674febd5ab45fa938 # v4.37.9
      with:
        languages: c-cpp

    # Autobuild attempts to build any compiled languages  (C/C++, C#, or Java).
    # If this step fails, then you should remove it and run the build manually (see below)
    - name: Autobuild
-      uses: github/codeql-action/autobuild@ff2f1c621b7f889edc0d3c761ac2e6a3f8cdb0dd # v4.37.7
+      uses: github/codeql-action/autobuild@cdf488f595d80d6e07e03d4674febd5ab45fa938 # v4.37.9

    - name: Perform CodeQL Analysis
-      uses: github/codeql-action/analyze@ff2f1c621b7f889edc0d3c761ac2e6a3f8cdb0dd # v4.37.7
+      uses: github/codeql-action/analyze@cdf488f595d80d6e07e03d4674febd5ab45fa938 # v4.37.9
@@ -19,7 +19,7 @@ jobs:
      pull-requests: write
    steps:
      - name: Harden Runner
-        uses: step-security/harden-runner@05e31511f85b41b11d1cf0ef85d0992719546e2c # v2.21.0
+        uses: step-security/harden-runner@e14015d583714f6e62063499dc959a02595150a1 # v2.21.1
        with:
          egress-policy: audit

@@ -17,7 +17,7 @@ jobs:
    runs-on: ubuntu-latest
    steps:
      - name: Harden Runner
-        uses: step-security/harden-runner@05e31511f85b41b11d1cf0ef85d0992719546e2c # v2.21.0
+        uses: step-security/harden-runner@e14015d583714f6e62063499dc959a02595150a1 # v2.21.1
        with:
          egress-policy: audit

@@ -27,7 +27,7 @@ jobs:
      security-events: write
    steps:
      - name: Harden Runner
-        uses: step-security/harden-runner@05e31511f85b41b11d1cf0ef85d0992719546e2c # v2.21.0
+        uses: step-security/harden-runner@e14015d583714f6e62063499dc959a02595150a1 # v2.21.1
        with:
          egress-policy: audit

@@ -43,6 +43,6 @@ jobs:
          output: 'flawfinder_results.sarif'

      - name: Upload analysis results to GitHub Security tab
-        uses: github/codeql-action/upload-sarif@ff2f1c621b7f889edc0d3c761ac2e6a3f8cdb0dd # v4.37.7
+        uses: github/codeql-action/upload-sarif@cdf488f595d80d6e07e03d4674febd5ab45fa938 # v4.37.9
        with:
          sarif_file: ${{github.workspace}}/flawfinder_results.sarif
@@ -17,7 +17,7 @@ jobs:

    steps:
      - name: Harden Runner
-        uses: step-security/harden-runner@05e31511f85b41b11d1cf0ef85d0992719546e2c # v2.21.0
+        uses: step-security/harden-runner@e14015d583714f6e62063499dc959a02595150a1 # v2.21.1
        with:
          egress-policy: audit

@@ -26,7 +26,7 @@ jobs:
    runs-on: ubuntu-22.04
    steps:
      - name: Harden Runner
-        uses: step-security/harden-runner@05e31511f85b41b11d1cf0ef85d0992719546e2c # v2.21.0
+        uses: step-security/harden-runner@e14015d583714f6e62063499dc959a02595150a1 # v2.21.1
        with:
          egress-policy: audit

@@ -36,7 +36,7 @@ jobs:

    steps:
      - name: Harden Runner
-        uses: step-security/harden-runner@05e31511f85b41b11d1cf0ef85d0992719546e2c # v2.21.0
+        uses: step-security/harden-runner@e14015d583714f6e62063499dc959a02595150a1 # v2.21.1
        with:
          egress-policy: audit

@@ -76,6 +76,6 @@ jobs:

      # Upload the results to GitHub's code scanning dashboard.
      - name: "Upload to code-scanning"
-        uses: github/codeql-action/upload-sarif@ff2f1c621b7f889edc0d3c761ac2e6a3f8cdb0dd # v4.37.7
+        uses: github/codeql-action/upload-sarif@cdf488f595d80d6e07e03d4674febd5ab45fa938 # v4.37.9
        with:
          sarif_file: results.sarif
@@ -32,7 +32,7 @@ jobs:
    runs-on: ubuntu-latest
    steps:
      - name: Harden Runner
-        uses: step-security/harden-runner@05e31511f85b41b11d1cf0ef85d0992719546e2c # v2.21.0
+        uses: step-security/harden-runner@e14015d583714f6e62063499dc959a02595150a1 # v2.21.1
        with:
          egress-policy: audit

@@ -61,7 +61,7 @@ jobs:

      # Upload SARIF file generated in previous step
      - name: Upload SARIF file
-        uses: github/codeql-action/upload-sarif@ff2f1c621b7f889edc0d3c761ac2e6a3f8cdb0dd # v4.37.7
+        uses: github/codeql-action/upload-sarif@cdf488f595d80d6e07e03d4674febd5ab45fa938 # v4.37.9
        with:
          sarif_file: semgrep.sarif
        if: always()
@@ -16,7 +16,7 @@ jobs:

    steps:
      - name: Harden Runner
-        uses: step-security/harden-runner@05e31511f85b41b11d1cf0ef85d0992719546e2c # v2.21.0
+        uses: step-security/harden-runner@e14015d583714f6e62063499dc959a02595150a1 # v2.21.1
        with:
          egress-policy: audit

@@ -35,7 +35,7 @@ jobs:
    runs-on: ubuntu-latest
    steps:
      - name: Harden Runner
-        uses: step-security/harden-runner@05e31511f85b41b11d1cf0ef85d0992719546e2c # v2.21.0
+        uses: step-security/harden-runner@e14015d583714f6e62063499dc959a02595150a1 # v2.21.1
        with:
          egress-policy: audit

@@ -60,7 +60,7 @@ jobs:
        target: [ci_test_amalgamation, ci_test_single_header, ci_cppcheck, ci_cpplint, ci_reproducible_tests, ci_non_git_tests, ci_offline_testdata, ci_reuse_compliance, ci_test_valgrind]
    steps:
      - name: Harden Runner
-        uses: step-security/harden-runner@05e31511f85b41b11d1cf0ef85d0992719546e2c # v2.21.0
+        uses: step-security/harden-runner@e14015d583714f6e62063499dc959a02595150a1 # v2.21.1
        with:
          egress-policy: audit

@@ -118,7 +118,7 @@ jobs:
    runs-on: ubuntu-latest
    steps:
      - name: Harden Runner
-        uses: step-security/harden-runner@05e31511f85b41b11d1cf0ef85d0992719546e2c # v2.21.0
+        uses: step-security/harden-runner@e14015d583714f6e62063499dc959a02595150a1 # v2.21.1
        with:
          egress-policy: audit

@@ -369,7 +369,7 @@ jobs:
    runs-on: ubuntu-latest
    steps:
      - name: Harden Runner
-        uses: step-security/harden-runner@05e31511f85b41b11d1cf0ef85d0992719546e2c # v2.21.0
+        uses: step-security/harden-runner@e14015d583714f6e62063499dc959a02595150a1 # v2.21.1
        with:
          egress-policy: audit

@@ -392,7 +392,7 @@ jobs:
        target: [ci_test_examples, ci_test_build_documentation]
    steps:
      - name: Harden Runner
-        uses: step-security/harden-runner@05e31511f85b41b11d1cf0ef85d0992719546e2c # v2.21.0
+        uses: step-security/harden-runner@e14015d583714f6e62063499dc959a02595150a1 # v2.21.1
        with:
          egress-policy: audit

@@ -1,4 +1,4 @@
-.PHONY: pretty clean ChangeLog.md release
+.PHONY: pretty clean ChangeLog.md release update_hedley update_hedley_undef

 ##########################################################################
 # configuration
@@ -41,6 +41,8 @@ all:
 	@echo "fuzz_testing_ubjson - prepare fuzz testing of the UBJSON parser"
 	@echo "pretty - beautify code with Artistic Style"
 	@echo "run_benchmarks - build and run benchmarks"
+	@echo "update_hedley - download Hedley and regenerate hedley.hpp / hedley_undef.hpp"
+	@echo "update_hedley_undef - rebuild hedley_undef.hpp from the JSON_HEDLEY_* #define names in hedley.hpp"


 ##########################################################################
@@ -241,11 +243,24 @@ update_hedley:
 	rm -f include/nlohmann/thirdparty/hedley/hedley.hpp include/nlohmann/thirdparty/hedley/hedley_undef.hpp
 	curl https://raw.githubusercontent.com/nemequ/hedley/master/hedley.h -o include/nlohmann/thirdparty/hedley/hedley.hpp
 	$(SED) -i 's/HEDLEY_/JSON_HEDLEY_/g' include/nlohmann/thirdparty/hedley/hedley.hpp
-	grep "[[:blank:]]*#[[:blank:]]*undef" include/nlohmann/thirdparty/hedley/hedley.hpp | grep -v "__" | sort | uniq | $(SED) 's/ //g' | $(SED) 's/undef/undef /g' > include/nlohmann/thirdparty/hedley/hedley_undef.hpp
 	$(SED) -i '1s/^/#pragma once\n\n/' include/nlohmann/thirdparty/hedley/hedley.hpp
-	$(SED) -i '1s/^/#pragma once\n\n/' include/nlohmann/thirdparty/hedley/hedley_undef.hpp
+	$(MAKE) update_hedley_undef
 	$(MAKE) amalgamate

+# Rebuild hedley_undef.hpp from every JSON_HEDLEY_* name that hedley.hpp
+# #defines. Hedley does not #undef all of its public macros internally (see
+# #5408), so grepping those #undef lines misses names such as
+# JSON_HEDLEY_PRAGMA. cmake/scripts/gen_hedley_undef_check.cmake is the
+# single source of truth for this extraction (tests/CMakeLists.txt uses the
+# same script, in MODE=checks, to generate the matching leak-check test), so
+# the vendored header, the generated #undef list, and the regression test
+# cannot drift apart.
+update_hedley_undef:
+	cmake -DHEDLEY_HPP=include/nlohmann/thirdparty/hedley/hedley.hpp \
+	      -DOUTPUT=include/nlohmann/thirdparty/hedley/hedley_undef.hpp \
+	      -DMODE=undef \
+	      -P cmake/scripts/gen_hedley_undef_check.cmake
+
 ##########################################################################
 # serve_header.py
 ##########################################################################
@@ -0,0 +1,112 @@
+# Shared extractor for the JSON_HEDLEY_* macro names defined in hedley.hpp.
+#
+# Every macro that hedley.hpp #defines must be #undef-ed again once json.hpp
+# has been fully processed (see include/nlohmann/detail/macro_unscope.hpp
+# and https://github.com/nlohmann/json/issues/5408). Deriving the macro list
+# straight from hedley.hpp here -- instead of hand-maintaining it in two
+# places -- means hedley_undef.hpp and the regression test that checks for
+# leaked macros can never drift apart, even after a future `make
+# update_hedley` pulls in new macros from upstream Hedley.
+#
+#   MODE=undef  (default): write hedley_undef.hpp (SPDX header, #pragma once,
+#               one #undef per macro name) -- used by `make update_hedley_undef`
+#   MODE=checks:            write one #ifdef/FAIL_CHECK/#endif per macro name,
+#               meant to be #include-d inside a TEST_CASE -- used by
+#               tests/CMakeLists.txt to (re)generate the include for
+#               tests/src/unit-no-macro-leak.cpp
+#
+# Required variables:
+#   HEDLEY_HPP  path to include/nlohmann/thirdparty/hedley/hedley.hpp
+#   OUTPUT      path of the file to (over)write
+# Optional:
+#   MODE        "undef" (default) or "checks"
+
+if(NOT DEFINED HEDLEY_HPP OR NOT DEFINED OUTPUT)
+    message(FATAL_ERROR "HEDLEY_HPP and OUTPUT must be set")
+endif()
+
+if(NOT EXISTS "${HEDLEY_HPP}")
+    message(FATAL_ERROR "Hedley header not found: ${HEDLEY_HPP}")
+endif()
+
+if(NOT DEFINED MODE)
+    set(MODE undef)
+endif()
+
+if(NOT MODE STREQUAL "undef" AND NOT MODE STREQUAL "checks")
+    message(FATAL_ERROR "MODE must be undef or checks, got: ${MODE}")
+endif()
+
+# Line-anchored, like `grep -oE "^[[:blank:]]*#[[:blank:]]*define[[:blank:]]+JSON_HEDLEY_[A-Za-z0-9_]+"`.
+# Unanchored matching would also pick up JSON_HEDLEY_* mentions inside
+# comments or string literals elsewhere in the file, which must not turn
+# into #undef lines.
+file(STRINGS "${HEDLEY_HPP}" hedley_lines)
+set(macro_names)
+foreach(line IN LISTS hedley_lines)
+    if("${line}" MATCHES "^[ \t]*#[ \t]*define[ \t]+(JSON_HEDLEY_[A-Za-z0-9_]+)")
+        list(APPEND macro_names "${CMAKE_MATCH_1}")
+    endif()
+endforeach()
+
+if(NOT macro_names)
+    message(FATAL_ERROR "No JSON_HEDLEY_* macros found in ${HEDLEY_HPP}")
+endif()
+
+list(REMOVE_DUPLICATES macro_names)
+# Lexicographic, locale-independent (ASCII-only names) -- matches `LC_ALL=C sort`.
+list(SORT macro_names COMPARE STRING)
+list(LENGTH macro_names macro_count)
+
+set(generated "")
+if(MODE STREQUAL "undef")
+    # Same banner `make update_hedley_undef` would stamp by hand, so the
+    # recipe is self-contained and its output is byte-stable across reruns.
+    # The embedded SPDX tags below are part of the *generated* file's
+    # content, not a REUSE header for this .cmake script itself (which is
+    # already covered by the blanket "Files: *" rule in .reuse/dep5) -- keep
+    # them wrapped in REUSE-IgnoreStart/End so `reuse lint` does not try to
+    # parse "MIT\n")" as this file's own SPDX-License-Identifier value.
+    # REUSE-IgnoreStart
+    string(APPEND generated "//     __ _____ _____ _____\n")
+    string(APPEND generated "//  __|  |   __|     |   | |  JSON for Modern C++\n")
+    string(APPEND generated "// |  |  |__   |  |  | | | |  version 3.12.0\n")
+    string(APPEND generated "// |_____|_____|_____|_|___|  https://github.com/nlohmann/json\n")
+    string(APPEND generated "//\n")
+    string(APPEND generated "// SPDX-FileCopyrightText: 2013-2026 Niels Lohmann <https://nlohmann.me>\n")
+    string(APPEND generated "// SPDX-License-Identifier: MIT\n")
+    # REUSE-IgnoreEnd
+    string(APPEND generated "\n")
+    string(APPEND generated "#pragma once\n")
+    string(APPEND generated "\n")
+    foreach(name IN LISTS macro_names)
+        string(APPEND generated "#undef ${name}\n")
+    endforeach()
+else()
+    string(APPEND generated "// This file is generated by cmake/scripts/gen_hedley_undef_check.cmake\n")
+    string(APPEND generated "// from include/nlohmann/thirdparty/hedley/hedley.hpp. Do not edit it by\n")
+    string(APPEND generated "// hand -- it is regenerated on every build. ${macro_count} macros checked.\n\n")
+    foreach(name IN LISTS macro_names)
+        string(APPEND generated "#ifdef ${name}\n")
+        string(APPEND generated "    FAIL_CHECK(\"${name} leaked after including nlohmann/json.hpp\");\n")
+        string(APPEND generated "#endif\n")
+    endforeach()
+endif()
+
+get_filename_component(output_dir "${OUTPUT}" DIRECTORY)
+if(output_dir)
+    file(MAKE_DIRECTORY "${output_dir}")
+endif()
+
+# Avoid rewriting the file (and busting downstream incremental rebuilds)
+# when the content has not actually changed.
+set(write_output TRUE)
+if(EXISTS "${OUTPUT}")
+    file(READ "${OUTPUT}" existing_content)
+    if(existing_content STREQUAL generated)
+        set(write_output FALSE)
+    endif()
+endif()
+if(write_output)
+    file(WRITE "${OUTPUT}" "${generated}")
+endif()
@@ -14,11 +14,7 @@ To store objects in C++, a type is defined by the template parameters explained
 ## Template parameters

 `ArrayType`
-:   container type to store arrays. It must be a vector-like container: the library uses `operator[]`, `at()`, and
-    `resize()`, and requires random-access iterators. `#!cpp std::vector` and `#!cpp std::deque` qualify;
-    `#!cpp std::list` does not. See
-    [Template Parameter Requirements](../../features/types/template_parameters.md#arraytype) for the full list of
-    requirements.
+:   container type to store arrays (e.g., `std::vector` or `std::list`)

 `AllocatorType`
 :   the allocator to use for objects (e.g., `std::allocator`)
@@ -70,4 +66,3 @@ Arrays are stored as pointers in a `basic_json` type. That is, for any access to
 ## Version history

 - Added in version 1.0.0.
- Made `capacity()` optional, so that array types such as `#!cpp std::deque` can be used, in version 3.13.0.
@@ -42,9 +42,7 @@ represent a byte array in modern C++.
    `value_type` must additionally be exactly one byte wide (e.g., `std::uint8_t`/`char`/`std::byte`): the binary
    serializers (CBOR, MessagePack, BSON, UBJSON) read and write the container's raw bytes via
    `reinterpret_cast`, which is only correct for byte-sized elements -- a container like
-    `#!cpp std::vector<std::intptr_t>` will not work as `BinaryType`. The elements must be stored contiguously, and
-    the binary readers additionally require `resize()` and `operator[]`. See
-    [Template Parameter Requirements](../../features/types/template_parameters.md#binarytype) for the full list.
+    `#!cpp std::vector<std::intptr_t>` will not work as `BinaryType`.

 ## Notes

@@ -52,11 +50,6 @@ represent a byte array in modern C++.

 The default values for `BinaryType` is `#!cpp std::vector<std::uint8_t>`.

-#### Supported byte types
-
-`#!cpp std::vector<std::uint8_t>`, `#!cpp std::vector<char>`, and `#!cpp std::vector<std::byte>` are supported.
-Regardless of which of them is configured, [`dump`](dump.md) writes the bytes as the numbers 0..255.
-
 #### Custom BinaryType behavior

 When a custom `BinaryType` is configured (other than the default `#!cpp std::vector<std::uint8_t>`), you can assign
@@ -133,6 +126,3 @@ type `#!cpp binary_t*` must be dereferenced.
 ## Version history

 - Added in version 3.8.0. Changed the type of subtype to `std::uint64_t` in version 3.10.0.
- Fixed [`dump`](dump.md), [`std::hash`](std_hash.md), and [`to_ubjson`](to_ubjson.md) for byte types that are not
-  integers (e.g., `#!cpp std::byte`) in version 3.13.0. `dump` now writes the bytes of a signed byte type (e.g.,
-  `#!cpp char`) as 0..255 rather than as negative numbers.
@@ -11,14 +11,6 @@ literals `#!json true` and `#!json false`.

 To store boolean values in C++, a type is defined by the template parameter  `BooleanType` which chooses the type to use.

-## Template parameters
-
-`BooleanType`
-:   the type to store booleans. As it is stored directly inside a `basic_json` value (in a union), it must be a
-    trivially default-constructible, trivially copyable, and trivially destructible type that is convertible to and
-    from `#!cpp bool`. See
-    [Template Parameter Requirements](../../features/types/template_parameters.md#booleantype).
-
 ## Notes

 #### Default type
@@ -35,10 +35,6 @@ class basic_json;
 | `BinaryType`         | type for binary arrays                                                    | [`binary_t`](binary_t.md)                   |
 | `CustomBaseClass`    | extension point for user code                                             | [`json_base_class_t`](json_base_class_t.md) |

-The library imposes a number of requirements on these types that are not expressed as C++ concepts, such as the
-container operations `object_t` and `array_t` must provide, or the fact that `StringType` must be `char`-based. They
-are collected in [Template Parameter Requirements](../../features/types/template_parameters.md).
-
 ## Specializations

 - [**json**](../json.md) - default specialization
@@ -21,11 +21,8 @@ The default value for `CustomBaseClass` is `void`. In this case, an

 #### Limitations

-The type `CustomBaseClass` has to be a default-constructible, non-`final` class.
+The type `CustomBaseClass` has to be a default-constructible class.
 `basic_json` only supports copy/move construction/assignment if `CustomBaseClass` does so as well.
-A `CustomBaseClass` with non-static data members forfeits `basic_json`'s
-[standard layout](https://en.cppreference.com/w/cpp/named_req/StandardLayoutType) guarantee. See
-[Template Parameter Requirements](../../features/types/template_parameters.md#custombaseclass).

 ## Examples

@@ -19,12 +19,6 @@ using json_serializer = JSONSerializer<T, SFINAE>;

 The default values for `json_serializer` is [`adl_serializer`](../adl_serializer/index.md).

-#### Requirements
-
-A custom serializer must provide `#!cpp static void to_json(basic_json&, T)` for every type it serializes, and either
-`#!cpp static void from_json(const basic_json&, T&)` or `#!cpp static T from_json(const basic_json&)` for every type it
-deserializes. See [Template Parameter Requirements](../../features/types/template_parameters.md#jsonserializer).
-
 ## Examples

 ??? example
@@ -20,16 +20,6 @@ used.
 To store floating-point numbers in C++, a type is defined by the template parameter `NumberFloatType` which chooses the
 type to use.

-## Template parameters
-
-`NumberFloatType`
-:   the type to store floating-point numbers. Parsing and serialization are implemented in terms of
-    `#!cpp std::strtof`/`#!cpp std::strtod`/`#!cpp std::strtold` and `#!cpp std::snprintf`, so the type must be
-    `#!cpp float`, `#!cpp double`, or `#!cpp long double`. The
-    [binary formats](../../features/binary_formats/index.md) additionally require `#!cpp float` or `#!cpp double`,
-    because they have no encoding for `#!cpp long double`. See
-    [Template Parameter Requirements](../../features/types/template_parameters.md#numberfloattype).
-
 ## Notes

 #### Default type
@@ -20,13 +20,6 @@ used.
 To store integer numbers in C++, a type is defined by the template parameter `NumberIntegerType` which chooses the type
 to use.

-## Template parameters
-
-`NumberIntegerType`
-:   the type to store signed integers. It must be a **signed integral** type (`#!cpp std::is_integral`) with a
-    `#!cpp std::numeric_limits` specialization, and it is stored directly inside a `basic_json` value. See
-    [Template Parameter Requirements](../../features/types/template_parameters.md#numberintegertype-and-numberunsignedtype).
-
 ## Notes

 #### Default type
@@ -20,14 +20,6 @@ used.
 To store unsigned integer numbers in C++, a type is defined by the template parameter `NumberUnsignedType` which chooses
 the type to use.

-## Template parameters
-
-`NumberUnsignedType`
-:   the type to store unsigned integers. It must be an **unsigned integral** type (`#!cpp std::is_integral`) with a
-    `#!cpp std::numeric_limits` specialization, and it must be able to represent the absolute value of every
-    [`number_integer_t`](number_integer_t.md) value. See
-    [Template Parameter Requirements](../../features/types/template_parameters.md#numberintegertype-and-numberunsignedtype).
-
 ## Notes

 #### Default type
@@ -30,5 +30,3 @@ and [`default_object_comparator_t`](default_object_comparator_t.md) otherwise.
 - Added in version 3.0.0.
 - Changed to be conditionally defined as `#!cpp typename object_t::key_compare` or `default_object_comparator_t` in
  version 3.11.0.
- Fixed the fallback to `default_object_comparator_t`, which previously failed to compile for object types without a
-  `key_compare` member type, in version 3.13.0.
@@ -18,11 +18,7 @@ To store objects in C++, a type is defined by the template parameters described
 ## Template parameters

 `ObjectType`
-:   the container to store objects. Its template parameters must have the same order and meaning as those of
-    `std::map`; in particular, the third parameter is a comparator. `#!cpp std::unordered_map`, whose third parameter
-    is a hash function, therefore needs an adapter -- see
-    [Template Parameter Requirements](../../features/types/template_parameters.md#objecttype) for the full list of
-    requirements, an adapter example, and the containers that are known to work.
+:   the container to store objects (e.g., `std::map` or `std::unordered_map`)

 `StringType`
 :   the type of the keys or names (e.g., `std::string`). The comparison function `std::less<StringType>` is used to
@@ -126,4 +122,3 @@ the object is silently converted as an array of key-value pairs, which is incorr
 ## Version history

 - Added in version 1.0.0.
- Allowed object types whose `erase(iterator)` returns `#!cpp void` in version 3.13.0.
@@ -34,6 +34,10 @@ Strong guarantee: if an exception is thrown, there are no changes in the JSON va
  ("add", "remove", "move")
 - Throws [`out_of_range.411`](../../home/exceptions.md#jsonexceptionout_of_range411) if an "add" operation's target
  location has a parent that is neither an object nor an array.
+- Throws [`out_of_range.413`](../../home/exceptions.md#jsonexceptionout_of_range413) if a "remove" operation's target
+  location has a parent that is neither an object nor an array.
+- Throws [`out_of_range.414`](../../home/exceptions.md#jsonexceptionout_of_range414) if a "move" operation's "from"
+  location is a proper prefix of its "path" location.
 - Throws [`other_error.501`](../../home/exceptions.md#jsonexceptionother_error501) if "test" operation was
  unsuccessful.

@@ -75,3 +79,7 @@ is thrown. In any case, the original value is not changed: the patch is applied
 - Added in version 2.0.0.
 - Added [`out_of_range.411`](../../home/exceptions.md#jsonexceptionout_of_range411) and stopped relying on an internal assertion when an "add" operation's
  target location has a non-object/non-array parent in version 3.13.0.
+- Added [`out_of_range.413`](../../home/exceptions.md#jsonexceptionout_of_range413) and stopped silently ignoring a "remove" operation whose target
+  location has a non-object/non-array parent in version 3.13.0.
+- Added [`out_of_range.414`](../../home/exceptions.md#jsonexceptionout_of_range414) and rejected a "move" operation whose "from" location is a proper
+  prefix of its "path" location instead of silently producing a corrupted result in version 3.13.0.
@@ -30,6 +30,10 @@ No guarantees, value may be corrupted by an unsuccessful patch operation.
  ("add", "remove", "move")
 - Throws [`out_of_range.411`](../../home/exceptions.md#jsonexceptionout_of_range411) if an "add" operation's target
  location has a parent that is neither an object nor an array.
+- Throws [`out_of_range.413`](../../home/exceptions.md#jsonexceptionout_of_range413) if a "remove" operation's target
+  location has a parent that is neither an object nor an array.
+- Throws [`out_of_range.414`](../../home/exceptions.md#jsonexceptionout_of_range414) if a "move" operation's "from"
+  location is a proper prefix of its "path" location.
 - Throws [`other_error.501`](../../home/exceptions.md#jsonexceptionother_error501) if "test" operation was
  unsuccessful.

@@ -72,3 +76,7 @@ function throws an exception.
 - Added in version 3.11.0.
 - Added [`out_of_range.411`](../../home/exceptions.md#jsonexceptionout_of_range411) and stopped relying on an internal assertion when an "add" operation's
  target location has a non-object/non-array parent in version 3.13.0.
+- Added [`out_of_range.413`](../../home/exceptions.md#jsonexceptionout_of_range413) and stopped silently ignoring a "remove" operation whose target
+  location has a non-object/non-array parent in version 3.13.0.
+- Added [`out_of_range.414`](../../home/exceptions.md#jsonexceptionout_of_range414) and rejected a "move" operation whose "from" location is a proper
+  prefix of its "path" location instead of silently producing a corrupted result in version 3.13.0.
@@ -23,11 +23,6 @@ JSON class into byte-sized characters during deserialization.
    `StringType`. To work with wide-character data, convert it to/from UTF-8 at the boundary instead -- see the
    FAQ's [wide string handling](../../home/faq.md#wide-string-handling) section for a conversion recipe.

-    Beyond the character type, the library expects a substantial part of the `#!cpp std::string` interface (contiguous
-    null-terminated `data()`, `substr()`, `find()`, `append()`, ...). See
-    [Template Parameter Requirements](../../features/types/template_parameters.md#stringtype) for the full list and
-    for the string types that are known to work.
-
 ## Notes

 #### Default type
@@ -83,5 +78,3 @@ and an example.
 ## Version history

 - Added in version 1.0.0.
- Removed the requirement that `string_t` be implicitly convertible from `#!cpp std::string`, which the BSON writer and
-  the UBJSON reader relied on, in version 3.13.0.
@@ -37,14 +37,7 @@ Linear in the size of the JSON value.
 ## Notes

 Empty objects and arrays are flattened by [`flatten()`](flatten.md) to `#!json null` values and cannot unflattened to
-their original type.
-
-A flattened array and a flattened object whose keys are array indices are indistinguishable, because both are
-described by the same JSON pointers. A value is therefore restored as an array if and only if one of its keys is the
-reference token `0`, and as an object otherwise: `#!json {"2": 1}` is restored unchanged, whereas `#!json {"0": 1}` is
-restored as `#!json [1]`. This decision does not depend on the order in which the flattened object is iterated.
-
-Apart from these two cases, for a JSON value `j`, the following is always true:
+their original type. Apart from this example, for a JSON value `j`, the following is always true:
 `#!cpp j == j.flatten().unflatten()`.

 ## Examples
@@ -70,4 +63,3 @@ Apart from these two cases, for a JSON value `j`, the following is always true:
 ## Version history

 - Added in version 2.0.0.
- Made the array/object decision independent of the object's iteration order in version 3.13.0.
@@ -12,11 +12,9 @@
 Controls how exceptions are handled by the library.

 1. This macro overrides [`#!cpp catch`](https://en.cppreference.com/w/cpp/language/try_catch) calls inside the library.
-   The argument is the type of the exception to catch. The library uses it in a single place: to swallow any exception
-   escaping the parent-pointer check that [`JSON_DIAGNOSTICS`](json_diagnostics.md) adds to the class invariant. The
-   places where the library catches its own [`json::out_of_range`](../../home/exceptions.md#out-of-range) exceptions
-   use `JSON_INTERNAL_CATCH` instead, which `JSON_CATCH_USER` also overrides unless `JSON_INTERNAL_CATCH_USER` is
-   defined. The macro is always followed by a scope.
+   The argument is the type of the exception to catch. As of version 3.8.0, the library only catches `std::out_of_range`
+   exceptions internally to rethrow them as [`json::out_of_range`](../../home/exceptions.md#out-of-range) exceptions.
+   The macro is always followed by a scope.
 2. This macro overrides `#!cpp throw` calls inside the library. The argument is the exception to be thrown. Note that
   `JSON_THROW_USER` should leave the current scope (e.g., by throwing or aborting), as continuing after it may yield
   undefined behavior.
@@ -1,19 +0,0 @@
-#include <iostream>
-#include <map>
-
-#include <nlohmann/json.hpp>
-
-#include "custom_array_type.hpp"
-
-using custom_json = nlohmann::basic_json<std::map, custom_array_type>;
-
-int main()
-{
-    custom_json j = custom_json::array();
-    j.push_back(1);
-    j.push_back(2);
-    j.push_back(3);
-
-    std::cout << j.dump() << std::endl;
-    std::cout << std::boolalpha << (custom_json::parse(j.dump()) == j) << std::endl;
-}
@@ -1,152 +0,0 @@
-#pragma once
-
-#include <memory>
-#include <utility>
-#include <vector>
-
-// A minimal, self-contained ArrayType built around a private std::vector.
-// See https://json.nlohmann.me/features/types/template_parameters/#arraytype
-template<class T, class Allocator = std::allocator<T>>
-class custom_array_type
-{
-    using vector_t = std::vector<T, Allocator>;
-    vector_t data_;
-
-  public:
-    using value_type = typename vector_t::value_type;
-    using size_type = typename vector_t::size_type;
-    using iterator = typename vector_t::iterator;
-    using const_iterator = typename vector_t::const_iterator;
-
-    custom_array_type() = default;
-    custom_array_type(const custom_array_type&) = default;
-    custom_array_type(custom_array_type&&) = default;
-    custom_array_type& operator=(const custom_array_type&) = default;
-    custom_array_type& operator=(custom_array_type&&) = default;
-
-    template<class InputIt>
-    custom_array_type(InputIt first, InputIt last) : data_(first, last) {}
-
-    custom_array_type(size_type count, const T& value) : data_(count, value) {}
-
-    iterator begin()
-    {
-        return data_.begin();
-    }
-    iterator end()
-    {
-        return data_.end();
-    }
-    const_iterator begin() const
-    {
-        return data_.begin();
-    }
-    const_iterator end() const
-    {
-        return data_.end();
-    }
-    const_iterator cbegin() const
-    {
-        return data_.cbegin();
-    }
-    const_iterator cend() const
-    {
-        return data_.cend();
-    }
-
-    bool empty() const
-    {
-        return data_.empty();
-    }
-    size_type size() const
-    {
-        return data_.size();
-    }
-    size_type max_size() const
-    {
-        return data_.max_size();
-    }
-    void clear()
-    {
-        data_.clear();
-    }
-    void resize(size_type n)
-    {
-        data_.resize(n);
-    }
-
-    T& operator[](size_type pos)
-    {
-        return data_[pos];
-    }
-    const T& operator[](size_type pos) const
-    {
-        return data_[pos];
-    }
-
-    T& back()
-    {
-        return data_.back();
-    }
-    const T& back() const
-    {
-        return data_.back();
-    }
-
-    void push_back(const T& value)
-    {
-        data_.push_back(value);
-    }
-    void push_back(T&& value)
-    {
-        data_.push_back(std::move(value));
-    }
-
-    template<class... Args>
-    void emplace_back(Args&& ... args)
-    {
-        data_.emplace_back(std::forward<Args>(args)...);
-    }
-
-    void pop_back()
-    {
-        data_.pop_back();
-    }
-
-    iterator insert(const_iterator pos, const T& value)
-    {
-        return data_.insert(pos, value);
-    }
-    iterator insert(const_iterator pos, size_type count, const T& value)
-    {
-        return data_.insert(pos, count, value);
-    }
-    template<class InputIt>
-    iterator insert(const_iterator pos, InputIt first, InputIt last)
-    {
-        return data_.insert(pos, first, last);
-    }
-
-    iterator erase(const_iterator pos)
-    {
-        return data_.erase(pos);
-    }
-    iterator erase(const_iterator first, const_iterator last)
-    {
-        return data_.erase(first, last);
-    }
-
-    void swap(custom_array_type& other)
-    {
-        data_.swap(other.data_);
-    }
-
-    friend bool operator==(const custom_array_type& lhs, const custom_array_type& rhs)
-    {
-        return lhs.data_ == rhs.data_;
-    }
-    friend bool operator<(const custom_array_type& lhs, const custom_array_type& rhs)
-    {
-        return lhs.data_ < rhs.data_;
-    }
-};
@@ -1,2 +0,0 @@
-[1,2,3]
-true
@@ -1,21 +0,0 @@
-#include <cstdint>
-#include <iostream>
-#include <map>
-#include <string>
-#include <vector>
-
-#include <nlohmann/json.hpp>
-
-#include "custom_binary_type.hpp"
-
-using custom_json = nlohmann::basic_json<std::map, std::vector, std::string, bool,
-      std::int64_t, std::uint64_t, double, std::allocator,
-      nlohmann::adl_serializer, custom_binary_type>;
-
-int main()
-{
-    const auto j = custom_json::binary({0x01, 0x02, 0x03});
-
-    std::cout << j.dump() << std::endl;
-    std::cout << std::boolalpha << (custom_json::from_cbor(custom_json::to_cbor(j)) == j) << std::endl;
-}
@@ -1,112 +0,0 @@
-#pragma once
-
-#include <cstdint>
-#include <initializer_list>
-#include <vector>
-
-// A minimal, self-contained BinaryType built around a private std::vector.
-// See https://json.nlohmann.me/features/types/template_parameters/#binarytype
-class custom_binary_type
-{
-    using vector_t = std::vector<std::uint8_t>;
-    vector_t data_;
-
-  public:
-    using value_type = vector_t::value_type;
-    using size_type = vector_t::size_type;
-    using iterator = vector_t::iterator;
-    using const_iterator = vector_t::const_iterator;
-
-    custom_binary_type() = default;
-    custom_binary_type(const custom_binary_type&) = default;
-    custom_binary_type(custom_binary_type&&) = default;
-    custom_binary_type& operator=(const custom_binary_type&) = default;
-    custom_binary_type& operator=(custom_binary_type&&) = default;
-
-    template<class InputIt>
-    custom_binary_type(InputIt first, InputIt last) : data_(first, last) {}
-
-    // so basic_json::binary({0x01, 0x02}) can build one directly
-    custom_binary_type(std::initializer_list<std::uint8_t> init) : data_(init) {}
-
-    size_type size() const
-    {
-        return data_.size();
-    }
-    bool empty() const
-    {
-        return data_.empty();
-    }
-    void clear()
-    {
-        data_.clear();
-    }
-    void resize(size_type n)
-    {
-        data_.resize(n);
-    }
-
-    // read-only is enough: the writers only ever read from a binary value
-    const std::uint8_t* data() const
-    {
-        return data_.data();
-    }
-
-    std::uint8_t& operator[](size_type pos)
-    {
-        return data_[pos];
-    }
-    std::uint8_t operator[](size_type pos) const
-    {
-        return data_[pos];
-    }
-
-    std::uint8_t& back()
-    {
-        return data_.back();
-    }
-    std::uint8_t back() const
-    {
-        return data_.back();
-    }
-
-    iterator begin()
-    {
-        return data_.begin();
-    }
-    iterator end()
-    {
-        return data_.end();
-    }
-    const_iterator begin() const
-    {
-        return data_.begin();
-    }
-    const_iterator end() const
-    {
-        return data_.end();
-    }
-    const_iterator cbegin() const
-    {
-        return data_.cbegin();
-    }
-    const_iterator cend() const
-    {
-        return data_.cend();
-    }
-
-    template<class InputIt>
-    iterator insert(const_iterator pos, InputIt first, InputIt last)
-    {
-        return data_.insert(pos, first, last);
-    }
-
-    friend bool operator==(const custom_binary_type& lhs, const custom_binary_type& rhs)
-    {
-        return lhs.data_ == rhs.data_;
-    }
-    friend bool operator<(const custom_binary_type& lhs, const custom_binary_type& rhs)
-    {
-        return lhs.data_ < rhs.data_;
-    }
-};
@@ -1,2 +0,0 @@
-{"bytes":[1,2,3],"subtype":null}
-true
@@ -1,26 +0,0 @@
-#include <iostream>
-#include <type_traits>
-#include <vector>
-
-#include <nlohmann/json.hpp>
-
-#include "custom_object_type.hpp"
-
-using custom_json = nlohmann::basic_json<custom_object_type, std::vector>;
-
-int main()
-{
-    custom_json j;
-    j["pi"] = 3.141;
-    j["happy"] = true;
-    j["list"] = {1, 2, 3};
-
-    std::cout << j.dump(2) << std::endl;
-    std::cout << std::boolalpha << (custom_json::parse(j.dump()) == j) << std::endl;
-
-    // custom_object_type has no key_compare member, so object_comparator_t
-    // falls back to its default
-    std::cout << std::boolalpha
-              << std::is_same<custom_json::object_comparator_t, custom_json::default_object_comparator_t>::value
-              << std::endl;
-}
@@ -1,144 +0,0 @@
-#pragma once
-
-#include <map>
-#include <utility>
-
-// A minimal, self-contained ObjectType built around a private std::map.
-// key_compare is deliberately not exposed: when an ObjectType has no
-// key_compare member, the library falls back to its own default comparator.
-// See https://json.nlohmann.me/features/types/template_parameters/#objecttype
-template<class Key, class T, class Compare, class Allocator>
-class custom_object_type
-{
-    using map_t = std::map<Key, T, Compare, Allocator>;
-    map_t data_;
-
-  public:
-    using key_type = typename map_t::key_type;
-    using mapped_type = typename map_t::mapped_type;
-    using value_type = typename map_t::value_type;
-    using size_type = typename map_t::size_type;
-    using iterator = typename map_t::iterator;
-    using const_iterator = typename map_t::const_iterator;
-
-    custom_object_type() = default;
-    custom_object_type(const custom_object_type&) = default;
-    custom_object_type(custom_object_type&&) = default;
-    custom_object_type& operator=(const custom_object_type&) = default;
-    custom_object_type& operator=(custom_object_type&&) = default;
-
-    template<class InputIt>
-    custom_object_type(InputIt first, InputIt last) : data_(first, last) {}
-
-    iterator begin()
-    {
-        return data_.begin();
-    }
-    iterator end()
-    {
-        return data_.end();
-    }
-    const_iterator begin() const
-    {
-        return data_.begin();
-    }
-    const_iterator end() const
-    {
-        return data_.end();
-    }
-    const_iterator cbegin() const
-    {
-        return data_.cbegin();
-    }
-    const_iterator cend() const
-    {
-        return data_.cend();
-    }
-
-    bool empty() const
-    {
-        return data_.empty();
-    }
-    size_type size() const
-    {
-        return data_.size();
-    }
-    size_type max_size() const
-    {
-        return data_.max_size();
-    }
-    void clear()
-    {
-        data_.clear();
-    }
-
-    iterator find(const key_type& key)
-    {
-        return data_.find(key);
-    }
-    const_iterator find(const key_type& key) const
-    {
-        return data_.find(key);
-    }
-    size_type count(const key_type& key) const
-    {
-        return data_.count(key);
-    }
-
-    std::pair<iterator, bool> emplace(const key_type& key, const mapped_type& value)
-    {
-        return data_.emplace(key, value);
-    }
-
-    std::pair<iterator, bool> insert(const value_type& value)
-    {
-        return data_.insert(value);
-    }
-
-    template<class InputIt>
-    void insert(InputIt first, InputIt last)
-    {
-        data_.insert(first, last);
-    }
-
-    mapped_type& operator[](const key_type& key)
-    {
-        return data_[key];
-    }
-
-    mapped_type& at(const key_type& key)
-    {
-        return data_.at(key);
-    }
-    const mapped_type& at(const key_type& key) const
-    {
-        return data_.at(key);
-    }
-
-    iterator erase(iterator pos)
-    {
-        return data_.erase(pos);
-    }
-    iterator erase(iterator first, iterator last)
-    {
-        return data_.erase(first, last);
-    }
-    size_type erase(const key_type& key)
-    {
-        return data_.erase(key);
-    }
-
-    void swap(custom_object_type& other)
-    {
-        data_.swap(other.data_);
-    }
-
-    friend bool operator==(const custom_object_type& lhs, const custom_object_type& rhs)
-    {
-        return lhs.data_ == rhs.data_;
-    }
-    friend bool operator<(const custom_object_type& lhs, const custom_object_type& rhs)
-    {
-        return lhs.data_ < rhs.data_;
-    }
-};
@@ -1,11 +0,0 @@
-{
-  "happy": true,
-  "list": [
-    1,
-    2,
-    3
-  ],
-  "pi": 3.141
-}
-true
-true
@@ -1,20 +0,0 @@
-#include <iostream>
-#include <map>
-#include <vector>
-
-#include <nlohmann/json.hpp>
-
-#include "custom_string_type.hpp"
-
-using custom_json = nlohmann::basic_json<std::map, std::vector, custom_string_type>;
-
-int main()
-{
-    custom_json j;
-    j["pi"] = 3.141;
-    j["happy"] = true;
-    j["list"] = {1, 2, 3};
-
-    std::cout << j.dump(2) << std::endl;
-    std::cout << std::boolalpha << (custom_json::parse(j.dump()) == j) << std::endl;
-}
@@ -1,134 +0,0 @@
-#pragma once
-
-#include <ostream>
-#include <string>
-
-// A minimal, self-contained StringType built around a private std::string.
-// Wraps rather than inherits, so it exposes exactly what the library needs
-// and nothing more of std::string's interface.
-//
-// Covers the "Always required" members, the extras needed for the binary
-// formats, and the extras needed for JSON Pointer / flatten / unflatten /
-// diff. Extending it further (e.g. for std::hash<basic_json> or to_bson) is
-// a matter of adding the extra members listed in the "Required for other
-// functionality" table.
-//
-// See https://json.nlohmann.me/features/types/template_parameters/#stringtype
-class custom_string_type
-{
-    std::string data_;
-
-  public:
-    using value_type = char;
-    using size_type = std::string::size_type;
-    using iterator = std::string::iterator;
-    using const_iterator = std::string::const_iterator;
-
-    static constexpr size_type npos = std::string::npos;
-
-    custom_string_type() = default;
-    custom_string_type(const custom_string_type&) = default;
-    custom_string_type(custom_string_type&&) = default;
-    custom_string_type& operator=(const custom_string_type&) = default;
-    custom_string_type& operator=(custom_string_type&&) = default;
-
-    // not explicit: the library relies on being able to hand it a string literal
-    custom_string_type(const char* s) : data_(s) {}
-    custom_string_type(const char* s, size_type count) : data_(s, count) {}
-    custom_string_type(size_type count, char ch) : data_(count, ch) {}
-
-    size_type size() const
-    {
-        return data_.size();
-    }
-    bool empty() const
-    {
-        return data_.empty();
-    }
-    void clear()
-    {
-        data_.clear();
-    }
-    void resize(size_type n)
-    {
-        data_.resize(n);
-    }
-    void resize(size_type n, char c)
-    {
-        data_.resize(n, c);
-    }
-    void reserve(size_type n)
-    {
-        data_.reserve(n);
-    }
-
-    // must stay null-terminated -- the parser hands this to std::strtoull &
-    // friends; std::string::data() has guaranteed that since C++11
-    const char* data() const
-    {
-        return data_.data();
-    }
-
-    void push_back(char c)
-    {
-        data_.push_back(c);
-    }
-
-    char& operator[](size_type pos)
-    {
-        return data_[pos];
-    }
-    char operator[](size_type pos) const
-    {
-        return data_[pos];
-    }
-
-    custom_string_type& append(const char* s, size_type count)
-    {
-        data_.append(s, count);
-        return *this;
-    }
-    custom_string_type& append(const custom_string_type& other)
-    {
-        data_.append(other.data_);
-        return *this;
-    }
-
-    size_type find_first_of(char c, size_type pos = 0) const
-    {
-        return data_.find_first_of(c, pos);
-    }
-
-    iterator begin()
-    {
-        return data_.begin();
-    }
-    iterator end()
-    {
-        return data_.end();
-    }
-    const_iterator begin() const
-    {
-        return data_.begin();
-    }
-    const_iterator end() const
-    {
-        return data_.end();
-    }
-
-    friend bool operator==(const custom_string_type& lhs, const custom_string_type& rhs)
-    {
-        return lhs.data_ == rhs.data_;
-    }
-    friend bool operator<(const custom_string_type& lhs, const custom_string_type& rhs)
-    {
-        return lhs.data_ < rhs.data_;
-    }
-
-    // not required by the library itself, but dump() returns a custom_string_type
-    // and this makes `std::cout << j.dump()` work as expected
-    friend std::ostream& operator<<(std::ostream& os, const custom_string_type& s)
-    {
-        return os << s.data_;
-    }
-};
@@ -1,10 +0,0 @@
-{
-  "happy": true,
-  "list": [
-    1,
-    2,
-    3
-  ],
-  "pi": 3.141
-}
-true
@@ -4,8 +4,8 @@
 Hello, world!
 1 2 3 4 5 

-string: "Hello, world!"
 number: {"floating-point":17.23,"integer":42}
 null: null
+string: "Hello, world!"
 boolean: true
 array: [1,2,3,4,5]
@@ -4,8 +4,8 @@
 Hello, world!
 1 2 3 4 5 

-string: "Hello, world!"
 number: {"floating-point":17.23,"integer":42}
 null: null
+string: "Hello, world!"
 boolean: true
 array: [1,2,3,4,5]
@@ -4,9 +4,9 @@
 Hello, world!
 1 2 3 4 5 

-string: "Hello, world!"
 number: {"floating-point":17.23,"integer":42}
 null: null
+string: "Hello, world!"
 boolean: true
 array: [1,2,3,4,5]
 [json.exception.type_error.302] type must be boolean, but is string
@@ -125,6 +125,7 @@ The library uses the following mapping from JSON values types to BJData types ac

    - `"_ArrayType_"` is one of `uint8`, `int8`, `uint16`, `int16`, `uint32`, `int32`, `uint64`, `int64`, `single`,
      `double`, `char`, or `byte`,
+    - `"_ArraySize_"` is an array, since the dimensions are written as the ND-array header's length,
    - every entry of `"_ArraySize_"` is a non-negative integer, and their product is representable as a `std::size_t`,
    - `"_ArrayData_"` holds exactly that many elements, and
    - every element of `"_ArrayData_"` is a number of the kind named by `"_ArrayType_"` (a floating-point number for
@@ -51,11 +51,7 @@ If you do want to preserve the **insertion order**, you can use the type [`nlohm
    --8<-- "examples/ordered_json.output"
    ```

-Alternatively, [`nlohmann::fifo_map`](https://github.com/nlohmann/fifo_map) also preserves the insertion order and, unlike [`ordered_map`](../api/ordered_map.md), keeps a lookup index, so it does not have the quadratic cost described below. It is used through a small adapter ([integration](https://github.com/nlohmann/json/issues/485#issuecomment-333652309)).
-
-If the order does not matter and you only want faster lookup, `boost::unordered_flat_map`, `absl::flat_hash_map`, `absl::node_hash_map`, and several other hash maps work through an adapter that restores the template argument order `basic_json` expects; see [Template Parameter Requirements](types/template_parameters.md#objecttype). Note these are *unordered*, not insertion-ordered.
-
-[`tsl::ordered_map`](https://github.com/Tessil/ordered-map) cannot be used: its iterators expose the mapped value as `const`, while `basic_json` needs to modify it in place.
+Alternatively, you can use a more sophisticated ordered map like [`tsl::ordered_map`](https://github.com/Tessil/ordered-map) ([integration](https://github.com/nlohmann/json/issues/546#issuecomment-304447518)) or [`nlohmann::fifo_map`](https://github.com/nlohmann/fifo_map) ([integration](https://github.com/nlohmann/json/issues/485#issuecomment-333652309)).

 The [`ordered_map`](../api/ordered_map.md) behind `nlohmann::ordered_json` is deliberately minimal and has no lookup
 index, so every key access is a linear scan and building an object of `n` keys costs O(n²). This is unnoticeable at
@@ -79,8 +79,7 @@ template<
    class NumberFloatType = double,
    template<typename U> class AllocatorType = std::allocator,
    template<typename T, typename SFINAE = void> class JSONSerializer = adl_serializer,
-    class BinaryType = std::vector<std::uint8_t>,
-    class CustomBaseClass = void
+    class BinaryType = std::vector<std::uint8_t>
 >
 class basic_json;
 ```
@@ -107,10 +106,6 @@ using number_float_t = NumberFloatType;
 using binary_t = nlohmann::byte_container_with_subtype<BinaryType>;
 ```

-Not every type can be passed for these template arguments: the library uses the resulting types in ways that imply a
-number of requirements, for instance that `StringType` is `char`-based or that `ArrayType` is vector-like. These
-requirements are collected in [Template Parameter Requirements](template_parameters.md).
-

 ## Objects

@@ -1,747 +0,0 @@
-# Template Parameter Requirements
-
-Class [`basic_json`](../../api/basic_json/index.md) is configurable through eleven template parameters. The library
-never formally states what a type passed for one of these parameters has to provide -- the requirements are implied by
-the way the library uses the resulting [`object_t`](../../api/basic_json/object_t.md),
-[`array_t`](../../api/basic_json/array_t.md), [`string_t`](../../api/basic_json/string_t.md), etc. This page collects
-these requirements so they do not have to be discovered by trial and error. Each section lists the concrete types
-that are known to work for that parameter and the ones that do not, checked against Boost 1.83, Abseil 20250127.0,
-Folly, EASTL 3.21, `ankerl::unordered_dense`, `phmap`, `gtl`, `robin_hood`, `tsl::ordered_map`, and Qt 6.
-
-## How to read this page
-
-Requirements are split into two groups:
-
- **Always required** -- needed to instantiate `basic_json` at all, or needed by functions that virtually every program
-  uses (construction, element access, [`dump`](../../api/basic_json/dump.md)).
- **Required for ...** -- only needed when a particular part of the API is instantiated. Member function templates are
-  only instantiated when they are used, so a type may be perfectly usable even though it does not satisfy these
-  requirements, as long as the corresponding functions are never called.
-
-!!! warning "Requirements are not checked"
-
-    Three requirements are checked with a `#!cpp static_assert`: the array iterator category, the width of
-    [`BinaryType`](#binarytype)'s `value_type`, and [`NumberUnsignedType`](#numberintegertype-and-numberunsignedtype)
-    being at least as wide as [`NumberIntegerType`](#numberintegertype-and-numberunsignedtype). The rest are not
-    diagnosed with dedicated error messages, and violating most of them results in a compiler error somewhere inside
-    the library. Four violations are not caught at compile time at all:
-
-    - A [`StringType`](#stringtype) whose `data()` is not null-terminated compiles and silently misparses numbers,
-      because the lexer hands the buffer to `#!cpp std::strtoull`/`#!cpp std::strtoll`/`#!cpp std::strtod`.
-    - A stateful [`AllocatorType`](#allocatortype) compiles and silently ignores its state: allocation, deallocation,
-      and [`get_allocator()`](../../api/basic_json/get_allocator.md) each use a different default-constructed instance.
-    - The two [cross-specialization conversions](#cross-specialization-conversions) below. These abort on an assertion
-      in a normal build, and only fail silently under `#!cpp NDEBUG`.
-
-## Overview
-
-| Template parameter                                                | Default                           | Notable substitutes                                                   |
-|-------------------------------------------------------------------|-----------------------------------|-----------------------------------------------------------------------|
-| [`ObjectType`](#objecttype)                                       | `std::map`                        | [`nlohmann::ordered_map`](../../api/ordered_map.md), Abseil hash maps |
-| [`ArrayType`](#arraytype)                                         | `std::vector`                     | `#!cpp std::deque`                                                    |
-| [`StringType`](#stringtype)                                       | `std::string`                     | `std::string`-like types over `char`                                  |
-| [`BooleanType`](#booleantype)                                     | `bool`                            | none worth using                                                      |
-| [`NumberIntegerType`](#numberintegertype-and-numberunsignedtype)  | `std::int64_t`                    | any signed integer type                                               |
-| [`NumberUnsignedType`](#numberintegertype-and-numberunsignedtype) | `std::uint64_t`                   | any unsigned integer type at least as wide as `NumberIntegerType`     |
-| [`NumberFloatType`](#numberfloattype)                             | `double`                          | `float` (`long double`: no binary formats)                            |
-| [`AllocatorType`](#allocatortype)                                 | `std::allocator`                  | stateless allocators                                                  |
-| [`JSONSerializer`](#jsonserializer)                               | `adl_serializer`                  | serializers with the same interface                                   |
-| [`BinaryType`](#binarytype)                                       | `#!cpp std::vector<std::uint8_t>` | `#!cpp std::vector<char>`                                             |
-| [`CustomBaseClass`](#custombaseclass)                             | `void`                            | any default-constructible class                                       |
-
-!!! warning "Third-party containers and incomplete types"
-
-    `object_t` is instantiated inside the definition of `basic_json` -- it is probed for a `key_compare` member to
-    form [`object_comparator_t`](../../api/basic_json/object_comparator_t.md) -- i.e. while `basic_json` is still an
-    incomplete type. `#!cpp std::map` is required by the standard to support incomplete mapped types; most
-    third-party maps are not, and inspecting the mapped type at class scope (for instance with
-    `#!cpp std::is_trivially_move_assignable`) makes them unusable as `ObjectType`, no matter how their template
-    arguments are adapted. This rules out `absl::btree_map`, `phmap::btree_map`, `gtl::btree_map`,
-    `robin_hood::unordered_node_map`, `folly::F14FastMap`, and `eastl::hash_map`.
-
-    `array_t` is only *named* in the class definition and is not instantiated until `basic_json` is complete, so an
-    `ArrayType` that inspects its value type at class scope is generally fine -- `boost::container::small_vector` and
-    `static_vector` both reject incomplete value types yet work here. `absl::InlinedVector` is the exception: the
-    `#!cpp std::is_trivially_move_assignable<basic_json>` it evaluates while instantiating itself re-enters the
-    library's own trait machinery mid-instantiation.
-
-!!! note "Folly requires C++20"
-
-    Folly's headers use `#!cpp consteval` and `#!cpp std::type_identity`, so any `basic_json` specialization that
-    names a Folly type has to be compiled as C++20 or later, whatever the rest of the library supports.
-
-## `ObjectType`
-
-`ObjectType` is instantiated as
-
-```cpp
-using object_t = ObjectType<StringType,                                    // key_type
-                            basic_json,                                    // mapped_type
-                            default_object_comparator_t,                   // key_compare
-                            AllocatorType<std::pair<const StringType,
-                                                    basic_json>>>;         // allocator_type
-```
-
-i.e., the template arguments follow the order and meaning of `std::map`.
-
-### Always required
-
- The template must be usable with **four** type arguments in the order shown above. The third argument is a
-  **comparator**; containers that expect something else in this position (e.g., a hash function) need an alias template
-  or wrapper -- see [Notes](#notes).
- An optional member type `key_compare`. If it is present it becomes
-  [`object_comparator_t`](../../api/basic_json/object_comparator_t.md); otherwise
-  [`default_object_comparator_t`](../../api/basic_json/default_object_comparator_t.md) is used.
- Member types `key_type`, `mapped_type`, `value_type`, and `iterator`.
- `value_type` must behave like `#!cpp std::pair<const key_type, mapped_type>`; the library accesses `.first` and
-  `.second` on it.
- `iterator` must be default-constructible and satisfy
-  [LegacyBidirectionalIterator](https://en.cppreference.com/w/cpp/named_req/BidirectionalIterator). The type returned
-  by `cbegin()`/`cend()` must satisfy the same requirements.
- Constructors: default, copy, move, and from an iterator range `(first, last)`.
- Member functions `begin()`, `end()`, `cbegin()`, `cend()`, `empty()`, `size()`, `max_size()`, `clear()`,
-  `find(key)`, `count(key)`, `emplace(key, value)`, `insert(value_type)`, `insert(first, last)`, `operator[](key)`,
-  `erase(iterator)`, and `erase(first, last)`. `erase(iterator)` may return the following iterator or `#!cpp void`;
-  in the latter case the library computes the successor itself, before erasing.
- `erase(key)` is **optional**: if the container does not provide one, the library falls back to `find(key)` followed
-  by `erase(iterator)`.
- `at(key)` is required only by [`to_ubjson`](../../api/basic_json/to_ubjson.md) and
-  [`to_bjdata`](../../api/basic_json/to_bjdata.md), but every container tried here provides it.
- `emplace` and `insert(value_type)` must return `#!cpp std::pair<iterator, bool>` and must have **unique-key**
-  semantics; multimaps cannot be used.
- The type must be swappable (via `std::swap` or an ADL `swap`).
- The comparison operators `==` and `<`; `!=`, `<=`, `>`, and `>=` are derived from them. Where the library uses
-  three-way comparison (C++20), `==` and `<=>` are required **instead** -- the six two-way operators do not satisfy
-  it. They implement [`basic_json`'s comparison operators](../../api/basic_json/operator_eq.md).
-
-### Required for heterogeneous key lookup
-
-The overloads of [`at`](../../api/basic_json/at.md), [`operator[]`](../../api/basic_json/operator%5B%5D.md),
-[`find`](../../api/basic_json/find.md), [`contains`](../../api/basic_json/contains.md),
-[`count`](../../api/basic_json/count.md), [`erase`](../../api/basic_json/erase.md), and
-[`value`](../../api/basic_json/value.md) that accept a key type other than `object_t::key_type` require
-
- a **transparent** comparator, i.e. [`object_comparator_t`](../../api/basic_json/object_comparator_t.md) has a member
-  type `is_transparent` (this is why the default comparator is `#!cpp std::less<>` since C++14), and
- corresponding heterogeneous `find`, `count`, `erase`, and `operator[]` overloads on the container.
-
-### Notes
-
-#### `std::unordered_map` needs an adapter
-
-`#!cpp std::unordered_map` cannot be passed directly: its third template parameter is a hash function, but
-`basic_json` passes a comparator in that position. An alias template or wrapper that restores the expected argument
-order makes it usable:
-
-```cpp
-template<class Key, class T, class IgnoredCompare, class Allocator>
-struct unordered_map_object
-    : std::unordered_map<Key, T, std::hash<Key>, std::equal_to<Key>, Allocator>
-{
-    using base_t = std::unordered_map<Key, T, std::hash<Key>, std::equal_to<Key>, Allocator>;
-    using base_t::base_t;
-};
-
-using unordered_json = nlohmann::basic_json<unordered_map_object>;
-```
-
-Whether `#!cpp std::unordered_map` can be instantiated at all depends on the standard library: `object_t` is formed
-while `basic_json` is still incomplete (see the warning above), and libstdc++ 9 needs the size of the mapped type to
-instantiate the hash map's node type, so the adapter does not compile there. Newer libstdc++ versions, and the hash
-maps listed below, do not have that problem.
-
-The adapter above works verbatim for Abseil's, Boost's, `phmap`'s and `gtl`'s hash maps, which all place the hash
-function third and take a `#!cpp std::pair<const Key, T>` allocator fifth. Two need a different adapter:
-
- `ankerl::unordered_dense` expects an allocator over `#!cpp std::pair<Key, T>` (non-const key), so the allocator has
-  to be rebound to that or dropped.
- `robin_hood`'s fifth parameter is the non-type `MaxLoadFactor100`, so its adapter must drop the allocator entirely.
-
-None of these hash maps defines `key_compare`, so all of them additionally rely on `object_comparator_t` falling back
-to [`default_object_comparator_t`](../../api/basic_json/default_object_comparator_t.md); see
-[`object_comparator_t`](../../api/basic_json/object_comparator_t.md).
-
-#### Abseil hash maps
-
-`absl::flat_hash_map` and `absl::node_hash_map` tolerate an incomplete value type, but they take a hash function as
-their third template argument. The same adapter as for `#!cpp std::unordered_map` makes them usable:
-
-```cpp
-template<class Key, class T, class IgnoredCompare, class Allocator>
-struct flat_hash_object
-    : absl::flat_hash_map<Key, T, absl::Hash<Key>, std::equal_to<Key>, Allocator>
-{
-    using base_t = absl::flat_hash_map<Key, T, absl::Hash<Key>, std::equal_to<Key>, Allocator>;
-    using base_t::base_t;
-};
-
-using flat_hash_json = nlohmann::basic_json<flat_hash_object>;
-```
-
-`absl::node_hash_map` keeps references to the mapped values valid across insertions; `absl::flat_hash_map` does not,
-which makes it behave like [`ordered_json`](../../api/ordered_json.md) with respect to
-[iterator invalidation](../../api/basic_json/index.md#iterator-invalidation). Both expose a `capacity()` member
-function, so [`JSON_DIAGNOSTICS`](../../api/macros/json_diagnostics.md) treats them conservatively and keeps the
-parent pointers correct either way.
-
-#### Iteration order
-
-The library never relies on the container's iteration order for correctness; it does determine the order in which
-object keys are serialized by [`dump`](../../api/basic_json/dump.md) and visited by
-[`items`](../../api/basic_json/items.md). See [Object Order](../object_order.md).
-
-#### `capacity()` marks a container as insertion-ordered
-
-With [`JSON_DIAGNOSTICS`](../../api/macros/json_diagnostics.md) enabled, the library detects insertion-ordered maps by
-probing for a `capacity()` member function (`nlohmann::ordered_map` inherits it from `std::vector`) and refreshes all
-parent pointers after every insertion. An `ObjectType` that happens to have a `capacity()` member is therefore treated
-conservatively -- this is correct, but slower.
-
-#### Key order and duplicate keys
-
-The library does not sort or de-duplicate keys itself; the behavior described in
-[`object_t`](../../api/basic_json/object_t.md) is entirely the behavior of the chosen container.
-
-!!! tip "Reference implementation"
-
-    `docs/mkdocs/docs/examples/custom_object_type.hpp` wraps a private `#!cpp std::map` and satisfies every
-    requirement above. It does not define `key_compare`, so `object_comparator_t` falls back to
-    [`default_object_comparator_t`](../../api/basic_json/default_object_comparator_t.md) -- a good starting point for
-    a custom `ObjectType`.
-
-    ```cpp
-    --8<-- "examples/custom_object_type.hpp"
-    ```
-
-??? example "Compiling and using it"
-
-    ```cpp
-    --8<-- "examples/custom_object_type.cpp"
-    ```
-
-    Output:
-
-    ```json
-    --8<-- "examples/custom_object_type.output"
-    ```
-
-### Compatible containers
-
-| Container                                                                        | Notes                                                                         |
-|----------------------------------------------------------------------------------|-------------------------------------------------------------------------------|
-| `#!cpp std::map` (default)                                                       |                                                                               |
-| [`nlohmann::ordered_map`](../../api/ordered_map.md)                              | used by [`ordered_json`](../../api/ordered_json.md); keeps insertion order    |
-| [`nlohmann::fifo_map`](https://github.com/nlohmann/fifo_map)                     | keeps insertion order; adapter puts `fifo_map_compare` in the comparator slot |
-| `boost::container::map`, `boost::container::flat_map`                            | no adapter needed                                                             |
-| `#!cpp std::unordered_map`                                                       | through the adapter above; not with libstdc++ 9, see the note                 |
-| `boost::unordered_map`, `boost::unordered_flat_map`, `boost::unordered_node_map` | through the adapter above                                                     |
-| `absl::flat_hash_map`, `absl::node_hash_map`                                     | through the adapter above; `flat_hash_map` moves mapped values on rehash      |
-| `phmap::flat_hash_map`, `phmap::node_hash_map`, `gtl::flat_hash_map`             | through the adapter above                                                     |
-| `ankerl::unordered_dense::map` and `segmented_map`                               | adapter must rebind or drop the allocator                                     |
-| `robin_hood::unordered_flat_map`                                                 | adapter must drop the allocator                                               |
-| `folly::F14NodeMap`                                                              | through the adapter above; requires C++20, see the note above                 |
-| `folly::sorted_vector_map`                                                       | alias must drop the allocator, whose value type it disagrees on               |
-
-### Containers that cannot be used
-
-| Container                                                                | Reason                                                                                                              |
-|--------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------|
-| `absl::btree_map`, `phmap::btree_map`, `gtl::btree_map`                  | require a complete mapped type                                                                                      |
-| `robin_hood::unordered_node_map`, `folly::F14FastMap`, `eastl::hash_map` | require a complete mapped type                                                                                      |
-| `eastl::map`                                                             | EASTL iterators do not work with `#!cpp std::iterator_traits`                                                       |
-| `tsl::ordered_map`                                                       | its iterators expose the mapped value as `#!cpp const`                                                              |
-| `QMap`                                                                   | no `value_type` member type                                                                                         |
-| `QHash`                                                                  | its `value_type` is the mapped type rather than a key/value pair, and its iterators dereference to the mapped value |
-| `#!cpp std::multimap`, `#!cpp std::unordered_multimap`                   | `emplace` does not return `#!cpp std::pair<iterator, bool>`                                                         |
-
-## `ArrayType`
-
-`ArrayType` is instantiated as
-
-```cpp
-using array_t = ArrayType<basic_json, AllocatorType<basic_json>>;
-```
-
-### Always required
-
- The template must be usable with **two** type arguments (value type and allocator).
- Member types `value_type` and `iterator`.
- Constructors: default, copy, and move; and from an iterator range `(first, last)`.
- Member functions `begin()`, `end()`, `cbegin()`, `cend()`, `empty()`, `size()`, `max_size()`, `clear()`,
-  `operator[](size_type)`, `back()`, `push_back()`, `emplace_back()`, `pop_back()`, `resize()`,
-  `insert()` (single element, count, and range), `erase(pos)`, and `erase(first, last)`.
-  `basic_json::insert(pos, initializer_list)` goes through the range overload, so no initializer-list `insert` is
-  needed. `at(size_type)` is **not** required: [`basic_json::at(size_type)`](../../api/basic_json/at.md) checks the
-  index itself and then uses `operator[]`.
- `iterator` must be default-constructible, and it as well as the type returned by `cbegin()`/`cend()` must satisfy
-  [LegacyRandomAccessIterator](https://en.cppreference.com/w/cpp/named_req/RandomAccessIterator).
-  A `#!cpp static_assert` only checks for
-  [LegacyBidirectionalIterator](https://en.cppreference.com/w/cpp/named_req/BidirectionalIterator), but
-  [`dump`](../../api/basic_json/dump.md) (`cend() - 1`),
-  [`erase(idx)`](../../api/basic_json/erase.md) (`begin() + idx`), and the random-access operations of
-  [`basic_json::iterator`](../../api/basic_json/begin.md) require random access.
- The comparison operators, as for [`ObjectType`](#objecttype): `==` and `<`, or `==` and `<=>` under C++20.
-
-### Required for individual functions
-
- A member type `value_type`, for [`to_bson`](../../api/basic_json/to_bson.md) of an array.
- A constructor from `(count, value)`, for
-  [`basic_json(size_type, const basic_json&)`](../../api/basic_json/basic_json.md).
- Swappability, via `#!cpp std::swap` or an ADL `swap`, for [`swap(array_t&)`](../../api/basic_json/swap.md).
-
-!!! note "`capacity()` is optional"
-
-    With [`JSON_DIAGNOSTICS`](../../api/macros/json_diagnostics.md) enabled, the library reads `array_t::capacity()`
-    to find out whether adding an element reallocated the array and moved its elements, which would invalidate the
-    parent pointers. An array type without a `capacity()` member function is handled conservatively: the parent
-    pointers of all elements are refreshed after every insertion, which makes adding *n* elements cost O(*n*²). Only
-    diagnostics builds pay this; without them `capacity()` is never called.
-
-!!! tip "Reference implementation"
-
-    `docs/mkdocs/docs/examples/custom_array_type.hpp` wraps a private `#!cpp std::vector` and satisfies every
-    requirement above -- a good starting point for a custom `ArrayType`.
-
-    ```cpp
-    --8<-- "examples/custom_array_type.hpp"
-    ```
-
-??? example "Compiling and using it"
-
-    ```cpp
-    --8<-- "examples/custom_array_type.cpp"
-    ```
-
-    Output:
-
-    ```json
-    --8<-- "examples/custom_array_type.output"
-    ```
-
-### Compatible containers
-
-| Container                                               | Notes                                                                                     |
-|---------------------------------------------------------|-------------------------------------------------------------------------------------------|
-| `#!cpp std::vector` (default)                           |                                                                                           |
-| `#!cpp std::deque`                                      | references survive appends, but not insertions elsewhere; see the `capacity()` note above |
-| `#!cpp std::pmr::vector`                                | through an alias, as the allocator comes from `AllocatorType` instead                     |
-| `boost::container::vector`, `deque`, `devector`         |                                                                                           |
-| `boost::container::stable_vector`                       | the only one tried that keeps references valid across *every* insertion                   |
-| `boost::container::small_vector`, `folly::small_vector` | through an alias that fixes the inline capacity                                           |
-| `boost::container::static_vector`                       | through the same kind of alias, for arrays that stay within the fixed capacity            |
-| `folly::fbvector`                                       | requires C++20, see the note above                                                        |
-
-### Containers that cannot be used
-
-| Container                           | Reason                                                                                        |
-|-------------------------------------|-----------------------------------------------------------------------------------------------|
-| `#!cpp std::list`                   | no `operator[]`, and no random-access iterators                                               |
-| `eastl::vector`, `QList`, `QVector` | no `max_size()`; they handle the incomplete value type fine                                   |
-| `absl::InlinedVector`               | requires a complete value type, see the note above                                            |
-| `absl::FixedArray`                  | the size is fixed at construction, so `resize`, `push_back`, `insert` and `erase` are missing |
-
-## `StringType`
-
-`StringType` is used **both** for JSON string values and for the keys of JSON objects
-(`string_t` and `object_t::key_type`).
-
-### Always required
-
- A member type `value_type` that is one byte wide and `char`-compatible. The library stores and processes UTF-8
-  encoded `char` data and hands `data()` to `#!cpp std::strtoull`/`#!cpp std::strtoll`.
-  `#!cpp std::wstring`, `#!cpp std::u16string`, and `#!cpp std::u32string` are **not** valid choices; see the FAQ on
-  [wide string handling](../../home/faq.md#wide-string-handling).
- Constructors: default, copy, move, from `#!cpp const char*` (which must not be `#!cpp explicit`), from
-  `#!cpp (const char*, size_type)`, and from `#!cpp (size_type, char)`; and copy or move assignment.
- Member functions `size()`, `clear()`, `resize(n, c)`, `data()`, `push_back(char)`, and `operator[]`
-  (const and non-const, returning references). `c_str()` and `back()` are **not** required.
- `data()` must return a pointer to a contiguous, **null-terminated** buffer -- the parser hands it to
-  `#!cpp std::strtoull`. A type whose `data()` is not null-terminated does not fail to compile; it silently
-  misparses numbers.
- `append(const char*, size_type)`, used by [`dump`](../../api/basic_json/dump.md), and `append(const StringType&)`,
-  used by the CBOR reader for indefinite-length strings. The library's internal string concatenation additionally has
-  to append a `#!cpp char` and a `#!cpp const char*`; for each it selects between `append(arg)`, `#!cpp operator+=`,
-  `append(first, last)`, and `append(data, size)`.
- The comparison operator `==` against another `StringType`, and `<` for use as a key of the chosen
-  [`ObjectType`](#objecttype) (with the default comparator, `#!cpp std::less<>` must be able to compare two
-  `StringType` values, and a `StringType` with the key types used for lookup). `!=` is never applied to a
-  `StringType`, and `==` against `#!cpp const char*` is resolved by the implicit `#!cpp const char*` constructor.
-
-### Required for the binary formats
-
- `resize(n)`, used by the readers to make room for a block of bytes.
- Non-const `operator[]`, into which the readers `#!cpp std::memcpy` those bytes. A non-`#!cpp const` `data()` would
-  serve just as well, but `#!cpp std::string` has only had one since C++17, and the library still supports C++11.
-
-### Required for JSON Pointer, `flatten`, and `diff`
-
- A static member `npos` and the member function `find_first_of(char, size_type)` -- together with `data()`,
-  `reserve(n)`, and `append(const char*, size_type)` they implement the escaping and unescaping of reference tokens
-  described in RFC 6901. Neither `find(const StringType&, size_type)`, nor `substr(pos, count)`, nor
-  `replace(pos, count, const StringType&)` is required.
- `empty()`.
- `begin()` and `end()` -- used by
-  [`operator[](const json_pointer&)`](../../api/basic_json/operator%5B%5D.md) to decide whether a reference token
-  denotes an array index.
-
-### Required for other functionality
-
-| Functionality                                                                                                                     | Additional requirement                                                                                                                                                                       |
-|-----------------------------------------------------------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
-| [`diff`](../../api/basic_json/diff.md), [`items`](../../api/basic_json/items.md), [`std::hash`](../../api/basic_json/std_hash.md) | conversion of a `#!cpp std::size_t` to `StringType`: either assignability from the result of `#!cpp std::to_string`, or an ADL overload `#!cpp void int_to_string(StringType&, std::size_t)` |
-| [`std::hash<basic_json>`](../../api/basic_json/std_hash.md)                                                                       | additionally a specialization of `#!cpp std::hash<StringType>`                                                                                                                               |
-| [`to_bson`](../../api/basic_json/to_bson.md)                                                                                      | `find(value_type)` and `npos`                                                                                                                                                                |
-| [`parse`](../../api/basic_json/parse.md) from a `string_t`                                                                        | the input adapters must accept it; otherwise pass a character range                                                                                                                          |
-| `#!cpp operator<<(std::ostream&, const json_pointer&)`                                                                            | streamability to `#!cpp std::ostream`                                                                                                                                                        |
-| exception messages                                                                                                                | `data()` and `size()`, or `begin()` and `end()`                                                                                                                                              |
-
-### Compatible types
-
-| Type                                                            | Notes                                                                                                                                                                                                                                         |
-|-----------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
-| `#!cpp std::string` (default)                                   |                                                                                                                                                                                                                                               |
-| `#!cpp std::basic_string` with a custom **stateless** allocator |                                                                                                                                                                                                                                               |
-| `#!cpp std::pmr::string`                                        | see the warning below before relying on the memory resource                                                                                                                                                                                   |
-| `boost::container::string`                                      | needs a user-supplied `#!cpp std::hash` specialization (Boost provides `boost::hash` instead)                                                                                                                                                 |
-| `folly::fbstring`                                               | requires C++20, see the note above                                                                                                                                                                                                            |
-| `eastl::string`                                                 | needs a user-supplied `#!cpp std::hash` and an ADL `int_to_string` (it is not assignable from a `#!cpp std::string`); [`parse`](../../api/basic_json/parse.md) does not accept it directly -- pass a character range or a `#!cpp std::string` |
-| a custom string class in a user-defined namespace               | if the requirements above are met                                                                                                                                                                                                             |
-
-### Types that cannot be used
-
-| Type                                                                 | Reason                                                                                                  |
-|----------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------|
-| `#!cpp std::wstring`, `#!cpp std::u16string`, `#!cpp std::u32string` | the character type is not one byte wide                                                                 |
-| `#!cpp std::u8string`                                                | one byte wide, but `#!cpp char8_t` is not `#!cpp char`-compatible                                       |
-| `absl::Cord`                                                         | no `value_type`, and the storage is not contiguous                                                      |
-| `QString`                                                            | no `append(const char*, size_type)`; its `QChar` is also two bytes wide, though that is never diagnosed |
-
-!!! warning "A `std::pmr::string` mostly does not use the memory resource you choose"
-
-    `basic_json` cannot be given an allocator or a memory resource. `AllocatorType` is default-constructed at every
-    allocation and has to be stateless (see [`AllocatorType`](#allocatortype)), and string values the library creates
-    are constructed with their own default allocator. So:
-
-    - Every string the library itself produces -- from [`parse`](../../api/basic_json/parse.md), from
-      [`dump`](../../api/basic_json/dump.md), or by default construction -- allocates from
-      `#!cpp std::pmr::get_default_resource()`.
-    - **Copying** an arena-backed string into a value silently drops its memory resource: the copy lands on the
-      default resource, because `#!cpp std::pmr::polymorphic_allocator` does not propagate on copy construction.
-      Nothing warns about this.
-    - **Moving** one in does keep it, and later growth still allocates from that arena -- but it does not survive a
-      copy of the enclosing `basic_json`.
-    - Passing `#!cpp std::pmr::polymorphic_allocator` as `AllocatorType` does not work around any of this; it does
-      not compile.
-
-    Apart from moving a string in, the only way to redirect these allocations is the process-global
-    `#!cpp std::pmr::set_default_resource()`.
-
-!!! tip "Reference implementation"
-
-    `docs/mkdocs/docs/examples/custom_string_type.hpp` wraps a private `#!cpp std::string` and satisfies every
-    requirement above -- a good starting point for a custom `StringType`. The unit test
-    `tests/src/unit-alt-string.cpp` contains a more thorough variant, `alt_string`, exercised against a larger part
-    of the API.
-
-    ```cpp
-    --8<-- "examples/custom_string_type.hpp"
-    ```
-
-??? example "Compiling and using it"
-
-    ```cpp
-    --8<-- "examples/custom_string_type.cpp"
-    ```
-
-    Output:
-
-    ```json
-    --8<-- "examples/custom_string_type.output"
-    ```
-
-## `BooleanType`
-
-`boolean_t` is stored **directly** inside `basic_json`, as a member of an anonymous union.
-
-### Always required
-
- A literal type that is trivially default-constructible, trivially copyable, and trivially destructible; otherwise the
-  union's special member functions are deleted.
- **Implicitly** convertible from `#!cpp bool` -- an `#!cpp explicit` constructor is not enough, because the
-  `to_json` overload for a custom `BooleanType` is constrained on `#!cpp std::is_convertible` -- and contextually
-  convertible to `#!cpp bool` (here an `#!cpp explicit operator bool` is fine).
- Comparison operators `==`, `!=`, `<`, `<=`, `>`, `>=` (or `<=>`).
- Convertible from and to `#!cpp bool` through the serializer, because
-  [`get<bool>()`](../../api/basic_json/get.md) is used internally.
-
-There is little reason to use anything other than `#!cpp bool` here.
-
-### Compatible types
-
-`#!cpp bool` is the only usable choice. Another trivially copyable type that is implicitly convertible to and from
-`#!cpp bool` -- `#!cpp std::uint8_t`, say -- does compile, and JSON booleans still round-trip, but the type then
-serves as both `boolean_t` and an ordinary integer: `basic_json` can no longer be constructed or assigned from a
-`#!cpp std::uint8_t` at all (the boolean and unsigned-integer `to_json` overloads become ambiguous), and
-[`get<std::uint8_t>()`](../../api/basic_json/get.md) on a number throws
-[`type_error.302`](../../home/exceptions.md#jsonexceptiontype_error302) instead of returning the value.
-
-## `NumberIntegerType` and `NumberUnsignedType`
-
-Both types are stored **directly** inside `basic_json`'s union.
-
-### Always required
-
- `#!cpp std::is_integral` must be satisfied: `NumberIntegerType` must be a **signed** integer type,
-  `NumberUnsignedType` an **unsigned** integer type. Class types are not supported -- among others, the constructors
-  taking integer values are constrained on `#!cpp std::is_integral`.
- Trivially default-constructible, trivially copyable, and trivially destructible (union member).
- `#!cpp std::numeric_limits` must be specialized for both types.
- `NumberUnsignedType` must be able to represent the absolute value of every `NumberIntegerType` value; serialization
-  of negative numbers converts the value to `NumberUnsignedType`. A `#!cpp static_assert` requires it to be at least as
-  wide as `NumberIntegerType`, which is what that amounts to for the standard integer types.
- Both types must fit into the internal 64-character number buffer used by
-  [`dump`](../../api/basic_json/dump.md), which is the case for all standard integer types.
- [`std::hash<basic_json>`](../../api/basic_json/std_hash.md) additionally requires `#!cpp std::hash` specializations.
-
-### Notes
-
-The number types influence what the parser accepts: an integer literal that does not round-trip through the chosen type
-is stored as [`number_float_t`](../../api/basic_json/number_float_t.md) instead. Choosing types narrower than 64 bits
-therefore silently changes parse results rather than raising an error. See
-[Number Handling](number_handling.md) for details.
-
-### Compatible types
-
-| Type pair                                                                                    | Support                                                                                                                                                                                          |
-|----------------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
-| `#!cpp std::int64_t` / `#!cpp std::uint64_t` (default)                                       | full                                                                                                                                                                                             |
-| `#!cpp std::int32_t` / `#!cpp std::uint32_t`, `#!cpp long long` / `#!cpp unsigned long long` | full; narrower types change which literals the parser can represent                                                                                                                              |
-| any other pair of standard signed/unsigned integer types                                     | full                                                                                                                                                                                             |
-| class types, enumerations                                                                    | not usable; `#!cpp std::is_integral` must hold                                                                                                                                                   |
-| `#!cpp bool`, or a type already used for another member of the union                         | not usable; `#!cpp std::is_integral<bool>` is in fact `#!cpp true`, but the `get_impl_ptr` overloads for `boolean_t`, `number_integer_t`, `number_unsigned_t` and `number_float_t` would collide |
-
-## `NumberFloatType`
-
-`number_float_t` is stored **directly** inside `basic_json`'s union.
-
-### Always required
-
- Trivially default-constructible, trivially copyable, and trivially destructible (union member).
- `#!cpp std::numeric_limits` must be specialized; `max_digits10` is used to size the conversion.
- `#!cpp std::isfinite` must be applicable to the type.
-
-### Required for parsing and serialization
-
-`NumberFloatType` must be one of `#!cpp float`, `#!cpp double`, or `#!cpp long double`:
-
- The [parser](../parsing/index.md) converts number literals with `#!cpp std::strtof`, `#!cpp std::strtod`, or
-  `#!cpp std::strtold`; the library provides overloads for exactly these three types.
- [`dump`](../../api/basic_json/dump.md) falls back to `#!cpp std::snprintf` with the `%g` and `%Lg` conversion
-  specifiers, for which the library likewise provides only `#!cpp double` and `#!cpp long double` overloads
-  (`#!cpp float` is promoted to `#!cpp double`).
-
-If `#!cpp std::numeric_limits<NumberFloatType>` describes an IEEE 754 binary32 or binary64 number, `dump` uses the
-Grisu2 algorithm, which produces the shortest representation that round-trips. Otherwise the `snprintf` fallback with
-`max_digits10` digits is used.
-
-### Required for the binary formats
-
-`NumberFloatType` must be `#!cpp float` or `#!cpp double`. The writers for
-[CBOR, MessagePack, UBJSON, BJData, and BSON](../binary_formats/index.md) map a floating-point value onto an IEEE 754
-binary32 or binary64 field and have no encoding for `#!cpp long double`.
-
-### Compatible types
-
-| Type                     | Support                                                                                                               |
-|--------------------------|-----------------------------------------------------------------------------------------------------------------------|
-| `#!cpp double` (default) | full; short round-trip output through Grisu2                                                                          |
-| `#!cpp float`            | full; short round-trip output through Grisu2                                                                          |
-| `#!cpp long double`      | `dump` and `parse` only; the binary format writers do not compile, as they only handle IEEE 754 binary32 and binary64 |
-| any other type           | not usable                                                                                                            |
-
-## `AllocatorType`
-
-`AllocatorType` is instantiated with **one** argument, for each of `object_t`, `array_t`, `string_t`, `binary_t`,
-`basic_json`, and `#!cpp std::pair<const StringType, basic_json>`.
-
-### Always required
-
- The template must be usable with exactly one type argument. The library instantiates `AllocatorType<T>` directly and
-  never uses `#!cpp std::allocator_traits<...>::rebind_alloc`.
- It must satisfy the [Allocator](https://en.cppreference.com/w/cpp/named_req/Allocator) named requirement so that
-  `#!cpp std::allocator_traits` can be used with it.
- It must be **default-constructible and stateless**. Objects are allocated with a default-constructed allocator and
-  deallocated with a *different* default-constructed allocator, and
-  [`get_allocator()`](../../api/basic_json/get_allocator.md) returns a default-constructed instance. Allocators
-  carrying state are not supported, so there is no way to tell a `basic_json` where to allocate from; see the note
-  under [`StringType`](#stringtype) for what that means in practice. A stateful allocator is **not diagnosed**: it
-  compiles and silently ignores the state.
- It must support **incomplete types**: `AllocatorType<basic_json>` is instantiated inside the definition of
-  `basic_json` itself.
- `#!cpp std::allocator_traits<AllocatorType<basic_json>>::pointer` becomes
-  [`basic_json::pointer`](../../api/basic_json/index.md#container-types), and iterators are constructed from raw
-  `#!cpp basic_json*` values. The `pointer` type must therefore be a plain pointer; fancy pointers are not supported.
-
-### Compatible types
-
-| Type                                                              | Support                                |
-|-------------------------------------------------------------------|----------------------------------------|
-| `#!cpp std::allocator` (default)                                  | full                                   |
-| a custom stateless allocator template                             | full                                   |
-| stateful allocators, e.g. `#!cpp std::pmr::polymorphic_allocator` | not usable; see the requirements above |
-
-## `JSONSerializer`
-
-`JSONSerializer` is instantiated as `JSONSerializer<T, void>` and defaults to
-[`adl_serializer`](../../api/adl_serializer/index.md).
-
-### Always required
-
- The template must accept **two** type arguments. It does not have to give the second one a default -- `basic_json`
-  declares the parameter as `#!cpp template<typename T, typename SFINAE = void> class JSONSerializer`, so uses such as
-  `#!cpp JSONSerializer<T>` inside the library supply `#!cpp void` themselves. The second parameter exists so that
-  partial specializations can be constrained by SFINAE.
- For every type `T` that is converted **to** a JSON value, a static member function
-  `#!cpp static void to_json(basic_json&, T)` must exist.
- For every type `T` that is converted **from** a JSON value, either
-  `#!cpp static void from_json(const basic_json&, T&)` or `#!cpp static T from_json(const basic_json&)` must exist.
-  The latter form is required for types that are not default-constructible; see
-  [Arbitrary Types Conversions](../arbitrary_types.md).
- To support the [converting constructor](../../api/basic_json/basic_json.md) between different `basic_json`
-  specializations, `to_json` must be available for `boolean_t`, `number_integer_t`, `number_unsigned_t`,
-  `number_float_t`, `string_t`, `object_t`, `array_t`, and `binary_t` of the *source* specialization.
-
-### Compatible types
-
-| Type                                                                      | Support                                                           |
-|---------------------------------------------------------------------------|-------------------------------------------------------------------|
-| [`nlohmann::adl_serializer`](../../api/adl_serializer/index.md) (default) | full                                                              |
-| a class template deriving from `adl_serializer`                           | full; the usual way to change behavior while keeping the defaults |
-| an unrelated template with the same interface                             | full, but it has to handle every type the library converts        |
-
-## `BinaryType`
-
-`BinaryType` is not a JSON type; it is used for the byte strings of the
-[binary formats](../binary_formats/index.md). It is wrapped as
-
-```cpp
-using binary_t = nlohmann::byte_container_with_subtype<BinaryType>;
-```
-
-### Always required
-
- A non-`final` class type -- [`byte_container_with_subtype`](../../api/byte_container_with_subtype/index.md) derives
-  from it publicly.
- A member type `value_type` that is **exactly one byte** wide (e.g., `#!cpp std::uint8_t`, `#!cpp char`, or
-  `#!cpp std::byte`). Readers and writers reinterpret the container's storage as raw bytes, so a wider `value_type` is
-  rejected with a `#!cpp static_assert`.
- Contiguous storage: the binary readers `#!cpp std::memcpy` into `#!cpp &binary[n]`, the writers `reinterpret_cast`
-  `data()`. `#!cpp data() + n` would do for the readers too, but they share one helper with
-  [`StringType`](#stringtype), whose non-`#!cpp const` `data()` is C++17 and later only.
- Default-constructible, copy-constructible, and move-constructible.
- Member functions `size()`, `empty()`, `data()`, `resize()`, `operator[]`, `back()`, `begin()`, `end()`, `cbegin()`,
-  and `cend()` with random-access iterators, and `insert(pos, first, last)`, which the CBOR reader uses to join the
-  chunks of an indefinite-length byte string. `push_back()` is **not** required.
- Comparison operators: `==` is used by
-  [`byte_container_with_subtype`](../../api/byte_container_with_subtype/index.md), the relational operators by
-  [`basic_json`'s comparison operators](../../api/basic_json/operator_le.md).
-
-### Required for individual functions
-
- `clear()`, for [`basic_json::clear()`](../../api/basic_json/clear.md).
-
-`max_size()`, `at()`, `reserve()`, `erase()`, `pop_back()`, and `emplace_back()` are **not** used at all.
-
-See [`binary_t`](../../api/basic_json/binary_t.md) for how a non-default `BinaryType` changes the meaning of assigning
-such a container to a `basic_json` value.
-
-!!! tip "Reference implementation"
-
-    `docs/mkdocs/docs/examples/custom_binary_type.hpp` wraps a private `#!cpp std::vector<std::uint8_t>` and satisfies
-    every requirement above -- a good starting point for a custom `BinaryType`.
-
-    ```cpp
-    --8<-- "examples/custom_binary_type.hpp"
-    ```
-
-??? example "Compiling and using it"
-
-    ```cpp
-    --8<-- "examples/custom_binary_type.cpp"
-    ```
-
-    Output:
-
-    ```json
-    --8<-- "examples/custom_binary_type.output"
-    ```
-
-### Compatible containers
-
-| Container                                                                                   | Notes                                                                     |
-|---------------------------------------------------------------------------------------------|---------------------------------------------------------------------------|
-| `#!cpp std::vector<std::uint8_t>` (default)                                                 |                                                                           |
-| `#!cpp std::vector<char>`, `#!cpp std::vector<std::byte>`                                   | `dump()` writes the bytes as 0..255 whichever is used                     |
-| `boost::container::vector<std::uint8_t>`, `boost::container::small_vector<std::uint8_t, N>` |                                                                           |
-| `absl::InlinedVector<std::uint8_t, N>`                                                      | usable here, unlike as an `ArrayType`, because the value type is complete |
-| `eastl::vector<std::uint8_t>`                                                               | usable here, unlike as an `ArrayType`, because `max_size()` is not needed |
-| `folly::fbvector<std::uint8_t>`                                                             | requires C++20, see the note above                                        |
-
-### Containers that cannot be used
-
-| Container                                            | Reason                                                                                                                                                                                             |
-|------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
-| `QByteArray`                                         | no `empty()` (it spells that `isEmpty()`); its `insert` takes an index rather than an iterator; and it converts to `string_t`, which makes `to_json` ambiguous between a string and a binary value |
-| `#!cpp std::string`                                  | `binary_t::container_type` and `string_t` would be the same type, so the two [`swap`](../../api/basic_json/swap.md) overloads collide and `basic_json` cannot be instantiated at all               |
-| `#!cpp std::deque<std::uint8_t>`                     | storage is not contiguous, so there is no `data()`                                                                                                                                                 |
-| containers whose `value_type` is wider than one byte | see above -- accepted by the compiler, wrong at runtime                                                                                                                                            |
-
-## `CustomBaseClass`
-
-`CustomBaseClass` is an extension point: unless it is `#!cpp void` (the default, which selects the empty
-`nlohmann::json_default_base`), `basic_json` publicly derives from it.
-
-### Always required
-
- A non-`final`, default-constructible class type.
- `basic_json` is copy-/move-constructible and copy-/move-assignable only if `CustomBaseClass` is.
-
-### Notes
-
-`basic_json` is documented to be a
-[StandardLayoutType](https://en.cppreference.com/w/cpp/named_req/StandardLayoutType). Because `basic_json` has
-non-static data members of its own, a `CustomBaseClass` with non-static data members forfeits this guarantee.
-
-Note the namespace of `CustomBaseClass` becomes an associated namespace of `basic_json` for the purpose of
-argument-dependent lookup.
-
-See [`json_base_class_t`](../../api/basic_json/json_base_class_t.md) for an example.
-
-### Compatible types
-
-| Type                                         | Support                                                                    |
-|----------------------------------------------|----------------------------------------------------------------------------|
-| `#!cpp void` (default)                       | an empty base class is used; no effect on `basic_json`                     |
-| any default-constructible, non-`final` class | full; see [`json_base_class_t`](../../api/basic_json/json_base_class_t.md) |
-
-## Cross-specialization conversions
-
-Converting a value from one `basic_json` specialization into another (see the
-[converting constructor](../../api/basic_json/basic_json.md)) imposes two additional requirements that are not
-diagnosed at compile time. With assertions enabled they abort on the `#!cpp JSON_ASSERT` at the end of the converting
-constructor; under `#!cpp NDEBUG` they fail **silently** at runtime:
-
- The target `string_t` must be directly constructible from the source `string_t`. Otherwise the string is converted to
-  an array of character codes.
- The target `object_t::key_type` must be directly constructible from the source object's key type. Otherwise the
-  object is converted to an array of key/value pairs.
-
-See [issue #3425](https://github.com/nlohmann/json/issues/3425), [`string_t`](../../api/basic_json/string_t.md), and
-[`object_t`](../../api/basic_json/object_t.md).
-
-## See also
-
- [Types](index.md) -- overview of how JSON values are stored
- [Number Handling](number_handling.md) -- how the number types affect parsing and serialization
- [Object Order](../object_order.md) -- using an insertion-ordered `ObjectType`
- [`basic_json`](../../api/basic_json/index.md) -- API documentation of the class template
@@ -8,41 +8,72 @@ the result of an internet search. If you know further customers of the library,
 ## Space Exploration

 - [**Peregrine Lunar Lander Flight 01**](https://en.wikipedia.org/wiki/Peregrine_Mission_One) - The library was used for payload management in the **Peregrine Moon Lander**, developed by **Astrobotic Technology** and launched as part of NASA's **Commercial Lunar Payload Services (CLPS)** program. After six days in orbit, the spacecraft was intentionally redirected into Earth's atmosphere, where it burned up over the Pacific Ocean on **January 18, 2024**.
+- [**NASA Unsteady Pressure-Sensitive Paint Processing**](https://github.com/nasa/upsp-processing), NASA software for processing high-speed video recordings of wind tunnel tests on launch vehicle and aircraft models
+- [**Terma TEMU**](https://temu.terma.com/docs/public/temu-release-notes/latest/copying/json-for-modern-cpp.html), an emulator of spacecraft on-board computers used to develop and validate flight software for European space missions

 ## Automotive

 - [**Alexa Auto SDK**](https://github.com/alexa/alexa-auto-sdk), a software development kit enabling the integration of Alexa into automotive systems
 - [**Apollo**](https://github.com/ApolloAuto/apollo), a framework for building autonomous driving systems
 - [**Automotive Grade Linux (AGL)**](https://download.automotivelinux.org/AGL/release/jellyfish/latest/qemux86-64/deploy/licenses/nlohmann-json/), a collaborative open-source platform for automotive software development
+- [**Autoware**](https://github.com/autowarefoundation/autoware_universe), an open-source software stack for autonomous driving built on ROS 2
+- [**Eclipse S-CORE**](https://github.com/eclipse-score/nlohmann_json), an open-source software platform for the software-defined vehicle backed by major automotive manufacturers and suppliers
 - [**Genesis Motor** (infotainment)](http://webmanual.genesis.com/ccIC/AVNT/JW/KOR/English/reference010.html), a luxury automotive brand
 - [**Hyundai** (infotainment)](https://www.hyundai.com/wsvc/ww/download.file.do?id=/content/hyundai/ww/data/opensource/data/GN7-2022/licenseCode/info), a global automotive brand
 - [**Kia** (infotainment)](http://webmanual.kia.com/PREM_GEN6/AVNT/RJPE/KOR/Korean/reference010.html), a global automotive brand
 - [**Mercedes-Benz Operating System (MB.OS)**](https://group.mercedes-benz.com/careers/about-us/mercedes-benz-operating-system/), a core component of the vehicle software ecosystem from Mercedes-Benz
+- [**NVIDIA DRIVE OS**](https://developer.nvidia.com/docs/drive/drive-os/6.0.5/public/driveworks-nvcgf/dwx_open_source_attribution.html), the operating system and DriveWorks SDK powering NVIDIA's platform for autonomous vehicles
 - [**Rivian** (infotainment)](https://assets.ctfassets.net/2md5qhoeajym/3cwyo4eoufk4yingUwusFt/ded2c47da620fdfc99c88c7156d2c1d8/In-Vehicle_OSS_Attribution_2024__11-24_.pdf), an electric vehicle manufacturer
 - [**Suzuki** (infotainment)](https://www.globalsuzuki.com/motorcycle/ipc/oss/oss_48KA_00.pdf), a global automotive and motorcycle manufacturer

 ## Gaming and Entertainment

+- [**Anno 117: Pax Romana**](https://www.mobygames.com/person/1195889/niels-lohmann/credits/), a city-building strategy game set in the Roman Empire
 - [**Assassin's Creed: Mirage**](https://www.mobygames.com/person/1195889/niels-lohmann/credits/), a stealth-action game set in the Middle East, focusing on the journey of a young assassin with classic parkour and stealth mechanics
+- [**Battlefield 6**](https://www.mobygames.com/person/1195889/niels-lohmann/credits/), a military first-person shooter known for its large-scale multiplayer battles
+- [**Battlefield: REDSEC**](https://www.mobygames.com/person/1195889/niels-lohmann/credits/), a free-to-play battle royale experience set in the Battlefield universe
+- [**BioMenace: Remastered**](https://www.mobygames.com/person/1195889/niels-lohmann/credits/), a remaster of the classic side-scrolling platform shooter
 - [**Chasm: The Rift**](https://www.mobygames.com/person/1195889/niels-lohmann/credits/), a first-person shooter blending horror and adventure, where players navigate dark realms and battle monsters
 - [**College Football 25**](https://www.mobygames.com/person/1195889/niels-lohmann/credits/), a college football simulation game featuring gameplay that mimics real-life college teams and competitions
+- [**College Football 26**](https://www.mobygames.com/person/1195889/niels-lohmann/credits/), a college football simulation game featuring licensed teams and stadiums
+- [**College Football 27**](https://www.mobygames.com/person/1195889/niels-lohmann/credits/), the latest installment of the college football simulation series
 - [**Concepts**](https://concepts.app/en/licenses), a digital sketching app designed for creative professionals, offering flexible drawing tools for illustration, design, and brainstorming
 - [**Depthkit**](https://www.depthkit.tv/third-party-licenses), a tool for creating and capturing volumetric video, enabling immersive 3D experiences and interactive content
+- [**Dune: Awakening**](https://www.mobygames.com/person/1195889/niels-lohmann/credits/), an open-world survival MMO set on the desert planet Arrakis
+- [**EA Sports FC 25**](https://www.mobygames.com/person/1195889/niels-lohmann/credits/), an association football simulation with club, career, and online modes
+- [**EA Sports FC 26**](https://www.mobygames.com/person/1195889/niels-lohmann/credits/), the latest installment of the association football simulation series
+- [**EA Sports UFC 6**](https://www.mobygames.com/person/1195889/niels-lohmann/credits/), a mixed martial arts fighting simulation
+- [**FiveM**](https://github.com/citizenfx/fivem), a modification framework for Grand Theft Auto V that powers custom multiplayer servers
+- [**FLUX:: Immersive**](https://doc.flux.audio/syrah/Credits.html), a suite of professional audio processing and immersive mixing plugins used in music and post-production
 - [**IMG.LY**](https://img.ly/acknowledgements), a platform offering creative tools and SDKs for integrating advanced image and video editing in applications
+- [**immersivetech**](https://immersitech.io/open-source-third-party-software/), a technology company focused on immersive experiences, providing tools and solutions for virtual and augmented reality applications
+- [**Kodi**](https://github.com/xbmc/xbmc/blob/master/xbmc/utils/JSONVariantWriter.cpp), a home theater and media center application
 - [**LOOT**](https://loot.readthedocs.io/_/downloads/en/0.13.0/pdf/), a tool for optimizing the load order of game plugins, commonly used in The Elder Scrolls and Fallout series
+- [**LunaTranslator**](https://github.com/HIllya51/LunaTranslator/blob/main/src/NativeImpl/LunaSubprocess/aspatch.cpp), a real-time translation tool for visual novels
+- [**MaaAssistantArknights**](https://github.com/MaaAssistantArknights/MaaAssistantArknights/blob/dev-v2/src/MaaCore/Vision/Roguelike/BlackFlow/BlackFlowMapAnalyzer.cpp), an automation assistant for the mobile game Arknights
 - [**Madden NFL 25**](https://www.mobygames.com/person/1195889/niels-lohmann/credits/), a sports simulation game capturing the excitement of American football with realistic gameplay and team management features
+- [**Madden NFL 26**](https://www.mobygames.com/person/1195889/niels-lohmann/credits/), an American football simulation with franchise and team management modes
+- [**Madden NFL 27**](https://www.mobygames.com/person/1195889/niels-lohmann/credits/), the latest installment of the American football simulation series
 - [**Marne**](https://marne.io/licenses), an unofficial private server platform for hosting custom Battlefield 1 game experiences
 - [**Minecraft**](https://www.minecraft.net/zh-hant/attribution), a popular sandbox video game
+- [**Mumble**](https://github.com/mumble-voip/mumble), a low-latency, open-source voice chat application widely used by gaming communities
 - [**NHL 22**](https://www.mobygames.com/person/1195889/niels-lohmann/credits/), a hockey simulation game offering realistic gameplay, team management, and various modes to enhance the hockey experience
+- [**OBS Studio**](https://github.com/obsproject/obs-studio), a free and open-source suite for video recording and live streaming
+- [**OpenRCT2**](https://github.com/OpenRCT2/OpenRCT2/blob/develop/src/openrct2/core/JsonFwd.hpp), an open source re-implementation of RollerCoaster Tycoon 2
 - [**Pixelpart**](https://pixelpart.net/documentation/book/third-party.html), a 2D animation and video compositing software that allows users to create animated graphics and visual effects with a focus on simplicity and ease of use
 - [**Razer Cortex**](https://mysupport.razer.com/app/answers/detail/a_id/14146/~/open-source-software-for-razer-software), a gaming performance optimizer and system booster designed to enhance the gaming experience
 - [**Red Dead Redemption II**](https://www.mobygames.com/person/1195889/niels-lohmann/credits/), an open-world action-adventure game following an outlaw's story in the late 1800s, emphasizing deep storytelling and immersive gameplay
+- [**RetroArch**](https://github.com/libretro/RetroArch), a frontend for emulators, game engines, and media players built on the libretro API
+- [**shadPS4**](https://github.com/shadps4-emu/shadPS4/blob/main/src/core/user_manager.h), a PlayStation 4 emulator for Windows, Linux and macOS
+- [**skate.**](https://www.mobygames.com/person/1195889/niels-lohmann/credits/), a free-to-play skateboarding game set in an open world
 - [**Snapchat**](https://www.snap.com/terms/license-android), a multimedia messaging and augmented reality app for communication and entertainment
+- [**Steel Century Groove**](https://www.mobygames.com/person/1195889/niels-lohmann/credits/), an action game released in 2026
+- [**Sunshine**](https://github.com/LizardByte/Sunshine/blob/master/src/confighttp.h), a self-hosted game streaming host compatible with Moonlight clients
 - [**Tactics Ogre: Reborn**](https://www.square-enix-games.com/en_US/documents/tactics-ogre-reborn-pc-installer-software-and-associated-plug-ins-disclosure), a tactical role-playing game featuring strategic battles and deep storytelling elements
 - [**Throne and Liberty**](https://www.amazon.com/gp/help/customer/display.html?nodeId=T7fLNw5oAevCMtJFPj&pop-up=1), an MMORPG that offers an expansive fantasy world with dynamic gameplay and immersive storytelling
 - [**Unity Vivox**](https://docs.unity3d.com/Packages/com.unity.services.vivox@15.1/license/Third%20Party%20Notices.html), a communication service that enables voice and text chat functionality in multiplayer games developed with Unity
+- [**xemu**](https://github.com/xemu-project/xemu), an emulator of the original Xbox console
 - [**Zool: Redimensioned**](https://www.mobygames.com/person/1195889/niels-lohmann/credits/), a modern reimagining of the classic platformer featuring fast-paced gameplay and vibrant environments
- [**immersivetech**](https://immersitech.io/open-source-third-party-software/), a technology company focused on immersive experiences, providing tools and solutions for virtual and augmented reality applications

 ## Consumer Electronics

@@ -50,109 +81,195 @@ the result of an internet search. If you know further customers of the library,
 - [**Canon CanoScan LIDE**](https://carolburo.com/wp-content/uploads/2024/06/LiDE400_OnlineManual_Win_FR_V02.pdf), a series of flatbed scanners offering high-resolution image scanning for home and office use
 - [**Canon PIXMA Printers**](https://www.mediaexpert.pl/products/files/73/7338196/Instrukcja-obslugi-CANON-Pixma-TS7450i.pdf), a line of all-in-one inkjet printers known for high-quality printing and wireless connectivity
 - [**Cisco Webex Desk Camera**](https://www.cisco.com/c/dam/en_us/about/doing_business/open_source/docs/CiscoWebexDeskCamera-23-1622100417.pdf), a video camera designed for professional-quality video conferencing and remote collaboration
+- [**DJI Edge SDK**](https://github.com/dji-sdk/Edge-SDK-V2-Demo), the reference applications for DJI's Edge SDK, used to build edge computing services on DJI drone docks
+- [**Elgato Stream Deck**](https://github.com/elgatosf/streamdeck-obs-plugin2), a family of programmable control surfaces for content creators and their plugin ecosystem
+- [**Instagrid**](https://instagrid.co/intellectual-property/foss), a manufacturer of portable, high-performance battery systems for professional mobile power supply
+- [**iRobot**](https://iot-content.irobot.com/iw/sfsites/c/cms/delivery/media/MCKRLTPDJSSJBNJKDA5SG5UVVIIQ), a manufacturer of autonomous home robots including the Roomba vacuum cleaner range
+- [**Logitech Logi Bolt**](https://opensource.logitech.com/wiki/Logi_BoltApp/), the management application for Logitech's secure wireless connectivity technology
+- [**Novitus**](https://novitus.pl/licencjepensource), a manufacturer of fiscal cash registers and point-of-sale devices
 - [**Philips Hue Personal Wireless Lighting**](http://2ak5ape.257.cz/), a smart lighting system for customizable and wireless home illumination
 - [**Ray-Ban Meta Smart glasses**](https://www.meta.com/de/en/legal/smart-glasses/third-party-notices-android/03/), a pair of smart glasses designed for capturing photos and videos with integrated connectivity and social features
 - [**Razer Synapse**](https://mysupport.razer.com/app/answers/detail/a_id/14146/~/open-source-software-for-razer-software), a unified configuration software enabling hardware customization for Razer devices
+- [**Sharp Professional Displays**](https://jp.sharp/restricted/business/lcd-display/cms/images/source_pnla862/PN-LA652_752_862_LicenseInformation.pdf), a range of large-format interactive displays for business and education
 - [**Siemens SINEMA Remote Connect**](https://cache.industry.siemens.com/dl/files/790/109793790/att_1054961/v2/OSS_SINEMA-RC_86.pdf), a remote connectivity solution for monitoring and managing industrial networks and devices securely
+- [**Skydio**](https://pages.skydio.com/rs/784-TUF-591/images/Open%20Source%20Software%20Notice%20v0.2.html), a manufacturer of autonomous drones for inspection, public safety, and defense applications
 - [**Sony PlayStation 4**](https://doc.dl.playstation.net/doc/ps4-oss/index.html), a gaming console developed by Sony that offers a wide range of games and multimedia entertainment features
+- [**Sony Spatial Reality Display**](https://www.sony.co.jp/en/Products/Developer-Spatial-Reality-display/download/dcc-tools/blender-plugin/SpatiaRealityDisplayPluginforPreviewBL_Manual.pdf), a glasses-free stereoscopic 3D display and its plugins for Blender, 3ds Max, and ZBrush
 - [**Sony Virtual Webcam Driver for Remote Camera**](https://helpguide.sony.net/rc/vwd/v1/zh-cn/print.pdf), a software driver that enables the use of Sony cameras as virtual webcams for video conferencing and streaming
+- [**Yamaha Clavinova**](https://usa.yamaha.com/files/download/other_assets/1/2298171/CLP-800_oss_license.pdf), a series of digital pianos combining acoustic piano feel with digital sound technology

-## Operating Systems
+## Operating Systems and Platforms

 - [**Apple iOS and macOS**](https://www.apple.com/macos), a family of operating systems developed by Apple, including iOS for mobile devices and macOS for desktop computers
+- [**Chromium**](https://chromium.googlesource.com/chromium/src/+/main/third_party/nlohmann_json/), the open-source browser project that Google Chrome, Microsoft Edge, and many other browsers are built on, where the library is used as data container for on-device model execution
 - [**Google Fuchsia**](https://fuchsia.googlesource.com/third_party/json/), an open-source operating system developed by Google, designed to be secure, updatable, and adaptable across various devices
+- [**LG webOS**](https://github.com/webosose/com.webos.service.camera), a Linux-based operating system used in LG smart TVs, signage, and embedded devices
+- [**Microsoft Azure Linux**](https://github.com/microsoft/azurelinux), a Linux distribution developed by Microsoft for Azure infrastructure and edge workloads
+- [**OpenHarmony**](https://github.com/openharmony/third_party_json), an open-source operating system for smart devices and the foundation of HarmonyOS
 - [**SerenityOS**](https://github.com/SerenityOS/serenity), an open-source operating system that aims to provide a simple and beautiful user experience with a focus on simplicity and elegance
+- [**Windows Subsystem for Linux**](https://github.com/microsoft/WSL), a compatibility layer that runs Linux environments natively on Windows
 - [**Yocto**](http://ftp.emacinc.com/openembedded-sw/kirkstone-icop-5.15-kirkstone-6.0/archive-2024-10/pn8m-090t-ppc/licenses/nlohmann-json/), a Linux-based build system for creating custom operating systems and software distributions, tailored for embedded devices and IoT applications

 ## Development Tools and IDEs

 - [**Accentize SpectralBalance**](https://www.accentize.com/products/SpectralBalanceManual.pdf), an adaptive speech analysis tool designed to enhance audio quality by optimizing frequency balance in recordings
+- [**Airbus Ghidralligator**](https://www.cyber.airbus.com/en/newsroom/stories/2025-06-ghidralligator), a Ghidra-based emulator from Airbus CyberSecurity used to fuzz and analyse embedded firmware
+- [**Apache brpc**](https://github.com/apache/brpc/blob/master/src/butil/iobuf.h), an industrial-grade remote procedure call framework for C++
 - [**Arm Compiler for Linux**](https://documentation-service.arm.com/static/66558e9d876c8d213b7843e4), a software development toolchain for compiling and optimizing applications on Arm-based Linux systems
 - [**BBEdit**](https://s3.amazonaws.com/BBSW-download/BBEdit_15.1.2_User_Manual.pdf), a professional text and code editor for macOS
 - [**CoderPad**](https://coderpad.io), a collaborative coding platform that enables real-time code interviews and assessments for developers; the library is included in every CoderPad instance and can be accessed with a simple `#include "json.hpp"`
+- [**Codon**](https://github.com/exaloop/codon/blob/develop/jupyter/jupyter.h), an ahead-of-time compiler for a Python-like language
 - [**Compiler Explorer**](https://godbolt.org), a web-based tool that allows users to write, compile, and visualize the assembly output of code in various programming languages; the library is readily available and accessible with the directive `#include <nlohmann/json.hpp>`.
- [**GitHub CodeQL**](https://github.com/github/codeql), a code analysis tool used for identifying security vulnerabilities and bugs in software through semantic queries
+- [**Flutter**](https://github.com/flutter/flutter/blob/master/engine/src/flutter/impeller/compiler/reflector.cc), a UI toolkit for building natively compiled applications for mobile, web, and desktop from a single codebase
+- [**Fraunhofer VVenC**](https://github.com/fraunhoferhhi/vvenc), a fast and efficient encoder for the Versatile Video Coding (H.266/VVC) standard
+- [**GitHub CodeQL**](https://github.com/github/codeql/blob/main/shared/cpp/Diagnostics.h), a code analysis tool used for identifying security vulnerabilities and bugs in software through semantic queries
+- [**GoPro ngfx**](https://github.com/gopro/ngfx), a low-level graphics abstraction and profiling framework developed by GoPro
+- [**gRPC**](https://github.com/grpc/grpc/blob/master/tools/artifact_gen/utils.h), a high-performance universal remote procedure call framework
 - [**Hex-Rays**](https://docs.hex-rays.com/user-guide/user-interface/licenses), a reverse engineering toolset for analyzing and decompiling binaries, primarily used for security research and vulnerability analysis
 - [**ImHex**](https://github.com/WerWolv/ImHex), a hex editor designed for reverse engineering, providing advanced features for data analysis and manipulation
+- [**Intel GITS**](https://github.com/intel/gits), a tool for capturing and replaying graphics API calls for debugging and performance analysis
 - [**Intel GPA Framework**](https://intel.github.io/gpasdk-doc/src/licenses.html), a suite of cross-platform tools for capturing, analyzing, and optimizing graphics applications across different APIs
 - [**Intopix**](https://www.intopix.com/software-licensing), a provider of advanced image processing and compression solutions used in software development and AV workflows
 - [**Java SE**](https://www.oracle.com/a/tech/docs/jdk8-lium.pdf), the core Java platform that provides the libraries and runtime needed to build and run general-purpose Java applications
- [**MKVToolNix**](https://mkvtoolnix.download/doc/README.md), a set of tools for creating, editing, and inspecting MKV (Matroska) multimedia container files
 - [**Meta Yoga**](https://github.com/facebook/yoga), a layout engine that facilitates flexible and efficient user interface design across multiple platforms
- [**NVIDIA Nsight Compute**](https://docs.nvidia.com/nsight-compute/2022.2/pdf/CopyrightAndLicenses.pdf), a performance analysis tool for CUDA applications that provides detailed insights into GPU performance metrics
+- [**MKVToolNix**](https://mkvtoolnix.download/doc/README.md), a set of tools for creating, editing, and inspecting MKV (Matroska) multimedia container files
+- [**MRTech IFF SDK**](https://mr-technologies.com/pub/iff-sdk-manual-2-0-1/iff-sdk-manual-2-0-1.pdf), an image processing SDK for machine vision applications with GPU-accelerated pipelines
+- [**Nix**](https://github.com/NixOS/nix/blob/master/src/nix/build.cc), a purely functional package manager
 - [**Notepad++**](https://github.com/notepad-plus-plus/notepad-plus-plus), a free source code editor that supports various programming languages
+- [**NVIDIA Nsight Compute**](https://docs.nvidia.com/nsight-compute/2022.2/pdf/CopyrightAndLicenses.pdf), a performance analysis tool for CUDA applications that provides detailed insights into GPU performance metrics
+- [**openFrameworks**](https://github.com/openframeworks/openFrameworks/blob/master/libs/openFrameworks/utils/ofJson.h), a community-developed C++ toolkit for creative coding
 - [**OpenRGB**](https://gitlab.com/CalcProgrammer1/OpenRGB), an open source RGB lighting control that doesn't depend on manufacturer software
 - [**OpenTelemetry C++**](https://github.com/open-telemetry/opentelemetry-cpp), a library for collecting and exporting observability data in C++, enabling developers to implement distributed tracing and metrics in their application
+- [**Oracle GraalVM**](https://docs.oracle.com/en/graalvm/jdk/21/docs/licensing-information/), a high-performance JDK distribution with ahead-of-time compilation and polyglot runtime support
+- [**Philips amp-cucumber-cpp-runner**](https://github.com/philips-software/amp-cucumber-cpp-runner), a behaviour-driven development test runner for embedded C++ software developed at Philips
 - [**Qt Creator**](https://doc.qt.io/qtcreator/qtcreator-attribution-json-nlohmann.html), an IDE for developing applications using the Qt application framework
+- [**Qt for MCUs**](https://doc.qt.io/QtForMCUs/quickultralite-attribution-nlohmann-json.html), a graphics framework for building fluid user interfaces on microcontrollers
+- [**React Native**](https://github.com/react/react-native/blob/main/packages/react-native/ReactCxxPlatform/react/devsupport/PackagerConnection.cpp), a framework for building native mobile applications using React
 - [**Scanbot SDK**](https://docs.scanbot.io/barcode-scanner-sdk/web/third-party-libraries/), a software development kit (SDK) that provides tools for integrating advanced document scanning and barcode scanning capabilities into applications
+- [**STMicroelectronics TouchGFX**](https://www.st.com/resource/en/additional_license_terms/additional-license-terms-x-cube-touchgfx.html), a graphical user interface framework shipped with STM32 microcontrollers for building embedded HMIs
+- [**swagger-codegen**](https://github.com/swagger-api/swagger-codegen/blob/master/samples/server/petstore/pistache-server/model/Pet.h), a template-driven engine that generates API clients and server stubs from an OpenAPI specification
+- [**Swoole**](https://github.com/swoole/swoole-src/blob/master/ext-src/swoole_admin_server.cc), a coroutine-based concurrency engine for PHP
+- [**Tracy Profiler**](https://github.com/wolfpld/tracy/blob/master/profiler/src/profiler/TracyLlm.hpp), a real-time frame profiler for games and other applications
+- [**WasmEdge**](https://github.com/WasmEdge/WasmEdge/blob/master/plugins/wasi_nn/GGML/tts/tts_core.cpp), a lightweight WebAssembly runtime for edge and cloud workloads
+- [**x64dbg**](https://github.com/x64dbg/x64dbg/blob/development/src/cross/remote_table/TableRpcData.h), an open source user mode debugger for Windows, aimed at reverse engineering and malware analysis

 ## Machine Learning and AI

+- [**Alibaba MNN**](https://github.com/alibaba/MNN), a lightweight deep learning inference engine for mobile and embedded devices
+- [**AMD Gaia**](https://github.com/amd/gaia), an open-source framework for running generative AI applications locally on AMD hardware
+- [**AMD Vitis AI (VAIP)**](https://github.com/amd/vaip), the execution provider stack that runs AI models on AMD Ryzen AI and adaptive computing devices
 - [**Apple Core ML Tools**](https://github.com/apple/coremltools), a set of tools for converting and configuring machine learning models for deployment in Apple's Core ML framework
 - [**Avular Mobile Robotics**](https://www.avular.com/licenses/nlohmann-json-3.9.1.txt), a platform for developing and deploying mobile robotics solutions
+- [**FunASR**](https://github.com/modelscope/FunASR/blob/main/runtime/http/bin/asr_sessions.h), a speech recognition toolkit for training and deploying end-to-end models
 - [**Google gemma.cpp**](https://github.com/google/gemma.cpp), a lightweight C++ inference engine designed for running AI models from the Gemma family
+- [**Google Magenta The Infinite Crate**](https://github.com/magenta/the-infinite-crate), an open-source generative AI plugin for digital audio workstations from Google's Magenta research team
+- [**GPT4All**](https://github.com/nomic-ai/gpt4all/blob/main/gpt4all-chat/src/tool.h), a desktop application for running local large language models on consumer hardware
+- [**Huawei MindSpore**](https://github.com/mindspore-ai/mindspore/blob/master/Third_Party_Open_Source_Software_Notice), a deep learning framework for training and inference across device, edge, and cloud
+- [**KTransformers**](https://github.com/kvcache-ai/ktransformers/blob/main/archive/csrc/balance_serve/sched/model_config.h), a framework for heterogeneous large language model inference
 - [**llama.cpp**](https://github.com/ggerganov/llama.cpp), a C++ library designed for efficient inference of large language models (LLMs), enabling streamlined integration into applications
+- [**LocalAI**](https://github.com/mudler/LocalAI/blob/master/backend/cpp/ds4/dsml_renderer.cpp), a self-hosted inference engine that exposes local models through an OpenAI-compatible API
 - [**MLX**](https://github.com/ml-explore/mlx), an array framework for machine learning on Apple Silicon
 - [**Mozilla llamafile**](https://github.com/Mozilla-Ocho/llamafile), a tool designed for distributing and executing large language models (LLMs) efficiently using a single file format
 - [**NVIDIA ACE**](https://docs.nvidia.com/ace/latest/index.html), a suite of real-time AI solutions designed for the development of interactive avatars and digital human applications, enabling scalable and sophisticated user interactions
+- [**NVIDIA Instant NGP**](https://github.com/NVlabs/instant-ngp/blob/master/src/nerf_loader.cu), an implementation of instant neural graphics primitives for rapid scene reconstruction
+- [**NVIDIA TensorRT**](https://github.com/NVIDIA/TensorRT), an SDK for high-performance deep learning inference, including its TensorRT-LLM extension for large language models
+- [**NVIDIA TensorRT-LLM**](https://github.com/NVIDIA/TensorRT-LLM/blob/main/cpp/tensorrt_llm/common/safetensors.cpp), a toolkit for optimizing and serving large language model inference on GPUs
+- [**ONNX Runtime**](https://github.com/microsoft/onnxruntime), a cross-platform inference and training accelerator for machine learning models
+- [**OpenVINO**](https://github.com/openvinotoolkit/openvino), Intel's toolkit for optimizing and deploying deep learning inference across CPUs, GPUs, and NPUs
+- [**PaddleOCR**](https://github.com/PaddlePaddle/PaddleOCR/blob/main/deploy/cpp_infer/src/modules/text_detection/result.cc), an optical character recognition toolkit that turns documents and images into structured data
+- [**PaddlePaddle**](https://github.com/PaddlePaddle/Paddle/blob/develop/paddle/ap/src/axpr/anf_expr.cc), a deep learning framework for distributed training and inference
 - [**Peer**](https://support.peer.inc/hc/en-us/articles/17261335054235-Licenses), a platform offering personalized AI assistants for interactive learning and creative collaboration
+- [**PyTorch**](https://github.com/pytorch/pytorch), a machine learning framework for building and training neural networks, widely used in research and production
+- [**Qualcomm AI Engine Direct**](https://github.com/qualcomm/qai-appbuilder), a toolchain for building and running generative AI applications on Snapdragon devices
+- [**sherpa-onnx**](https://github.com/k2-fsa/sherpa-onnx/blob/master/sherpa-onnx/csrc/sentence-piece-tokenizer.cc), a speech toolkit for on-device recognition, synthesis and speaker diarization
 - [**stable-diffusion.cpp**](https://github.com/leejet/stable-diffusion.cpp), a C++ implementation of the Stable Diffusion image generation model
 - [**TanvasTouch**](https://tanvas.co/tanvastouch-sdk-third-party-acknowledgments), a software development kit (SDK) that enables developers to create tactile experiences on touchscreens, allowing users to feel textures and physical sensations in a digital environment
 - [**TensorFlow**](https://github.com/tensorflow/tensorflow), a machine learning framework that facilitates the development and training of models, supporting data serialization and efficient data exchange between components
+- [**whisper.cpp**](https://github.com/ggml-org/whisper.cpp), a C++ implementation of OpenAI's Whisper automatic speech recognition model

 ## Scientific Research and Analysis

 - [**BLACK**](https://www.black-sat.org/en/stable/installation/linux.html), a bounded linear temporal logic (LTL) satisfiability checker
+- [**CERN ALICE O2**](https://github.com/AliceO2Group/AliceO2), the online-offline computing framework of the ALICE heavy-ion experiment at the Large Hadron Collider
 - [**CERN Atlas Athena**](https://gitlab.cern.ch/atlas/athena/-/blob/main/Control/PerformanceMonitoring/PerfMonComps/src/PerfMonMTSvc.h), a software framework used in the ATLAS experiment at the Large Hadron Collider (LHC) for performance monitoring
+- [**CERN CMSSW**](https://github.com/cms-sw/cmssw), the offline software framework of the CMS experiment at the Large Hadron Collider
+- [**CERN Gaudi**](https://gitlab.cern.ch/gaudi/Gaudi), the event-processing framework used by the LHCb and ATLAS experiments at the Large Hadron Collider
 - [**ICU**](https://github.com/unicode-org/icu), the International Components for Unicode, a mature library for software globalization and multilingual support
 - [**KAMERA**](https://github.com/Kitware/kamera), a platform for synchronized data collection and real-time deep learning to map marine species like polar bears and seals, aiding Arctic ecosystem research
 - [**KiCad**](https://gitlab.com/kicad/code/kicad/-/tree/master/thirdparty/nlohmann_json), a free and open-source software suite for electronic design automation
+- [**LLNL ROSE**](https://github.com/llnl/rose), a compiler infrastructure from Lawrence Livermore National Laboratory for building source-to-source program analysis and transformation tools
 - [**Maple**](https://www.maplesoft.com/support/help/Maple/view.aspx?path=copyright), a symbolic and numeric computing environment for advanced mathematical modeling and analysis
 - [**MeVisLab**](https://mevislabdownloads.mevis.de/docs/current/MeVis/ThirdParty/Documentation/Publish/ThirdPartyReference/index.html), a software framework for medical image processing and visualization.
+- [**MITK**](https://github.com/MITK/MITK), the Medical Imaging Interaction Toolkit, a framework for developing interactive medical image processing software
 - [**OpenPMD API**](https://openpmd-api.readthedocs.io/en/0.8.0-alpha/backends/json.html), a versatile programming interface for accessing and managing scientific data, designed to facilitate the efficient storage, retrieval, and sharing of simulation data across various applications and platforms
+- [**ORNL DataFed**](https://github.com/ORNL/DataFed), a federated scientific data management system developed at Oak Ridge National Laboratory
 - [**ParaView**](https://github.com/Kitware/ParaView), an open-source tool for large-scale data visualization and analysis across various scientific domains
 - [**QGIS**](https://gitlab.b-data.ch/qgis/qgis/-/blob/backport-57658-to-release-3_34/external/nlohmann/json.hpp), a free and open-source geographic information system (GIS) application that allows users to create, edit, visualize, and analyze geospatial data across a variety of formats
- [**VTK**](https://github.com/Kitware/VTK), a software library for 3D computer graphics, image processing, and visualization
+- [**Sandia InterSpec**](https://github.com/sandialabs/InterSpec), spectral radiation analysis software from Sandia National Laboratories for identifying radioactive isotopes
 - [**VolView**](https://github.com/Kitware/VolView), a lightweight application for interactive visualization and analysis of 3D medical imaging data.
+- [**VTK**](https://github.com/Kitware/VTK), a software library for 3D computer graphics, image processing, and visualization

 ## Business and Productivity Software

 - [**ArcGIS PRO**](https://www.esri.com/content/dam/esrisites/en-us/media/legal/open-source-acknowledgements/arcgis-pro-2-8-attribution-report.html), a desktop geographic information system (GIS) application developed by Esri for mapping and spatial analysis
 - [**Autodesk Desktop**](https://damassets.autodesk.net/content/dam/autodesk/www/Company/legal-notices-trademarks/autodesk-desktop-platform-components/internal-autodesk-components-web-page-2023.pdf), a software platform developed by Autodesk for creating and managing desktop applications and services
 - [**Check Point**](https://www.checkpoint.com/about-us/copyright-and-trademarks/), a cybersecurity company specializing in threat prevention and network security solutions, offering a range of products designed to protect enterprises from cyber threats and ensure data integrity
+- [**EasyEffects**](https://github.com/wwmm/easyeffects/blob/master/src/presets_manager.hpp), an audio effects processor for PipeWire offering limiting, compression and equalization
+- [**espanso**](https://github.com/espanso/espanso/blob/dev/espanso-ui/src/win32/native.cpp), a cross-platform text expander
+- [**Karabiner-Elements**](https://github.com/pqrs-org/Karabiner-Elements/blob/main/src/share/app_icon.hpp), a keyboard customizer for macOS
+- [**MacType**](https://github.com/snowie2000/mactype/blob/directwrite/settings.h), a font rendering engine for Windows
+- [**magicplan**](https://help.magicplan.app/acknowledgments), a mobile application for creating floor plans and interior designs using augmented reality
 - [**Microsoft Office for Mac**](https://officecdnmac.microsoft.com/pr/legal/mac/OfficeforMacAttributions.html), a suite of productivity applications developed by Microsoft for macOS, including tools for word processing, spreadsheets, and presentations
 - [**Microsoft Teams**](https://www.microsoft.com/microsoft-teams/), a team collaboration application offering workspace chat and video conferencing, file storage, and integration of proprietary and third-party applications and services
+- [**MuseScore**](https://github.com/musescore/MuseScore), a free and open-source music notation and composition application
+- [**NanaZip**](https://github.com/M2Team/NanaZip/blob/main/NanaZip.Codecs/NanaZip.Codecs.Archive.ElectronAsar.cpp), a 7-Zip derivative built for modern Windows
 - [**Nexthink Infinity**](https://docs.nexthink.com/legal/services-terms/experience-open-source-software-licenses/infinity-2022.8-software-licenses), a digital employee experience management platform for monitoring and improving IT performance
 - [**Sophos Connect Client**](https://docs.sophos.com/nsg/licenses/SophosConnect/SophosConnectAttribution.html), a secure VPN client from Sophos that allows remote users to connect to their corporate network, ensuring secure access to resources and data
 - [**Stonebranch**](https://stonebranchdocs.atlassian.net/wiki/spaces/UA77/pages/799545647/Licenses+for+Third-Party+Libraries), a cloud-based cybersecurity solution that integrates backup, disaster recovery, and cybersecurity features to protect data and ensure business continuity for organizations
 - [**Tablecruncher**](https://tablecruncher.com/), a data analysis tool that allows users to import, analyze, and visualize spreadsheet data, offering interactive features for better insights and decision-making
- [**magicplan**](https://help.magicplan.app/acknowledgments), a mobile application for creating floor plans and interior designs using augmented reality
+- [**VNote**](https://github.com/vnotex/vnote/blob/master/src/core/services/notebookcoreservice.cpp), a Markdown-based note-taking application written in C++

 ## Databases and Big Data

 - [**ADIOS2**](https://code.ornl.gov/ecpcitest/adios2/-/tree/pr4285_FFSUpstream/thirdparty/nlohmann_json?ref_type=heads), a data management framework designed for high-performance input and output operations
+- [**Apache Doris**](https://github.com/apache/doris/blob/master/be/src/runtime/be_proc_monitor.cpp), a real-time analytical database for high-concurrency queries
+- [**Claris FileMaker Server**](https://www.claris.com/company/legal/docs/acknowledgements/filemaker-server-macwin/claris_fms2025_acknowledgements_en.pdf), the server platform hosting FileMaker custom apps and databases, developed by Apple subsidiary Claris
+- [**ClickHouse**](https://github.com/ClickHouse/ClickHouse), a column-oriented database management system for real-time analytical queries
 - [**Cribl Stream**](https://docs.cribl.io/stream/third-party-current-list/), a real-time data processing platform that enables organizations to collect, route, and transform observability data, enhancing visibility and insights into their systems
 - [**DB Browser for SQLite**](https://github.com/sqlitebrowser/sqlitebrowser), a visual open-source tool for creating, designing, and editing SQLite database files
+- [**Manticore Search**](https://github.com/manticoresoftware/manticoresearch/blob/main/src/searchdhttpcompat.cpp), a database for search, offering full-text and vector queries
+- [**Milvus**](https://github.com/milvus-io/milvus/blob/master/internal/core/src/query/PlanImpl.h), a cloud-native vector database built for embedding similarity search
+- [**MongoDB**](https://github.com/mongodb/mongo/blob/master/src/mongo/replay/config_handler.cpp), a general-purpose document database
 - [**MySQL Connector/C++**](https://docs.oracle.com/cd/E17952_01/connector-cpp-9.1-license-com-en/license-opentelemetry-cpp-com.html), a C++ library for connecting and interacting with MySQL databases
 - [**MySQL NDB Cluster**](https://downloads.mysql.com/docs/licenses/cluster-9.0-com-en.pdf), a distributed database system that provides high availability and scalability for MySQL databases
 - [**MySQL Shell**](https://downloads.mysql.com/docs/licenses/mysql-shell-8.0-gpl-en.pdf), an advanced client and code editor for interacting with MySQL servers, supporting SQL, Python, and JavaScript
- [**PrestoDB**](https://github.com/prestodb/presto), a distributed SQL query engine designed for large-scale data analytics, originally developed by Facebook
+- [**PrestoDB**](https://github.com/prestodb/presto/blob/master/presto-native-execution/presto_cpp/main/Announcer.cpp), a distributed SQL query engine designed for large-scale data analytics, originally developed by Facebook
 - [**ROOT Data Analysis Framework**](https://root.cern/doc/v614/classnlohmann_1_1basic__json.html), an open-source data analysis framework widely used in high-energy physics and other fields for data processing and visualization
+- [**Typesense**](https://github.com/typesense/typesense/blob/v31/include/join.h), an open source typo-tolerant search engine
+- [**Vearch**](https://github.com/jd-opensource/vearch), a distributed vector database developed at JD.com for similarity search and retrieval-augmented generation
 - [**WiredTiger**](https://github.com/wiredtiger/wiredtiger), a high-performance storage engine for databases, offering support for compression, concurrency, and checkpointing

 ## Simulation and Modeling

+- [**Adobe Lagrange**](https://github.com/adobe/lagrange), a geometry processing library developed by Adobe for mesh manipulation and analysis
 - [**Arcturus HoloSuite**](https://www.datocms-assets.com/104353/1698904597-holosuite-third-party-software-credits-and-attributions-2.pdf), a software toolset for capturing, editing, and streaming volumetric video, featuring advanced compression technologies for high-quality 3D content creation
 - [**azul**](https://pure.tudelft.nl/ws/files/85338589/tgis.12673.pdf), a fast and efficient 3D city model viewer designed for visualizing urban environments and spatial data
+- [**Bambu Studio**](https://github.com/bambulab/BambuStudio), a slicing and print management application for Bambu Lab 3D printers
 - [**Blender**](https://projects.blender.org/blender/blender/search?q=nlohmann), a free and open-source 3D creation suite for modeling, animation, rendering, and more
 - [**cpplot**](https://cpplot.readthedocs.io/en/latest/library_api/function_eigen_8h_1ac080eac0541014c5892a55e41bf785e6.html), a library for creating interactive graphs and charts in C++, which can be viewed in web browsers
 - [**Foundry Nuke**](https://learn.foundry.com/nuke/content/misc/studio_third_party_libraries.html), a powerful node-based digital compositing and visual effects application used in film and television post-production
+- [**FreeCAD**](https://github.com/FreeCAD/FreeCAD), a free and open-source parametric 3D CAD modeler for product design and engineering
 - [**GAMS**](https://www.gams.com/47/docs/THIRDPARTY.html), a high-performance mathematical modeling system for optimization and decision support
+- [**Keysight WirelessPro**](https://docs.keysight.com/display/engdocwirelesspro/WirelessPro+2026+Release+Notes), a simulation platform for 5G, 5G-Advanced, and 6G cellular network research
 - [**Kitware SMTK**](https://github.com/Kitware/SMTK), a software toolkit for managing simulation models and workflows in scientific and engineering applications
 - [**M-Star**](https://docs.mstarcfd.com/3_Licensing/thirdparty-licenses.html), a computational fluid dynamics software for simulating and analyzing fluid flow
 - [**MapleSim CAD Toolbox**](https://www.maplesoft.com/support/help/MapleSim/view.aspx?path=CADToolbox/copyright), a software extension for MapleSim that integrates CAD models, allowing users to import, manipulate, and analyze 3D CAD data within the MapleSim environment for enhanced modeling and simulation
+- [**Microsoft AirSim**](https://github.com/microsoft/AirSim/blob/main/AirLib/include/common/Settings.hpp), a simulator for autonomous vehicles and drones built on Unreal Engine
 - [**NVIDIA Omniverse**](https://docs.omniverse.nvidia.com/composer/latest/common/product-licenses/usd-explorer/usd-explorer-2023.2.0-licenses-manifest.html), a platform for 3D content creation and collaboration that enables real-time simulations and interactive experiences across various industries
+- [**OpenSCAD**](https://github.com/openscad/openscad/blob/master/src/core/AIClient.cc), a script-driven solid 3D CAD modeller
+- [**OrcaSlicer**](https://github.com/SoftFever/OrcaSlicer), an open-source slicer supporting a wide range of consumer 3D printers
 - [**Pixar Renderman**](https://rmanwiki-26.pixar.com/space/REN26/19662083/Legal+Notice), a photorealistic 3D rendering software developed by Pixar, widely used in the film industry for creating high-quality visual effects and animations
+- [**PrusaSlicer**](https://github.com/prusa3d/PrusaSlicer), the slicing software developed by Prusa Research for its 3D printers
 - [**ROS - Robot Operating System**](http://docs.ros.org/en/noetic/api/behaviortree_cpp/html/json_8hpp_source.html), a set of software libraries and tools that assist in developing robot applications
 - [**UBS**](https://www.ubs.com/), a multinational financial services and banking company

@@ -161,18 +278,31 @@ the result of an internet search. If you know further customers of the library,
 - [**Acronis Cyber Protect Cloud**](https://care.acronis.com/s/article/59533-Third-party-software-used-in-Acronis-Cyber-Protect-Cloud?language=en_US), an all-in-one data protection solution that combines backup, disaster recovery, and cybersecurity to safeguard business data from threats like ransomware
 - [**Baereos**](https://gitlab.tiger-computing.co.uk/packages/bareos/-/blob/tiger/bullseye/third-party/CLI11/examples/json.cpp), a backup solution that provides data protection and recovery options for various environments, including physical and virtual systems
 - [**Bitdefender Home Scanner**](https://www.bitdefender.de/site/Main/view/home-scanner-open-source.html), a tool from Bitdefender that scans devices for malware and security threats, providing a safeguard against potential online dangers
+- [**Cisco MLS++**](https://github.com/cisco/mlspp), an implementation of the Messaging Layer Security protocol for end-to-end encrypted group messaging
 - [**Citrix Provisioning**](https://docs.citrix.com/en-us/provisioning/2203-ltsr/downloads/pvs-third-party-notices-2203.pdf), a solution that streamlines the delivery of virtual desktops and applications by allowing administrators to manage and provision resources efficiently across multiple environments
 - [**Citrix Virtual Apps and Desktops**](https://docs.citrix.com/en-us/citrix-virtual-apps-desktops/2305/downloads/third-party-notices-apps-and-desktops.pdf), a solution from Citrix that delivers virtual apps and desktops
 - [**Cyberarc**](https://docs.cyberark.com/Downloads/Legal/Privileged%20Session%20Manager%20for%20SSH%20Third-Party%20Notices.pdf), a security solution that specializes in privileged access management, enabling organizations to control and monitor access to critical systems and data, thereby enhancing overall cybersecurity posture
+- [**Deutsche Telekom sysrepo-plugins**](https://github.com/telekom/sysrepo-plugins), a collection of YANG datastore plugins used to manage network devices
 - [**Egnyte Desktop**](https://helpdesk.egnyte.com/hc/en-us/articles/360007071732-Third-Party-Software-Acknowledgements), a secure cloud storage solution designed for businesses, enabling file sharing, collaboration, and data management across teams while ensuring compliance and data protection
 - [**Elster**](https://www.secunet.com/en/about-us/press/article/elstersecure-bietet-komfortablen-login-ohne-passwort-dank-secunet-protect4use), a digital platform developed by German tax authorities for secure and efficient electronic tax filing and management using secunet protect4use
+- [**Envoy**](https://github.com/envoyproxy/envoy), a cloud-native edge and service proxy that forms the data plane of many service meshes
 - [**Ethereum Solidity**](https://github.com/ethereum/solidity), a high-level, object-oriented programming language designed for implementing smart contracts on the Ethereum platform
+- [**gVisor**](https://github.com/google/gvisor), an application kernel that provides a secure sandbox for running untrusted containers
+- [**IBM Storage Virtualize**](https://public.dhe.ibm.com/systems/support/warranty/pdfs/stgoilc/SV_for_FS_7300_v8_7_0_Base_OILC.pdf), the software powering IBM FlashSystem enterprise storage arrays
 - [**Inciga**](https://fossies.org/linux/icinga2/third-party/nlohmann_json/json.hpp), a monitoring tool for IT infrastructure, designed to provide insights into system performance and availability through customizable dashboards and alerts
 - [**Intel Accelerator Management Daemon for VMware ESXi**](https://downloadmirror.intel.com/772507/THIRD-PARTY.txt), a management tool designed for monitoring and controlling Intel hardware accelerators within VMware ESXi environments, optimizing performance and resource allocation
 - [**Juniper Identity Management Service**](https://www.juniper.net/documentation/us/en/software/jims/jims-guide/jims-guide.pdf)
+- [**Meta FBOSS**](https://github.com/facebook/fboss), the software stack that controls the network switches in Meta's data centers
 - [**Microsoft Azure IoT SDK**](https://library.e.abb.com/public/2779c5f85f30484192eb3cb3f666a201/IP%20Gateway%20Open%20License%20Declaration_9AKK108467A4095_Rev_C.pdf), a collection of tools and libraries to help developers connect, build, and deploy Internet of Things (IoT) solutions on the Azure cloud platform
+- [**Microsoft Confidential Consortium Framework**](https://github.com/microsoft/CCF), a framework for building secure, highly available applications on trusted execution environments
 - [**Microsoft WinGet**](https://github.com/microsoft/winget-cli), a command-line utility included in the Windows Package Manager
+- [**Mitsubishi Electric SECS/GEM**](https://dl.mitsubishielectric.com/dl/fa/document/manual/plc/sh082483eng/sh082483engi.pdf), the semiconductor equipment communication software running on Mitsubishi Electric C Controller and C intelligent function modules
+- [**Moxa**](https://www.moxa.com/getmedia/fbe2a0c7-8dda-4b5b-a501-15e45adebb1f/moxa-foss-statement-for-da-720-series-win-10-ltsc-21h2-declaration-v1.0.pdf), a provider of industrial networking, computing, and automation infrastructure
 - [**plexusAV**](https://www.sisme.com/media/10994/manual_plexusav-p-avn-4-form8244-c.pdf), a high-performance AV-over-IP transceiver device capable of video encoding and decoding using the IPMX standard
 - [**Pointr**](https://docs-dev.pointr.tech/docs/8.x/Developer%20Portal/Open%20Source%20Licenses/), a platform for indoor positioning and navigation solutions, offering tools and SDKs for developers to create location-based applications
 - [**secunet protect4use**](https://www.secunet.com/en/about-us/press/article/elstersecure-bietet-komfortablen-login-ohne-passwort-dank-secunet-protect4use), a secure, passwordless multifactor authentication solution that transforms smartphones into digital keyrings, ensuring high security for online services and digital identities
 - [**Sencore MRD 7000**](https://www.foccusdigital.com/wp-content/uploads/2025/03/MRD-7000-Manual-8175V.pdf), a professional multi-channel receiver and decoder supporting UHD and HD stream decoding
+- [**Siemens SINEC**](https://cache.industry.siemens.com/dl/files/917/109974917/att_1298783/v2/OSS_SINEC-NMS_99.pdf), a family of network management and infrastructure services for industrial networks
+- [**Toshiba Industrial Servers**](https://www.global.toshiba/content/dam/toshiba/jp/products-solutions/industrial/computer/product/server/fs20000r/pdf/FS20000R_OSS_License_6E8C5817_rev0.pdf), the FS20000R series of industrial servers for factory automation and control systems
+- [**Wazuh**](https://github.com/wazuh/wazuh/blob/main/src/data_provider/src/sysInfo.cpp), a security platform for threat detection, integrity monitoring and incident response
+- [**ZeroTier**](https://github.com/zerotier/ZeroTierOne/blob/dev/osdep/OSUtils.hpp), a software-defined networking service that creates virtual Ethernet networks
@@ -933,6 +933,34 @@ BSON stores the length of documents, arrays, strings, and binary values in a sig
    [`to_bson`](../api/basic_json/to_bson.md) produced documents with negative length prefixes that
    [`from_bson`](../api/basic_json/from_bson.md) rejected.

+### json.exception.out_of_range.413
+
+A JSON Patch `remove` operation cannot be applied because the target location's parent is neither an object nor an array. Per [RFC 6902](https://datatracker.ietf.org/doc/html/rfc6902), a `remove` target must reference a member of an existing object or an element of an existing array; a primitive value (string, number, boolean, etc.) or `null` has no members or elements to remove.
+
+!!! failure "Example message"
+
+    ```
+    cannot remove value: the JSON Patch 'remove' target's parent is of type number, but must be an object or array
+    ```
+
+!!! note
+
+    This exception was added in version 3.13.0. Before that, this situation was silently ignored (the `remove` operation had no effect).
+
+### json.exception.out_of_range.414
+
+A JSON Patch `move` operation's `"from"` location is a proper prefix of its `"path"` location. Per [RFC 6902](https://datatracker.ietf.org/doc/html/rfc6902) (section 4.4), a location cannot be moved into one of its own children.
+
+!!! failure "Example message"
+
+    ```
+    cannot move value: 'from' path '/0' is a proper prefix of 'path' '/0/0'
+    ```
+
+!!! note
+
+    This exception was added in version 3.13.0. Before that, this situation could succeed with a corrupted result: for an array target, removing the "from" element before the "add" step shifted subsequent indices, so "path" silently re-resolved to a different element than intended.
+
 ## Further exceptions

 This exception is thrown in case of errors that cannot be classified with the
@@ -98,7 +98,6 @@ nav:
      - Types:
          - features/types/index.md
          - features/types/number_handling.md
-          - features/types/template_parameters.md
  - Integration:
      - integration/index.md
      - integration/migration_guide.md
@@ -1,7 +1,7 @@
 wheel==0.48.0

 mkdocs==1.6.1                                       # documentation framework
-mkdocs-git-revision-date-localized-plugin==1.5.3    # plugin "git-revision-date-localized"
+mkdocs-git-revision-date-localized-plugin==1.5.4    # plugin "git-revision-date-localized"
 mkdocs-material==9.7.7                             # theme for mkdocs
 mkdocs-material-extensions==1.3.1                   # extensions
 mkdocs-minify-plugin==0.8.0                         # plugin "minify"
@@ -398,6 +398,17 @@ inline void from_json(const BasicJsonType& j, CompatibleArrayType& bin)
    }
 }

+template<typename ConstructibleObjectType>
+auto from_json_object_reserve(ConstructibleObjectType& obj, typename ConstructibleObjectType::size_type size, priority_tag<1> /*unused*/)
+-> decltype(obj.reserve(size), void())
+{
+    obj.reserve(size);
+}
+
+template<typename ConstructibleObjectType>
+inline void from_json_object_reserve(ConstructibleObjectType& /*obj*/, std::size_t /*size*/, priority_tag<0> /*unused*/)
+{}
+
 template<typename BasicJsonType, typename ConstructibleObjectType,
         enable_if_t<is_constructible_object_type<BasicJsonType, ConstructibleObjectType>::value, int> = 0>
 inline void from_json(const BasicJsonType& j, ConstructibleObjectType& obj)
@@ -409,6 +420,7 @@ inline void from_json(const BasicJsonType& j, ConstructibleObjectType& obj)

    ConstructibleObjectType ret;
    const auto* inner_object = j.template get_ptr<const typename BasicJsonType::object_t*>();
+    from_json_object_reserve(ret, inner_object->size(), priority_tag<1> {});
    for (const auto& p : *inner_object)
    {
        ret.emplace(p.first, p.second.template get<typename ConstructibleObjectType::mapped_type>());
@@ -1075,8 +1075,8 @@ char* to_chars(char* first, const char* last, FloatType value)
    }

 #ifdef __GNUC__
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Wfloat-equal"
+    JSON_HEDLEY_DIAGNOSTIC_PUSH
+    JSON_HEDLEY_PRAGMA(GCC diagnostic ignored "-Wfloat-equal")
 #endif
    if (value == 0) // +-0
    {
@@ -1087,7 +1087,7 @@ char* to_chars(char* first, const char* last, FloatType value)
        return first;
    }
 #ifdef __GNUC__
-#pragma GCC diagnostic pop
+    JSON_HEDLEY_DIAGNOSTIC_POP
 #endif

    JSON_ASSERT(last - first >= std::numeric_limits<FloatType>::max_digits10);
@@ -33,8 +33,8 @@
 // code stumbling over this. See https://github.com/nlohmann/json/issues/4087
 // for a discussion.
 #if defined(__clang__)
-    #pragma clang diagnostic push
-    #pragma clang diagnostic ignored "-Wweak-vtables"
+    JSON_HEDLEY_DIAGNOSTIC_PUSH
+    JSON_HEDLEY_PRAGMA(clang diagnostic ignored "-Wweak-vtables")
 #endif

 NLOHMANN_JSON_NAMESPACE_BEGIN
@@ -101,10 +101,7 @@ class exception : public std::exception
                    {
                        if (&element.second == current)
                        {
-                            // data() is null-terminated, so a key containing
-                            // a null byte is cut short here rather than
-                            // truncating the whole message at what()
-                            tokens.emplace_back(element.first.data());
+                            tokens.emplace_back(element.first.c_str());
                            break;
                        }
                    }
@@ -290,5 +287,5 @@ class other_error : public exception
 NLOHMANN_JSON_NAMESPACE_END

 #if defined(__clang__)
-    #pragma clang diagnostic pop
+    JSON_HEDLEY_DIAGNOSTIC_POP
 #endif
@@ -114,9 +114,7 @@ std::size_t hash(const BasicJsonType& j)
            seed = combine(seed, static_cast<std::size_t>(j.get_binary().subtype()));
            for (const auto byte : j.get_binary())
            {
-                // the cast is needed for binary types whose value type is not
-                // an integer (e.g., std::byte)
-                seed = combine(seed, std::hash<std::uint8_t> {}(static_cast<std::uint8_t>(byte)));
+                seed = combine(seed, std::hash<std::uint8_t> {}(byte));
            }
            return seed;
        }
@@ -2899,10 +2899,7 @@ class binary_reader
                               number_string,
                               out_of_range::create(406, concat("number overflow parsing '", number_string, '\''), nullptr));
                }
-                // number_string is a std::string, while the SAX interface takes a
-                // string_t; convert explicitly, as the two are only implicitly
-                // convertible for some string types
-                return sax->number_float(parsed_float, string_t(number_string.data(), number_string.size()));
+                return sax->number_float(parsed_float, std::move(number_string));
            }
            case token_type::uninitialized:
            case token_type::literal_true:
@@ -149,10 +149,11 @@ class lexer : public lexer_base<BasicJsonType>
  public:
    using token_type = typename lexer_base<BasicJsonType>::token_type;

-    explicit lexer(InputAdapterType&& adapter, bool ignore_comments_ = false) noexcept
+    explicit lexer(InputAdapterType&& adapter, bool ignore_comments_ = false, bool discard_number_values_ = false) noexcept
        : ia(std::move(adapter))
        , ignore_comments(ignore_comments_)
        , decimal_point_char(static_cast<char_int_type>(get_decimal_point()))
+        , discard_number_values(discard_number_values_)
    {}

    // deleted because of pointer members
@@ -1279,6 +1280,58 @@ scan_number_done:
        // we are done scanning a number)
        unget();

+        // If the caller does not need the converted value (only whether the
+        // input is syntactically valid; see json_sax_acceptor/accept()), an
+        // unsigned/integer token can be reported without calling
+        // strtoull()/strtoll() at all, *provided* we can already tell from
+        // the digit count alone that the conversion cannot overflow 64 bits.
+        // Such tokens are always finite and are accepted unconditionally by
+        // the parser regardless of their actual value (parser::sax_parse_internal()
+        // never checks finiteness for value_unsigned/value_integer), so the
+        // classification below is all that is needed.
+        //
+        // A decimal number with up to 18 digits is always representable in
+        // both std::uint64_t and std::int64_t (18 nines is ~1e18, well below
+        // both UINT64_MAX ~1.8e19 and INT64_MAX ~9.2e18), so strtoull()/strtoll()
+        // could not have set errno to ERANGE for it. Numbers with more digits
+        // (rare in practice) fall through to the exact code below, unchanged,
+        // so their handling -- including reclassification to value_float when
+        // the value overflows 64 bits, and rejection when it is not even
+        // finite as a double -- is bit-for-bit identical to before this
+        // optimization.
+        //
+        // Note this reasons about std::uint64_t/std::int64_t, not about
+        // number_unsigned_t/number_integer_t (BasicJsonType's own, possibly
+        // narrower, template parameters -- e.g. std::uint32_t). That is fine
+        // *only* because discard_number_values is exclusively set by
+        // accept() (see json.hpp), and accept() always parses through the
+        // library's own json_sax_acceptor -- never a user-supplied SAX
+        // consumer -- whose number_unsigned()/number_integer()/number_float()
+        // callbacks unconditionally discard their argument and return true.
+        // So for every caller that can reach this branch, neither the token
+        // classification below nor the eventual (possibly narrowed, and on
+        // this fast path left stale/unset) value_unsigned/value_integer is
+        // ever consulted -- an unsigned/integer token is accepted outright,
+        // and even a >18-digit token that this fast path deliberately falls
+        // through for is, once reclassified to value_float, still finite
+        // (and thus accepted) for any digit count that fits in number_unsigned_t
+        // or number_integer_t regardless of that type's width. If this
+        // function is ever taught to run with discard_number_values true for
+        // a caller that *does* read the converted value, this reasoning (and
+        // the fast path below) would need to be revisited.
+        if (discard_number_values)
+        {
+            constexpr std::size_t safe_digit_count = 18;
+            if (number_type == token_type::value_unsigned && token_buffer.size() <= safe_digit_count)
+            {
+                return token_type::value_unsigned;
+            }
+            if (number_type == token_type::value_integer && token_buffer.size() - 1 <= safe_digit_count)
+            {
+                return token_type::value_integer;
+            }
+        }
+
        char* endptr = nullptr; // NOLINT(misc-const-correctness,cppcoreguidelines-pro-type-vararg,hicpp-vararg)
        errno = 0;

@@ -1393,8 +1446,7 @@ scan_number_done:
    */
    char_int_type get()
    {
-        ++position.chars_read_total;
-        ++position.chars_read_current_line;
+        advance_position();

        if (next_unget)
        {
@@ -1406,6 +1458,23 @@ scan_number_done:
            current = ia.get_character();
        }

+        return track_after_read();
+    }
+
+    /// shared head of get() / get_ignoring_pending_unget(): bump the
+    /// per-character position counters (line-count-on-'\n' bookkeeping is
+    /// handled afterwards, in track_after_read(), once `current` is known)
+    void advance_position() noexcept
+    {
+        ++position.chars_read_total;
+        ++position.chars_read_current_line;
+    }
+
+    /// shared tail of get() / get_ignoring_pending_unget(): capture the
+    /// character for error messages (if needed) and update line/column
+    /// bookkeeping for the character now in `current`
+    char_int_type track_after_read()
+    {
        // seekable adapters reconstruct the token lazily on error (see
        // get_token_string), so the eager per-character copy is skipped
        capture_char(std::integral_constant<bool, lazy_token_string> {});
@@ -1419,6 +1488,29 @@ scan_number_done:
        return current;
    }

+    /*!
+    @brief like get(), but for call sites that can prove no unget() is pending
+
+    get() has to check the `next_unget` flag on every call, because a
+    previous token may have ended with unget() (e.g. scan_number() always
+    ungets the character that terminated the number, so the next call to
+    scan() can see it again). skip_whitespace() reads that first,
+    possibly-ungotten character via a plain get(), but every further
+    character it reads is guaranteed to be a fresh read: nothing between
+    those calls invokes unget(). This variant skips the (otherwise always
+    false) next_unget branch for those calls; it is not a general
+    replacement for get().
+    */
+    char_int_type get_ignoring_pending_unget()
+    {
+        JSON_ASSERT(!next_unget);
+
+        advance_position();
+        current = ia.get_character();
+
+        return track_after_read();
+    }
+
    /// seekable adapter: nothing to capture, the token is rebuilt on error
    void capture_char(std::true_type /*lazy*/) const noexcept {}

@@ -1612,13 +1704,37 @@ scan_number_done:
        return true;
    }

+    /// whether `current` is one of the four JSON whitespace characters
+    bool current_is_whitespace() const noexcept
+    {
+        return current == ' ' || current == '\t' || current == '\n' || current == '\r';
+    }
+
    void skip_whitespace()
    {
+        // the first character may be a pending unget() left over from the
+        // previous token (see get_ignoring_pending_unget()); every
+        // subsequent character read by this loop is guaranteed fresh, since
+        // nothing below calls unget()
+        get();
+
+        if (!current_is_whitespace())
+        {
+            return;
+        }
+
+        // this is written as an if-guarded do-while (rather than a plain
+        // while loop) because that shape is what lets both GCC and Clang
+        // keep the input adapter's read pointer in a register across
+        // iterations; the equivalent while-loop measurably defeated that
+        // optimization in testing, turning long whitespace runs (e.g. the
+        // indentation of pretty-printed JSON) from a register-only loop
+        // into one that reloads the pointer from memory every character
        do
        {
-            get();
+            get_ignoring_pending_unget();
        }
-        while (current == ' ' || current == '\t' || current == '\n' || current == '\r');
+        while (current_is_whitespace());
    }

    token_type scan()
@@ -1754,6 +1870,13 @@ scan_number_done:
    const char_int_type decimal_point_char = '.';
    /// the position of the decimal point in the input
    std::size_t decimal_point_position = std::string::npos;
+
+    /// whether the caller (e.g. accept()/json_sax_acceptor) only needs the
+    /// token classification and never looks at the converted numeric value;
+    /// when set, scan_number() may skip strtoull()/strtoll() for
+    /// value_unsigned/value_integer tokens whose digit count guarantees they
+    /// fit into 64 bits (see scan_number())
+    const bool discard_number_values = false;
 };

 }  // namespace detail
@@ -72,9 +72,10 @@ class parser
                    parser_callback_t<BasicJsonType> cb = nullptr,
                    const bool allow_exceptions_ = true,
                    const bool ignore_comments = false,
-                    const bool ignore_trailing_commas_ = false)
+                    const bool ignore_trailing_commas_ = false,
+                    const bool discard_number_values_ = false)
        : callback(std::move(cb))
-        , m_lexer(std::move(adapter), ignore_comments)
+        , m_lexer(std::move(adapter), ignore_comments, discard_number_values_)
        , allow_exceptions(allow_exceptions_)
        , ignore_trailing_commas(ignore_trailing_commas_)
    {
@@ -88,13 +88,8 @@ class iter_impl // NOLINT(cppcoreguidelines-special-member-functions,hicpp-speci

    iter_impl() = default;
    ~iter_impl() = default;
-    // the exception specification is left to be computed rather than declared:
-    // an array or object type whose iterator is not nothrow move constructible
-    // (std::deque's is not before libstdc++ 11) would make a declared noexcept
-    // differ from the implicit one, which deletes the function -- and is an
-    // error outright with older compilers
-    iter_impl(iter_impl&&) = default; // NOLINT(hicpp-noexcept-move,performance-noexcept-move-constructor,cppcoreguidelines-noexcept-move-operations)
-    iter_impl& operator=(iter_impl&&) = default; // NOLINT(hicpp-noexcept-move,performance-noexcept-move-constructor,cppcoreguidelines-noexcept-move-operations)
+    iter_impl(iter_impl&&) noexcept = default;
+    iter_impl& operator=(iter_impl&&) noexcept = default;

    /*!
    @brief constructor for a given JSON instance
@@ -18,6 +18,7 @@
 #endif

 #include <nlohmann/detail/abi_macros.hpp>
+#include <nlohmann/detail/macro_scope.hpp>
 #include <nlohmann/detail/meta/type_traits.hpp>
 #include <nlohmann/detail/string_utils.hpp>
 #include <nlohmann/detail/value_t.hpp>
@@ -206,10 +207,10 @@ NLOHMANN_JSON_NAMESPACE_END
 namespace std
 {

+// Fix: https://github.com/nlohmann/json/issues/1401
 #if defined(__clang__)
-    // Fix: https://github.com/nlohmann/json/issues/1401
-    #pragma clang diagnostic push
-    #pragma clang diagnostic ignored "-Wmismatched-tags"
+    JSON_HEDLEY_DIAGNOSTIC_PUSH
+    JSON_HEDLEY_PRAGMA(clang diagnostic ignored "-Wmismatched-tags")
 #endif
 template<typename IteratorType>
 class tuple_size<::nlohmann::detail::iteration_proxy_value<IteratorType>> // NOLINT(cert-dcl58-cpp)
@@ -224,7 +225,7 @@ class tuple_element<N, ::nlohmann::detail::iteration_proxy_value<IteratorType >>
                            ::nlohmann::detail::iteration_proxy_value<IteratorType >> ()));
 };
 #if defined(__clang__)
-    #pragma clang diagnostic pop
+    JSON_HEDLEY_DIAGNOSTIC_POP
 #endif

 }  // namespace std
@@ -17,7 +17,6 @@
 #endif  // JSON_NO_IO
 #include <limits> // max
 #include <numeric> // accumulate
-#include <set> // set
 #include <string> // string
 #include <utility> // move
 #include <vector> // vector
@@ -72,7 +71,7 @@ class json_pointer
                               string_t{},
                               [](const string_t& a, const string_t& b)
        {
-            return detail::concat<string_t>(a, '/', detail::escape(b));
+            return detail::concat(a, '/', detail::escape(b));
        });
    }

@@ -266,7 +265,7 @@ class json_pointer
            JSON_THROW(detail::parse_error::create(109, 0, detail::concat("array index '", s, "' is not a number"), nullptr));
        }

-        const char* p = s.data();
+        const char* p = s.c_str();
        char* p_end = nullptr; // NOLINT(misc-const-correctness)
        errno = 0; // strtoull doesn't reset errno
        const unsigned long long res = std::strtoull(p, &p_end, 10); // NOLINT(runtime/int)
@@ -301,35 +300,19 @@ class json_pointer
    }

  private:
-    /*!
-    @brief the reference token sequences that denote arrays
-
-    @ref unflatten collects the pointer prefixes that have a reference token 0
-    among their children; @ref get_and_create creates arrays exactly below
-    those prefixes and objects everywhere else. Deciding this up front keeps
-    the result independent of the order in which the flattened object is
-    iterated, which is unspecified for some object types.
-    */
-    using array_parents_t = std::set<std::vector<string_t>>;
-
    /*!
    @brief create and return a reference to the pointed to value

    @complexity Linear in the number of reference tokens.

-    @throw parse_error.106 if an array index begins with '0'
    @throw parse_error.109 if array index is not a number
    @throw type_error.313 if value cannot be unflattened
    */
    template<typename BasicJsonType>
-    BasicJsonType& get_and_create(BasicJsonType& j, const array_parents_t& array_parents) const
+    BasicJsonType& get_and_create(BasicJsonType& j) const
    {
        auto* result = &j;

-        // the reference tokens that have been consumed so far; used to look up
-        // whether the value to be created below is an array or an object
-        std::vector<string_t> prefix;
-
        // in case no reference tokens exist, return a reference to the JSON value
        // j which will be overwritten by a primitive value
        for (const auto& reference_token : reference_tokens)
@@ -338,11 +321,10 @@ class json_pointer
            {
                case detail::value_t::null:
                {
-                    if (array_parents.find(prefix) != array_parents.end())
+                    if (reference_token == "0")
                    {
-                        // some reference token below this position is 0, so the
-                        // value is an array
-                        result = &result->operator[](array_index<BasicJsonType>(reference_token));
+                        // start a new array if the reference token is 0
+                        result = &result->operator[](0);
                    }
                    else
                    {
@@ -382,8 +364,6 @@ class json_pointer
                default:
                    JSON_THROW(detail::type_error::create(313, "invalid value to unflatten", &j));
            }
-
-            prefix.push_back(reference_token);
        }

        return *result;
@@ -768,6 +748,20 @@ class json_pointer
                        }
                    }

+                    // the reference token consists only of digits at this point (cf. checks
+                    // above); however, its numeric value might not be representable, in which
+                    // case array_index() would throw out_of_range.404/410 -- contains() must
+                    // not throw (see #5395), so such a reference token is treated as "not found"
+                    errno = 0; // strtoull() does not reset errno on success
+                    char* p_end = nullptr; // NOLINT(misc-const-correctness)
+                    const unsigned long long magnitude = std::strtoull(reference_token.c_str(), &p_end, 10); // NOLINT(runtime/int)
+                    if (JSON_HEDLEY_UNLIKELY(errno == ERANGE // the value exceeds ULLONG_MAX
+                                             || magnitude >= static_cast<unsigned long long>((std::numeric_limits<typename BasicJsonType::size_type>::max)()))) // NOLINT(runtime/int)
+                    {
+                        // the array index cannot be represented as size_type
+                        return false;
+                    }
+
                    const auto idx = array_index<BasicJsonType>(reference_token);
                    if (idx >= ptr->size())
                    {
@@ -843,8 +837,7 @@ class json_pointer
        {
            // use the text between the beginning of the reference token
            // (start) and the last slash (slash).
-            const auto count = (slash == string_t::npos ? reference_string.size() : slash) - start;
-            auto reference_token = string_t(reference_string.data() + start, count);
+            auto reference_token = reference_string.substr(start, slash - start);

            // check reference tokens are properly escaped
            for (std::size_t pos = reference_token.find_first_of('~');
@@ -960,24 +953,6 @@ class json_pointer

        BasicJsonType result;

-        // collect the pointer prefixes that have a reference token 0 among
-        // their children; the values below them are arrays, all others are
-        // objects (see array_parents_t)
-        array_parents_t array_parents;
-        for (const auto& element : *value.m_data.m_value.object)
-        {
-            json_pointer ptr(element.first);
-            std::vector<string_t> prefix;
-            for (auto& reference_token : ptr.reference_tokens)
-            {
-                if (reference_token == "0")
-                {
-                    array_parents.insert(prefix);
-                }
-                prefix.push_back(std::move(reference_token));
-            }
-        }
-
        // iterate the JSON object values
        for (const auto& element : *value.m_data.m_value.object)
        {
@@ -990,7 +965,7 @@ class json_pointer
            // that if the JSON pointer is "" (i.e., points to the whole value),
            // function get_and_create returns a reference to the result itself.
            // An assignment will then create a primitive value.
-            json_pointer(element.first).get_and_create(result, array_parents) = element.second;
+            json_pointer(element.first).get_and_create(result) = element.second;
        }

        return result;
@@ -172,18 +172,17 @@ struct has_to_json < BasicJsonType, T, enable_if_t < !is_basic_json<T>::value >>
 template<typename T>
 using detect_key_compare = typename T::key_compare;

-// obtains the actual object key comparator: object_t::key_compare if the
-// object type defines it, and default_object_comparator_t otherwise
-//
-// note detected_or_t is used rather than std::conditional, because the latter
-// names both of its type arguments eagerly; object_t::key_compare would then
-// be a hard error for an object type that does not define it
+template<typename T>
+struct has_key_compare : std::integral_constant<bool, is_detected<detect_key_compare, T>::value> {};
+
+// obtains the actual object key comparator
 template<typename BasicJsonType>
 struct actual_object_comparator
 {
    using object_t = typename BasicJsonType::object_t;
    using object_comparator_t = typename BasicJsonType::default_object_comparator_t;
-    using type = detected_or_t<object_comparator_t, detect_key_compare, object_t>;
+    using type = typename std::conditional < has_key_compare<object_t>::value,
+          typename object_t::key_compare, object_comparator_t>::type;
 };

 template<typename BasicJsonType>
@@ -779,22 +778,6 @@ using has_erase_with_key_type = typename std::conditional <
                                std::true_type,
                                std::false_type >::type;

-template<typename ObjectType, typename IteratorType>
-using detect_erase_with_iterator = decltype(std::declval<ObjectType&>().erase(std::declval<IteratorType>()));
-
-// type trait to check if erase(iterator) returns void instead of the following
-// iterator, as the object types that do not compute a successor the caller may
-// not need do
-template<typename ObjectType, typename IteratorType>
-using erase_returns_void = is_detected_exact<void, detect_erase_with_iterator, ObjectType, IteratorType>;
-
-template<typename T>
-using detect_capacity = decltype(std::declval<const T&>().capacity());
-
-// type trait to check if a type has a capacity() member function
-template<typename T>
-struct has_capacity : std::integral_constant<bool, is_detected<detect_capacity, T>::value> {};
-
 // a naive helper to check if a type is an ordered_map (exploits the fact that
 // ordered_map inherits capacity() from std::vector)
 template <typename T>
@@ -261,7 +261,7 @@ class binary_writer

                // step 2: write the string
                oa->write_characters(
-                    reinterpret_cast<const CharType*>(j.m_data.m_value.string->data()),
+                    reinterpret_cast<const CharType*>(j.m_data.m_value.string->c_str()),
                    j.m_data.m_value.string->size());
                break;
            }
@@ -581,7 +581,7 @@ class binary_writer

                // step 2: write the string
                oa->write_characters(
-                    reinterpret_cast<const CharType*>(j.m_data.m_value.string->data()),
+                    reinterpret_cast<const CharType*>(j.m_data.m_value.string->c_str()),
                    j.m_data.m_value.string->size());
                break;
            }
@@ -798,7 +798,7 @@ class binary_writer
                }
                write_number_with_ubjson_prefix(j.m_data.m_value.string->size(), true, use_bjdata);
                oa->write_characters(
-                    reinterpret_cast<const CharType*>(j.m_data.m_value.string->data()),
+                    reinterpret_cast<const CharType*>(j.m_data.m_value.string->c_str()),
                    j.m_data.m_value.string->size());
                break;
            }
@@ -887,9 +887,7 @@ class binary_writer
                    for (size_t i = 0; i < j.m_data.m_value.binary->size(); ++i)
                    {
                        oa->write_character(to_char_type(bjdata_draft3 ? 'B' : 'U'));
-                        // the cast is needed for binary types whose value type
-                        // is not an integer (e.g., std::byte)
-                        oa->write_character(to_char_type(static_cast<std::uint8_t>(j.m_data.m_value.binary->data()[i])));
+                        oa->write_character(to_char_type(j.m_data.m_value.binary->data()[i]));
                    }
                }

@@ -950,7 +948,7 @@ class binary_writer
                {
                    write_number_with_ubjson_prefix(el.first.size(), true, use_bjdata);
                    oa->write_characters(
-                        reinterpret_cast<const CharType*>(el.first.data()),
+                        reinterpret_cast<const CharType*>(el.first.c_str()),
                        el.first.size());
                    write_ubjson(el.second, use_count, use_type, prefix_required, use_bjdata, bjdata_version);
                }
@@ -1013,11 +1011,8 @@ class binary_writer
    {
        oa->write_character(to_char_type(element_type));
        oa->write_characters(
-            reinterpret_cast<const CharType*>(name.data()),
-            name.size());
-        // the terminating null byte is written explicitly rather than taken
-        // from the buffer, so that string_t::data() need not be null-terminated
-        oa->write_character(to_char_type(0x00));
+            reinterpret_cast<const CharType*>(name.c_str()),
+            name.size() + 1u);
    }

    /*!
@@ -1058,11 +1053,8 @@ class binary_writer

        write_number<std::int32_t>(to_bson_length(value.size() + 1ul), true);
        oa->write_characters(
-            reinterpret_cast<const CharType*>(value.data()),
-            value.size());
-        // the terminating null byte is written explicitly rather than taken
-        // from the buffer, so that string_t::data() need not be null-terminated
-        oa->write_character(to_char_type(0x00));
+            reinterpret_cast<const CharType*>(value.c_str()),
+            value.size() + 1);
    }

    /*!
@@ -1153,11 +1145,7 @@ class binary_writer

        const std::size_t embedded_document_size = std::accumulate(std::begin(value), std::end(value), static_cast<std::size_t>(0), [&array_index](std::size_t result, const typename BasicJsonType::array_t::value_type & el)
        {
-            // the index is built as a std::string, while calc_bson_element_size
-            // takes a string_t; convert explicitly, as the two are only
-            // implicitly convertible for some string types
-            const auto key = std::to_string(array_index++);
-            return result + calc_bson_element_size(string_t(key.data(), key.size()), el);
+            return result + calc_bson_element_size(std::to_string(array_index++), el);
        });

        return sizeof(std::int32_t) + embedded_document_size + 1ul;
@@ -1184,11 +1172,7 @@ class binary_writer

        for (const auto& el : value)
        {
-            // the index is built as a std::string, while write_bson_element takes
-            // a string_t; convert explicitly, as the two are only implicitly
-            // convertible for some string types
-            const auto key = std::to_string(array_index++);
-            write_bson_element(string_t(key.data(), key.size()), el);
+            write_bson_element(std::to_string(array_index++), el);
        }

        oa->write_character(to_char_type(0x00));
@@ -1663,6 +1647,20 @@ class binary_writer
        return 'D';  // float 64
    }

+    /*!
+    @brief checks whether a JSON number fits into @a TargetType
+    @param[in] el a JSON number of either the signed or unsigned integer kind
+    @return whether @a el's value can be represented by @a TargetType without
+            wrapping, regardless of which of the two kinds it is stored as
+    */
+    template<typename TargetType>
+    static bool bjdata_ndarray_value_in_range(const BasicJsonType& el)
+    {
+        return el.is_number_unsigned()
+               ? value_in_range_of<TargetType>(el.template get<std::uint64_t>())
+               : value_in_range_of<TargetType>(el.template get<std::int64_t>());
+    }
+
    /*!
    @return false if the object is successfully converted to a bjdata ndarray, true if the type or size is invalid
    */
@@ -1674,6 +1672,16 @@ class binary_writer
        };

        string_t key = "_ArrayType_";
+        // the type name is looked up as a string below; a non-string
+        // annotation (e.g. a number, null, or an array) cannot name a known
+        // dtype, so it is treated the same as an unrecognized type name and
+        // falls back to a plain object encoding instead of throwing
+        // type_error.302 out of get<string_t>()
+        if (!value.at(key).is_string())
+        {
+            return true;
+        }
+
        // use get<string_t>() instead of static_cast<string_t> to avoid an
        // ambiguous conversion under explicit instantiation on C++17 (see #4825)
        auto it = bjdtype.find(value.at(key).template get<string_t>());
@@ -1683,7 +1691,26 @@ class binary_writer
        }
        CharType dtype = it->second;

+        // the 'B' (byte) marker is only defined by BJData Draft 3; emitting it
+        // under the default Draft 2 mode would produce a stream that Draft 2
+        // readers reject, so such an object falls back to a plain object
+        // encoding instead (see the "Binary values" section of the BJData
+        // documentation)
+        if (dtype == 'B' && bjdata_version != bjdata_version_t::draft3)
+        {
+            return true;
+        }
+
        key = "_ArraySize_";
+        // the dimensions are written verbatim as the header length below, so a
+        // value that is not an array cannot produce a valid one: null emits 'Z'
+        // and an object emits '{', neither of which a reader accepts after '#'.
+        // Such an object is not a valid ndarray and falls back to a plain object.
+        if (!value.at(key).is_array())
+        {
+            return true;
+        }
+
        std::size_t len = (value.at(key).empty() ? 0 : 1);
        for (const auto& el : value.at(key))
        {
@@ -1738,6 +1765,60 @@ class binary_writer
            }
        }

+        // every element is cast to the (possibly narrower) C++ type matching
+        // dtype below; a value that does not fit that type would silently
+        // wrap (integers) or overflow to infinity (the "single" precision
+        // float) instead of being reported, so such an object falls back to
+        // a plain object encoding as well
+        for (const auto& el : value.at(key))
+        {
+            bool in_range = true;
+            switch (dtype)
+            {
+                case 'U':
+                case 'C':
+                case 'B':
+                    in_range = bjdata_ndarray_value_in_range<std::uint8_t>(el);
+                    break;
+                case 'i':
+                    in_range = bjdata_ndarray_value_in_range<std::int8_t>(el);
+                    break;
+                case 'u':
+                    in_range = bjdata_ndarray_value_in_range<std::uint16_t>(el);
+                    break;
+                case 'I':
+                    in_range = bjdata_ndarray_value_in_range<std::int16_t>(el);
+                    break;
+                case 'm':
+                    in_range = bjdata_ndarray_value_in_range<std::uint32_t>(el);
+                    break;
+                case 'l':
+                    in_range = bjdata_ndarray_value_in_range<std::int32_t>(el);
+                    break;
+                case 'M':
+                    in_range = bjdata_ndarray_value_in_range<std::uint64_t>(el);
+                    break;
+                case 'L':
+                    in_range = bjdata_ndarray_value_in_range<std::int64_t>(el);
+                    break;
+                case 'd':
+                {
+                    const auto dval = el.template get<double>();
+                    in_range = !std::isfinite(dval) ||
+                               (dval >= static_cast<double>(std::numeric_limits<float>::lowest()) &&
+                                dval <= static_cast<double>((std::numeric_limits<float>::max)()));
+                    break;
+                }
+                default:
+                    // 'D' (double) already spans the full range of number_float_t
+                    break;
+            }
+            if (!in_range)
+            {
+                return true;
+            }
+        }
+
        oa->write_character('[');
        oa->write_character('$');
        oa->write_character(dtype);
@@ -1857,8 +1938,8 @@ class binary_writer
    void write_compact_float(const number_float_t n, detail::input_format_t format)
    {
 #ifdef __GNUC__
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Wfloat-equal"
+        JSON_HEDLEY_DIAGNOSTIC_PUSH
+        JSON_HEDLEY_PRAGMA(GCC diagnostic ignored "-Wfloat-equal")
 #endif
        if (!std::isfinite(n) || ((static_cast<double>(n) >= static_cast<double>(std::numeric_limits<float>::lowest()) &&
                                   static_cast<double>(n) <= static_cast<double>((std::numeric_limits<float>::max)()) &&
@@ -1877,7 +1958,7 @@ class binary_writer
            write_number(n);
        }
 #ifdef __GNUC__
-#pragma GCC diagnostic pop
+        JSON_HEDLEY_DIAGNOSTIC_POP
 #endif
    }

@@ -135,7 +135,7 @@ class serializer
                    auto i = val.m_data.m_value.object->cbegin();
                    for (std::size_t cnt = 0; cnt < val.m_data.m_value.object->size() - 1; ++cnt, ++i)
                    {
-                        o->write_characters(indent_string.data(), new_indent);
+                        o->write_characters(indent_string.c_str(), new_indent);
                        o->write_character('\"');
                        dump_escaped(i->first, ensure_ascii);
                        o->write_characters("\": ", 3);
@@ -146,14 +146,14 @@ class serializer
                    // last element
                    JSON_ASSERT(i != val.m_data.m_value.object->cend());
                    JSON_ASSERT(std::next(i) == val.m_data.m_value.object->cend());
-                    o->write_characters(indent_string.data(), new_indent);
+                    o->write_characters(indent_string.c_str(), new_indent);
                    o->write_character('\"');
                    dump_escaped(i->first, ensure_ascii);
                    o->write_characters("\": ", 3);
                    dump(i->second, true, ensure_ascii, indent_step, new_indent);

                    o->write_character('\n');
-                    o->write_characters(indent_string.data(), current_indent);
+                    o->write_characters(indent_string.c_str(), current_indent);
                    o->write_character('}');
                }
                else
@@ -208,18 +208,18 @@ class serializer
                    for (auto i = val.m_data.m_value.array->cbegin();
                            i != val.m_data.m_value.array->cend() - 1; ++i)
                    {
-                        o->write_characters(indent_string.data(), new_indent);
+                        o->write_characters(indent_string.c_str(), new_indent);
                        dump(*i, true, ensure_ascii, indent_step, new_indent);
                        o->write_characters(",\n", 2);
                    }

                    // last element
                    JSON_ASSERT(!val.m_data.m_value.array->empty());
-                    o->write_characters(indent_string.data(), new_indent);
+                    o->write_characters(indent_string.c_str(), new_indent);
                    dump(val.m_data.m_value.array->back(), true, ensure_ascii, indent_step, new_indent);

                    o->write_character('\n');
-                    o->write_characters(indent_string.data(), current_indent);
+                    o->write_characters(indent_string.c_str(), current_indent);
                    o->write_character(']');
                }
                else
@@ -265,7 +265,7 @@ class serializer
                        indent_string.resize(indent_string.size() * 2, ' ');
                    }

-                    o->write_characters(indent_string.data(), new_indent);
+                    o->write_characters(indent_string.c_str(), new_indent);

                    o->write_characters("\"bytes\": [", 10);

@@ -274,14 +274,14 @@ class serializer
                        for (auto i = val.m_data.m_value.binary->cbegin();
                                i != val.m_data.m_value.binary->cend() - 1; ++i)
                        {
-                            dump_integer(to_byte_value(*i));
+                            dump_integer(*i);
                            o->write_characters(", ", 2);
                        }
-                        dump_integer(to_byte_value(val.m_data.m_value.binary->back()));
+                        dump_integer(val.m_data.m_value.binary->back());
                    }

                    o->write_characters("],\n", 3);
-                    o->write_characters(indent_string.data(), new_indent);
+                    o->write_characters(indent_string.c_str(), new_indent);

                    o->write_characters("\"subtype\": ", 11);
                    if (val.m_data.m_value.binary->has_subtype())
@@ -293,7 +293,7 @@ class serializer
                        o->write_characters("null", 4);
                    }
                    o->write_character('\n');
-                    o->write_characters(indent_string.data(), current_indent);
+                    o->write_characters(indent_string.c_str(), current_indent);
                    o->write_character('}');
                }
                else
@@ -305,10 +305,10 @@ class serializer
                        for (auto i = val.m_data.m_value.binary->cbegin();
                                i != val.m_data.m_value.binary->cend() - 1; ++i)
                        {
-                            dump_integer(to_byte_value(*i));
+                            dump_integer(*i);
                            o->write_character(',');
                        }
-                        dump_integer(to_byte_value(val.m_data.m_value.binary->back()));
+                        dump_integer(val.m_data.m_value.binary->back());
                    }

                    o->write_characters("],\"subtype\":", 12);
@@ -596,7 +596,7 @@ class serializer
            {
                case error_handler_t::strict:
                {
-                    JSON_THROW(type_error::create(316, concat("incomplete UTF-8 string; last byte: 0x", hex_bytes(static_cast<std::uint8_t>(s[s.size() - 1] | 0))), nullptr));
+                    JSON_THROW(type_error::create(316, concat("incomplete UTF-8 string; last byte: 0x", hex_bytes(static_cast<std::uint8_t>(s.back() | 0))), nullptr));
                }

                case error_handler_t::ignore:
@@ -703,19 +703,6 @@ class serializer
        pos += 6;
    }

-    /*!
-    @brief convert a single element of a binary value to its byte value
-
-    The elements of a binary value are dumped as the numbers 0..255, regardless
-    of the value type of the configured BinaryType: that type may be signed
-    (`char`), unsigned (`std::uint8_t`), or not an integer at all
-    (`std::byte`), none of which @ref dump_integer can handle uniformly.
-    */
-    static std::uint8_t to_byte_value(binary_char_t x) noexcept
-    {
-        return static_cast<std::uint8_t>(x);
-    }
-
    // templates to avoid warnings about useless casts
    template <typename NumberType, enable_if_t<std::is_signed<NumberType>::value, int> = 0>
    bool is_negative_number(NumberType x)
@@ -741,7 +728,8 @@ class serializer
    template < typename NumberType, detail::enable_if_t <
                   std::is_integral<NumberType>::value ||
                   std::is_same<NumberType, number_unsigned_t>::value ||
-                   std::is_same<NumberType, number_integer_t>::value,
+                   std::is_same<NumberType, number_integer_t>::value ||
+                   std::is_same<NumberType, binary_char_t>::value,
                   int > = 0 >
    void dump_integer(NumberType x)
    {
@@ -8,56 +8,50 @@

 #pragma once

-#include <cstddef> // size_t
-
 #include <nlohmann/detail/abi_macros.hpp>

 NLOHMANN_JSON_NAMESPACE_BEGIN
 namespace detail
 {

+/*!
+@brief replace all occurrences of a substring by another string
+
+@param[in,out] s  the string to manipulate; changed so that all
+               occurrences of @a f are replaced with @a t
+@param[in]     f  the substring to replace with @a t
+@param[in]     t  the string to replace @a f
+
+@pre The search string @a f must not be empty. **This precondition is
+enforced with an assertion.**
+
+@since version 2.0.0
+*/
+template<typename StringType>
+inline void replace_substring(StringType& s, const StringType& f,
+                              const StringType& t)
+{
+    JSON_ASSERT(!f.empty());
+    for (auto pos = s.find(f);                // find the first occurrence of f
+            pos != StringType::npos;          // make sure f was found
+            s.replace(pos, f.size(), t),      // replace with t, and
+            pos = s.find(f, pos + t.size()))  // find the next occurrence of f
+    {}
+}
+
 /*!
 * @brief string escaping as described in RFC 6901 (Sect. 4)
 * @param[in] s string to escape
 * @return    escaped string
 *
 * Note the order of escaping "~" to "~0" and "/" to "~1" is important.
- *
- * The string is rebuilt in a single pass, appending whole runs between the
- * characters that need escaping. Scanning with find_first_of() keeps the
- * common case -- nothing to escape -- as fast as a single search, while
- * repeated replace() calls would move the tail of the string once per
- * escaped character.
 */
 template<typename StringType>
-inline StringType escape(const StringType& s)
+inline StringType escape(StringType s)
 {
-    auto next_special = [&s](std::size_t from)
-    {
-        const auto tilde = s.find_first_of('~', from);
-        const auto slash = s.find_first_of('/', from);
-        return tilde < slash ? tilde : slash; // npos is the largest value
-    };
-
-    auto pos = next_special(0);
-    if (pos == StringType::npos)
-    {
-        return s;
-    }
-
-    StringType result;
-    result.reserve(s.size() + 2);
-
-    std::size_t run = 0;
-    while (pos != StringType::npos)
-    {
-        result.append(s.data() + run, pos - run);
-        result.append(s[pos] == '~' ? "~0" : "~1", 2);
-        run = pos + 1;
-        pos = next_special(run);
-    }
-    result.append(s.data() + run, s.size() - run);
-    return result;
+    replace_substring(s, StringType{"~"}, StringType{"~0"});
+    replace_substring(s, StringType{"/"}, StringType{"~1"});
+    return s;
 }

 /*!
@@ -66,43 +60,12 @@ inline StringType escape(const StringType& s)
 * @return    unescaped string
 *
 * Note the order of escaping "~1" to "/" and "~0" to "~" is important.
- *
- * Rebuilt in a single pass, see @ref escape. A "~" that is followed by
- * neither "0" nor "1" is passed through unchanged; @ref json_pointer rejects
- * such input before it gets here.
 */
 template<typename StringType>
 inline void unescape(StringType& s)
 {
-    auto pos = s.find_first_of('~', 0);
-    if (pos == StringType::npos)
-    {
-        return;
-    }
-
-    StringType result;
-    result.reserve(s.size());
-
-    std::size_t run = 0;
-    while (pos != StringType::npos)
-    {
-        result.append(s.data() + run, pos - run);
-
-        const auto next = pos + 1;
-        if (next < s.size() && (s[next] == '0' || s[next] == '1'))
-        {
-            result.append(s[next] == '0' ? "~" : "/", 1);
-            run = pos + 2;
-        }
-        else
-        {
-            result.append("~", 1);
-            run = pos + 1;
-        }
-        pos = s.find_first_of('~', run);
-    }
-    result.append(s.data() + run, s.size() - run);
-    s = result;
+    replace_substring(s, StringType{"~1"}, StringType{"/"});
+    replace_substring(s, StringType{"~0"}, StringType{"~"});
 }

 }  // namespace detail
@@ -9,9 +9,12 @@
 #pragma once

 #include <array> // array
+#include <cmath> // isnan, ldexp, trunc
 #include <cstddef> // size_t
 #include <cstdint> // uint8_t
+#include <limits> // numeric_limits
 #include <string> // string
+#include <type_traits> // is_signed

 #include <nlohmann/detail/macro_scope.hpp>
 #if JSON_HAS_THREE_WAY_COMPARISON
@@ -114,5 +117,67 @@ inline bool operator<(const value_t lhs, const value_t rhs) noexcept
 }
 #endif

+
+/*!
+@brief compare an integer with a floating point number without precision loss
+
+Widening the integer to the floating point type loses precision beyond the
+float's mantissa, which makes equality intransitive: both 2^63-2 and 2^63-1
+round to 2^63, so each compares equal to that float while differing from each
+other. Ordering built on that is not a strict weak ordering, so sorting such
+values, or using them as keys in an ordered container, is undefined behavior.
+
+Returns a value to be compared against zero with the original operator, which
+reproduces the exact ordering. A NaN operand is returned as is, so comparing it
+against zero keeps NaN's semantics: false for the relational operators and
+unordered for `<=>`.
+*/
+template<typename IntegerType, typename FloatType>
+FloatType compare_integer_with_float(const IntegerType i, const FloatType f) noexcept
+{
+    const auto ordered = [](int c) noexcept
+    {
+        return static_cast<FloatType>(c);
+    };
+
+    if (std::isnan(f))
+    {
+        return f;
+    }
+
+    // values of IntegerType lie in [-bound, bound) when signed and in
+    // [0, bound) when unsigned; digits excludes the sign bit, so bound is a
+    // power of two that the float represents exactly
+    const FloatType bound = std::ldexp(static_cast<FloatType>(1), std::numeric_limits<IntegerType>::digits);
+    if (f >= bound)
+    {
+        return ordered(-1);
+    }
+    if (std::is_signed<IntegerType>::value ? (f < -bound) : (f < static_cast<FloatType>(0)))
+    {
+        return ordered(1);
+    }
+
+    // f is now within the integer's range, so truncating it is exact
+    const FloatType truncated = std::trunc(f);
+    const auto as_integer = static_cast<IntegerType>(truncated);
+    if (i != as_integer)
+    {
+        return ordered(i < as_integer ? -1 : 1);
+    }
+
+    // the integer parts agree, so any fractional part decides
+    const FloatType fraction = f - truncated;
+    if (fraction > static_cast<FloatType>(0))
+    {
+        return ordered(-1);
+    }
+    if (fraction < static_cast<FloatType>(0))
+    {
+        return ordered(1);
+    }
+    return ordered(0);
+}
+
 }  // namespace detail
 NLOHMANN_JSON_NAMESPACE_END
@@ -164,11 +164,12 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
        detail::parser_callback_t<basic_json>cb = nullptr,
        const bool allow_exceptions = true,
        const bool ignore_comments = false,
-        const bool ignore_trailing_commas = false
+        const bool ignore_trailing_commas = false,
+        const bool discard_number_values = false
    )
    {
        return ::nlohmann::detail::parser<basic_json, InputAdapterType>(std::move(adapter),
-               std::move(cb), allow_exceptions, ignore_comments, ignore_trailing_commas);
+               std::move(cb), allow_exceptions, ignore_comments, ignore_trailing_commas, discard_number_values);
    }

  private:
@@ -403,18 +404,6 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec

    /// @}

-    // Two template parameter requirements that would otherwise be silently
-    // violated: neither produces a diagnostic of its own, and both corrupt
-    // values rather than failing.
-
-    static_assert(sizeof(typename BinaryType::value_type) == 1,
-                  "BinaryType::value_type must be exactly one byte wide, "
-                  "because the binary readers and writers reinterpret the container's storage as raw bytes");
-
-    static_assert(sizeof(NumberUnsignedType) >= sizeof(NumberIntegerType),
-                  "NumberUnsignedType must be at least as wide as NumberIntegerType, "
-                  "because it has to hold the absolute value of every NumberIntegerType value");
-
  private:

    /// helper for exception-safe object creation
@@ -795,76 +784,21 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
        return it;
    }

-    /// @brief erase an element from the object and return the following one
-    /// Not every map returns an iterator from erase(iterator): some containers
-    /// (e.g., Abseil's hash maps) return void to avoid computing a successor
-    /// the caller may not need. Compute it before erasing for those.
-    template < typename It, detail::enable_if_t <
-                   !detail::erase_returns_void<object_t, It>::value, int > = 0 >
-    typename object_t::iterator erase_from_object(It pos)
-    {
-        return m_data.m_value.object->erase(pos);
-    }
-
-    template < typename It, detail::enable_if_t <
-                   detail::erase_returns_void<object_t, It>::value, int > = 0 >
-    typename object_t::iterator erase_from_object(It pos)
-    {
-        auto next = std::next(pos);
-        m_data.m_value.object->erase(pos);
-        return next;
-    }
-
-    /// @brief the capacity of the stored array, or unknown_size()
-    /// Only JSON_DIAGNOSTICS uses the value, to detect a reallocation that
-    /// would invalidate the parent pointers. Array types that do not have a
-    /// capacity() member function report unknown_size(), which is treated as
-    /// "the elements may have moved".
-#if JSON_DIAGNOSTICS
-    template < typename A = array_t, detail::enable_if_t < detail::has_capacity<A>::value, int > = 0 >
-    std::size_t array_capacity() const noexcept
-    {
-        return m_data.m_value.array->capacity();
-    }
-
-    template < typename A = array_t, detail::enable_if_t < !detail::has_capacity<A>::value, int > = 0 >
-    std::size_t array_capacity() const noexcept
-    {
-        return detail::unknown_size();
-    }
-#else
-    static constexpr std::size_t array_capacity() noexcept
-    {
-        return detail::unknown_size();
-    }
-#endif
-
-    /// @brief set the parent of a value that has just been added to an array
-    /// @param j the added value
-    /// @param old_capacity the value @ref array_capacity() returned before the
-    ///        insertion
-    reference set_parent_after_array_insert(reference j, std::size_t old_capacity)
+    reference set_parent(reference j, std::size_t old_capacity = detail::unknown_size())
    {
 #if JSON_DIAGNOSTICS
-        // see https://github.com/nlohmann/json/issues/2838
-        JSON_ASSERT(type() == value_t::array);
-        if (JSON_HEDLEY_UNLIKELY(old_capacity == detail::unknown_size()
-                                 || array_capacity() != old_capacity))
+        if (old_capacity != detail::unknown_size())
        {
-            // the capacity has changed, or the array type does not let us tell:
-            // the elements may have moved, so update all parents
-            set_parents();
-            return j;
+            // see https://github.com/nlohmann/json/issues/2838
+            JSON_ASSERT(type() == value_t::array);
+            if (JSON_HEDLEY_UNLIKELY(m_data.m_value.array->capacity() != old_capacity))
+            {
+                // capacity has changed: update all parents
+                set_parents();
+                return j;
+            }
        }
-#else
-        static_cast<void>(old_capacity);
-#endif
-        return set_parent(j);
-    }

-    reference set_parent(reference j)
-    {
-#if JSON_DIAGNOSTICS
        // ordered_json uses a vector internally, so pointers could have
        // been invalidated; see https://github.com/nlohmann/json/issues/2962
 #ifdef JSON_HEDLEY_MSVC_VERSION
@@ -883,6 +817,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
        j.m_parent = this;
 #else
        static_cast<void>(j);
+        static_cast<void>(old_capacity);
 #endif
        return j;
    }
@@ -1401,6 +1336,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec

    /// @brief serialization
    /// @sa https://json.nlohmann.me/api/basic_json/dump/
+    JSON_HEDLEY_WARN_UNUSED_RESULT
    string_t dump(const int indent = -1,
                  const char indent_char = ' ',
                  const bool ensure_ascii = false,
@@ -1423,6 +1359,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec

    /// @brief return the type of the JSON value (explicit)
    /// @sa https://json.nlohmann.me/api/basic_json/type/
+    JSON_HEDLEY_WARN_UNUSED_RESULT
    constexpr value_t type() const noexcept
    {
        return m_data.m_type;
@@ -1430,6 +1367,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec

    /// @brief return whether type is primitive
    /// @sa https://json.nlohmann.me/api/basic_json/is_primitive/
+    JSON_HEDLEY_WARN_UNUSED_RESULT
    constexpr bool is_primitive() const noexcept
    {
        return is_null() || is_string() || is_boolean() || is_number() || is_binary();
@@ -1437,6 +1375,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec

    /// @brief return whether type is structured
    /// @sa https://json.nlohmann.me/api/basic_json/is_structured/
+    JSON_HEDLEY_WARN_UNUSED_RESULT
    constexpr bool is_structured() const noexcept
    {
        return is_array() || is_object();
@@ -1444,6 +1383,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec

    /// @brief return whether value is null
    /// @sa https://json.nlohmann.me/api/basic_json/is_null/
+    JSON_HEDLEY_WARN_UNUSED_RESULT
    constexpr bool is_null() const noexcept
    {
        return m_data.m_type == value_t::null;
@@ -1451,6 +1391,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec

    /// @brief return whether value is a boolean
    /// @sa https://json.nlohmann.me/api/basic_json/is_boolean/
+    JSON_HEDLEY_WARN_UNUSED_RESULT
    constexpr bool is_boolean() const noexcept
    {
        return m_data.m_type == value_t::boolean;
@@ -1458,6 +1399,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec

    /// @brief return whether value is a number
    /// @sa https://json.nlohmann.me/api/basic_json/is_number/
+    JSON_HEDLEY_WARN_UNUSED_RESULT
    constexpr bool is_number() const noexcept
    {
        return is_number_integer() || is_number_float();
@@ -1465,6 +1407,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec

    /// @brief return whether value is an integer number
    /// @sa https://json.nlohmann.me/api/basic_json/is_number_integer/
+    JSON_HEDLEY_WARN_UNUSED_RESULT
    constexpr bool is_number_integer() const noexcept
    {
        return m_data.m_type == value_t::number_integer || m_data.m_type == value_t::number_unsigned;
@@ -1472,6 +1415,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec

    /// @brief return whether value is an unsigned integer number
    /// @sa https://json.nlohmann.me/api/basic_json/is_number_unsigned/
+    JSON_HEDLEY_WARN_UNUSED_RESULT
    constexpr bool is_number_unsigned() const noexcept
    {
        return m_data.m_type == value_t::number_unsigned;
@@ -1479,6 +1423,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec

    /// @brief return whether value is a floating-point number
    /// @sa https://json.nlohmann.me/api/basic_json/is_number_float/
+    JSON_HEDLEY_WARN_UNUSED_RESULT
    constexpr bool is_number_float() const noexcept
    {
        return m_data.m_type == value_t::number_float;
@@ -1486,6 +1431,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec

    /// @brief return whether value is an object
    /// @sa https://json.nlohmann.me/api/basic_json/is_object/
+    JSON_HEDLEY_WARN_UNUSED_RESULT
    constexpr bool is_object() const noexcept
    {
        return m_data.m_type == value_t::object;
@@ -1493,6 +1439,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec

    /// @brief return whether value is an array
    /// @sa https://json.nlohmann.me/api/basic_json/is_array/
+    JSON_HEDLEY_WARN_UNUSED_RESULT
    constexpr bool is_array() const noexcept
    {
        return m_data.m_type == value_t::array;
@@ -1500,6 +1447,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec

    /// @brief return whether value is a string
    /// @sa https://json.nlohmann.me/api/basic_json/is_string/
+    JSON_HEDLEY_WARN_UNUSED_RESULT
    constexpr bool is_string() const noexcept
    {
        return m_data.m_type == value_t::string;
@@ -1507,6 +1455,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec

    /// @brief return whether value is a binary array
    /// @sa https://json.nlohmann.me/api/basic_json/is_binary/
+    JSON_HEDLEY_WARN_UNUSED_RESULT
    constexpr bool is_binary() const noexcept
    {
        return m_data.m_type == value_t::binary;
@@ -1514,6 +1463,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec

    /// @brief return whether value is discarded
    /// @sa https://json.nlohmann.me/api/basic_json/is_discarded/
+    JSON_HEDLEY_WARN_UNUSED_RESULT
    constexpr bool is_discarded() const noexcept
    {
        return m_data.m_type == value_t::discarded;
@@ -2075,17 +2025,22 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
    reference at(size_type idx)
    {
        // at only works for arrays
-        if (JSON_HEDLEY_UNLIKELY(!is_array()))
+        if (JSON_HEDLEY_LIKELY(is_array()))
+        {
+            JSON_TRY
+            {
+                return set_parent(m_data.m_value.array->at(idx));
+            }
+            JSON_CATCH (std::out_of_range&)
+            {
+                // create a better exception explanation
+                JSON_THROW(out_of_range::create(401, detail::concat("array index ", std::to_string(idx), " is out of range"), this));
+            } // cppcheck-suppress[missingReturn]
+        }
+        else
        {
            JSON_THROW(type_error::create(304, detail::concat("cannot use at() with ", type_name()), this));
        }
-
-        if (JSON_HEDLEY_UNLIKELY(idx >= m_data.m_value.array->size()))
-        {
-            JSON_THROW(out_of_range::create(401, detail::concat("array index ", std::to_string(idx), " is out of range"), this));
-        }
-
-        return set_parent((*m_data.m_value.array)[idx]);
    }

    /// @brief access specified array element with bounds checking
@@ -2093,17 +2048,22 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
    const_reference at(size_type idx) const
    {
        // at only works for arrays
-        if (JSON_HEDLEY_UNLIKELY(!is_array()))
+        if (JSON_HEDLEY_LIKELY(is_array()))
+        {
+            JSON_TRY
+            {
+                return m_data.m_value.array->at(idx);
+            }
+            JSON_CATCH (std::out_of_range&)
+            {
+                // create a better exception explanation
+                JSON_THROW(out_of_range::create(401, detail::concat("array index ", std::to_string(idx), " is out of range"), this));
+            } // cppcheck-suppress[missingReturn]
+        }
+        else
        {
            JSON_THROW(type_error::create(304, detail::concat("cannot use at() with ", type_name()), this));
        }
-
-        if (JSON_HEDLEY_UNLIKELY(idx >= m_data.m_value.array->size()))
-        {
-            JSON_THROW(out_of_range::create(401, detail::concat("array index ", std::to_string(idx), " is out of range"), this));
-        }
-
-        return (*m_data.m_value.array)[idx];
    }

    /// @brief access specified object element with bounds checking
@@ -2203,13 +2163,12 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
 #if JSON_DIAGNOSTICS
                // remember array size & capacity before resizing
                const auto old_size = m_data.m_value.array->size();
-                const auto old_capacity = array_capacity();
+                const auto old_capacity = m_data.m_value.array->capacity();
 #endif
                m_data.m_value.array->resize(idx + 1);

 #if JSON_DIAGNOSTICS
-                if (JSON_HEDLEY_UNLIKELY(old_capacity == detail::unknown_size()
-                                         || array_capacity() != old_capacity))
+                if (JSON_HEDLEY_UNLIKELY(m_data.m_value.array->capacity() != old_capacity))
                {
                    // capacity has changed: update all parents
                    set_parents();
@@ -2600,7 +2559,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec

            case value_t::object:
            {
-                result.m_it.object_iterator = erase_from_object(pos.m_it.object_iterator);
+                result.m_it.object_iterator = m_data.m_value.object->erase(pos.m_it.object_iterator);
                break;
            }

@@ -2836,6 +2795,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec

    /// @brief returns the number of occurrences of a key in a JSON object
    /// @sa https://json.nlohmann.me/api/basic_json/count/
+    JSON_HEDLEY_WARN_UNUSED_RESULT
    size_type count(const typename object_t::key_type& key) const
    {
        // return 0 for all nonobject types
@@ -2846,6 +2806,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
    /// @sa https://json.nlohmann.me/api/basic_json/count/
    template<class KeyType, detail::enable_if_t<
                 detail::is_usable_as_basic_json_key_type<basic_json_t, KeyType>::value, int> = 0>
+    JSON_HEDLEY_WARN_UNUSED_RESULT
    size_type count(KeyType && key) const
    {
        // return 0 for all nonobject types
@@ -2854,6 +2815,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec

    /// @brief check the existence of an element in a JSON object
    /// @sa https://json.nlohmann.me/api/basic_json/contains/
+    JSON_HEDLEY_WARN_UNUSED_RESULT
    bool contains(const typename object_t::key_type& key) const
    {
        return is_object() && m_data.m_value.object->find(key) != m_data.m_value.object->end();
@@ -2863,6 +2825,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
    /// @sa https://json.nlohmann.me/api/basic_json/contains/
    template<class KeyType, detail::enable_if_t<
                 detail::is_usable_as_basic_json_key_type<basic_json_t, KeyType>::value, int> = 0>
+    JSON_HEDLEY_WARN_UNUSED_RESULT
    bool contains(KeyType && key) const
    {
        return is_object() && m_data.m_value.object->find(std::forward<KeyType>(key)) != m_data.m_value.object->end();
@@ -2870,12 +2833,14 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec

    /// @brief check the existence of an element in a JSON object given a JSON pointer
    /// @sa https://json.nlohmann.me/api/basic_json/contains/
+    JSON_HEDLEY_WARN_UNUSED_RESULT
    bool contains(const json_pointer& ptr) const
    {
        return ptr.contains(this);
    }

    template<typename BasicJsonType, detail::enable_if_t<detail::is_basic_json<BasicJsonType>::value, int> = 0>
+    JSON_HEDLEY_WARN_UNUSED_RESULT
    JSON_HEDLEY_DEPRECATED_FOR(3.11.0, basic_json::json_pointer or nlohmann::json_pointer<basic_json::string_t>) // NOLINT(readability/alt_tokens)
    bool contains(const typename ::nlohmann::json_pointer<BasicJsonType>& ptr) const
    {
@@ -3031,6 +2996,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec

    /// @brief checks whether the container is empty.
    /// @sa https://json.nlohmann.me/api/basic_json/empty/
+    JSON_HEDLEY_WARN_UNUSED_RESULT
    bool empty() const noexcept
    {
        switch (m_data.m_type)
@@ -3070,6 +3036,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec

    /// @brief returns the number of elements
    /// @sa https://json.nlohmann.me/api/basic_json/size/
+    JSON_HEDLEY_WARN_UNUSED_RESULT
    size_type size() const noexcept
    {
        switch (m_data.m_type)
@@ -3109,6 +3076,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec

    /// @brief returns the maximum possible number of elements
    /// @sa https://json.nlohmann.me/api/basic_json/max_size/
+    JSON_HEDLEY_WARN_UNUSED_RESULT
    size_type max_size() const noexcept
    {
        switch (m_data.m_type)
@@ -3230,9 +3198,9 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
        }

        // add the element to the array (move semantics)
-        const auto old_capacity = array_capacity();
+        const auto old_capacity = m_data.m_value.array->capacity();
        m_data.m_value.array->push_back(std::move(val));
-        set_parent_after_array_insert(m_data.m_value.array->back(), old_capacity);
+        set_parent(m_data.m_value.array->back(), old_capacity);
        // if val is moved from, basic_json move constructor marks it null, so we do not call the destructor
    }

@@ -3263,9 +3231,9 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
        }

        // add the element to the array
-        const auto old_capacity = array_capacity();
+        const auto old_capacity = m_data.m_value.array->capacity();
        m_data.m_value.array->push_back(val);
-        set_parent_after_array_insert(m_data.m_value.array->back(), old_capacity);
+        set_parent(m_data.m_value.array->back(), old_capacity);
    }

    /// @brief add an object to an array
@@ -3351,9 +3319,9 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
        }

        // add the element to the array (perfect forwarding)
-        const auto old_capacity = array_capacity();
+        const auto old_capacity = m_data.m_value.array->capacity();
        m_data.m_value.array->emplace_back(std::forward<Args>(args)...);
-        return set_parent_after_array_insert(m_data.m_value.array->back(), old_capacity);
+        return set_parent(m_data.m_value.array->back(), old_capacity);
    }

    /// @brief add an object to an object if key does not exist
@@ -3432,7 +3400,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
    /// @sa https://json.nlohmann.me/api/basic_json/insert/
    iterator insert(const_iterator pos, basic_json&& val) // NOLINT(performance-unnecessary-value-param)
    {
-        return insert(std::move(pos), val);
+        return insert(pos, val);
    }

    /// @brief inserts copies of element into array
@@ -3760,19 +3728,19 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
    }                                                                                                    \
    else if (lhs_type == value_t::number_integer && rhs_type == value_t::number_float)                   \
    {                                                                                                    \
-        return static_cast<number_float_t>(lhs.m_data.m_value.number_integer) op rhs.m_data.m_value.number_float;      \
+        return (detail::compare_integer_with_float(lhs.m_data.m_value.number_integer, rhs.m_data.m_value.number_float)) op (static_cast<number_float_t>(0)); \
    }                                                                                                    \
    else if (lhs_type == value_t::number_float && rhs_type == value_t::number_integer)                   \
    {                                                                                                    \
-        return lhs.m_data.m_value.number_float op static_cast<number_float_t>(rhs.m_data.m_value.number_integer);      \
+        return (static_cast<number_float_t>(0)) op (detail::compare_integer_with_float(rhs.m_data.m_value.number_integer, lhs.m_data.m_value.number_float)); \
    }                                                                                                    \
    else if (lhs_type == value_t::number_unsigned && rhs_type == value_t::number_float)                  \
    {                                                                                                    \
-        return static_cast<number_float_t>(lhs.m_data.m_value.number_unsigned) op rhs.m_data.m_value.number_float;     \
+        return (detail::compare_integer_with_float(lhs.m_data.m_value.number_unsigned, rhs.m_data.m_value.number_float)) op (static_cast<number_float_t>(0)); \
    }                                                                                                    \
    else if (lhs_type == value_t::number_float && rhs_type == value_t::number_unsigned)                  \
    {                                                                                                    \
-        return lhs.m_data.m_value.number_float op static_cast<number_float_t>(rhs.m_data.m_value.number_unsigned);     \
+        return (static_cast<number_float_t>(0)) op (detail::compare_integer_with_float(rhs.m_data.m_value.number_unsigned, lhs.m_data.m_value.number_float)); \
    }                                                                                                    \
    else if (lhs_type == value_t::number_unsigned && rhs_type == value_t::number_integer)                \
    {                                                                                                    \
@@ -3827,13 +3795,13 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
    bool operator==(const_reference rhs) const noexcept
    {
 #ifdef __GNUC__
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Wfloat-equal"
+        JSON_HEDLEY_DIAGNOSTIC_PUSH
+        JSON_HEDLEY_PRAGMA(GCC diagnostic ignored "-Wfloat-equal")
 #endif
        const_reference lhs = *this;
        JSON_IMPLEMENT_OPERATOR( ==, true, false, false)
 #ifdef __GNUC__
-#pragma GCC diagnostic pop
+        JSON_HEDLEY_DIAGNOSTIC_POP
 #endif
    }

@@ -3920,12 +3888,12 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
    friend bool operator==(const_reference lhs, const_reference rhs) noexcept
    {
 #ifdef __GNUC__
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Wfloat-equal"
+        JSON_HEDLEY_DIAGNOSTIC_PUSH
+        JSON_HEDLEY_PRAGMA(GCC diagnostic ignored "-Wfloat-equal")
 #endif
        JSON_IMPLEMENT_OPERATOR( ==, true, false, false)
 #ifdef __GNUC__
-#pragma GCC diagnostic pop
+        JSON_HEDLEY_DIAGNOSTIC_POP
 #endif
    }

@@ -4186,22 +4154,24 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
    /// @brief check if the input is valid JSON
    /// @sa https://json.nlohmann.me/api/basic_json/accept/
    template<typename InputType>
+    JSON_HEDLEY_WARN_UNUSED_RESULT
    static bool accept(InputType&& i,
                       const bool ignore_comments = false,
                       const bool ignore_trailing_commas = false)
    {
-        return parser(detail::input_adapter(std::forward<InputType>(i)), nullptr, false, ignore_comments, ignore_trailing_commas).accept(true);
+        return parser(detail::input_adapter(std::forward<InputType>(i)), nullptr, false, ignore_comments, ignore_trailing_commas, true).accept(true);
    }

    /// @brief check if the input is valid JSON (iterator pair, or iterator+sentinel pair for C++20 ranges support)
    /// @sa https://json.nlohmann.me/api/basic_json/accept/
    template<typename IteratorType, typename SentinelType = IteratorType,
             detail::enable_if_t<detail::can_compare_ne<IteratorType, SentinelType>::value, int> = 0>
+    JSON_HEDLEY_WARN_UNUSED_RESULT
    static bool accept(IteratorType first, SentinelType last,
                       const bool ignore_comments = false,
                       const bool ignore_trailing_commas = false)
    {
-        return parser(detail::input_adapter(std::move(first), std::move(last)), nullptr, false, ignore_comments, ignore_trailing_commas).accept(true);
+        return parser(detail::input_adapter(std::move(first), std::move(last)), nullptr, false, ignore_comments, ignore_trailing_commas, true).accept(true);
    }

    JSON_HEDLEY_WARN_UNUSED_RESULT
@@ -4210,7 +4180,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
                       const bool ignore_comments = false,
                       const bool ignore_trailing_commas = false)
    {
-        return parser(i.get(), nullptr, false, ignore_comments, ignore_trailing_commas).accept(true);
+        return parser(i.get(), nullptr, false, ignore_comments, ignore_trailing_commas, true).accept(true);
    }

    /// @brief generate SAX events
@@ -4296,6 +4266,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec

    /// @brief return the type as string
    /// @sa https://json.nlohmann.me/api/basic_json/type_name/
+    JSON_HEDLEY_WARN_UNUSED_RESULT
    JSON_HEDLEY_RETURNS_NON_NULL
    const char* type_name() const noexcept
    {
@@ -4996,6 +4967,36 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
                // note erase performs range check
                parent.erase(json_pointer::template array_index<basic_json_t>(last_path));
            }
+            else
+            {
+                // the parent of a "remove" target must be an object or array
+                // (see #5396)
+                JSON_THROW(out_of_range::create(413, detail::concat("cannot remove value: the JSON Patch 'remove' target's parent is of type ", parent.type_name(), ", but must be an object or array"), &parent));
+            }
+        };
+
+        // RFC 6902 (section 4.4) forbids "from" from being a proper prefix
+        // of "path" for a "move" operation: a location cannot be moved into
+        // one of its own children. Compares reference tokens (already
+        // unescaped by json_pointer's parser) rather than the raw pointer
+        // strings, since a token may itself contain an escaped '/' or '~'
+        // that would defeat a naive string-prefix comparison. "from" equal
+        // to "path" is *not* a proper prefix and must return false.
+        const auto is_proper_prefix = [](const json_pointer & from, const json_pointer & to)
+        {
+            const auto from_size = from.reference_tokens.size();
+            if (from_size >= to.reference_tokens.size())
+            {
+                return false;
+            }
+            for (std::size_t i = 0; i < from_size; ++i)
+            {
+                if (!(from.reference_tokens[i] == to.reference_tokens[i]))
+                {
+                    return false;
+                }
+            }
+            return true;
        };

        // type check: top level value must be an array
@@ -5073,6 +5074,11 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
                    const auto from_path = get_value("move", "from", true).template get<string_t>();
                    json_pointer from_ptr(from_path);

+                    if (JSON_HEDLEY_UNLIKELY(is_proper_prefix(from_ptr, ptr)))
+                    {
+                        JSON_THROW(out_of_range::create(414, detail::concat("cannot move value: 'from' path '", from_path, "' is a proper prefix of 'path' '", path, "'"), &result));
+                    }
+
                    // the "from" location must exist - use at()
                    basic_json const v = result.at(from_ptr);

@@ -5185,19 +5191,17 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
                // We now reached the end of at least one array
                // in a second pass, traverse the remaining elements

-                // remove my remaining elements
-                const auto end_index = static_cast<difference_type>(result.size());
-                while (i < source.size())
+                // remove my remaining elements, highest index first; appending
+                // in that order avoids the quadratic reinsertion done before
+                for (std::size_t j = source.size(); j > i; --j)
                {
-                    // add operations in reverse order to avoid invalid
-                    // indices
-                    result.insert(result.begin() + end_index, object(
+                    result.push_back(object(
                    {
                        {"op", "remove"},
-                        {"path", detail::concat<string_t>(path, '/', detail::to_string<string_t>(i))}
+                        {"path", detail::concat<string_t>(path, '/', detail::to_string<string_t>(j - 1))}
                    }));
-                    ++i;
                }
+                i = source.size();

                // add other remaining elements
                while (i < target.size())
@@ -17,7 +17,7 @@
 #undef JSON_HEDLEY_CLANG_HAS_ATTRIBUTE
 #undef JSON_HEDLEY_CLANG_HAS_BUILTIN
 #undef JSON_HEDLEY_CLANG_HAS_CPP_ATTRIBUTE
-#undef JSON_HEDLEY_CLANG_HAS_DECLSPEC_DECLSPEC_ATTRIBUTE
+#undef JSON_HEDLEY_CLANG_HAS_DECLSPEC_ATTRIBUTE
 #undef JSON_HEDLEY_CLANG_HAS_EXTENSION
 #undef JSON_HEDLEY_CLANG_HAS_FEATURE
 #undef JSON_HEDLEY_CLANG_HAS_WARNING
@@ -108,7 +108,10 @@
 #undef JSON_HEDLEY_PELLES_VERSION_CHECK
 #undef JSON_HEDLEY_PGI_VERSION
 #undef JSON_HEDLEY_PGI_VERSION_CHECK
+#undef JSON_HEDLEY_PRAGMA
 #undef JSON_HEDLEY_PREDICT
+#undef JSON_HEDLEY_PREDICT_FALSE
+#undef JSON_HEDLEY_PREDICT_TRUE
 #undef JSON_HEDLEY_PRINTF_FORMAT
 #undef JSON_HEDLEY_PRIVATE
 #undef JSON_HEDLEY_PUBLIC
@@ -125,6 +125,51 @@ json_test_set_test_options(test-unicode4 TEST_PROPERTIES TIMEOUT 3000)
 # add unit tests
 #############################################################################

+# Generate the leak checks for every JSON_HEDLEY_* macro defined in
+# hedley.hpp; tests/src/unit-no-macro-leak.cpp #include-s the result after
+# nlohmann/json.hpp (see issue #5408). Using the shared
+# cmake/scripts/gen_hedley_undef_check.cmake script (also used by `make
+# update_hedley_undef`) instead of a hand-maintained list of macro names
+# means this test can never go stale after a future `make update_hedley`.
+set(hedley_hpp "${PROJECT_SOURCE_DIR}/include/nlohmann/thirdparty/hedley/hedley.hpp")
+set(hedley_undef_check_script "${PROJECT_SOURCE_DIR}/cmake/scripts/gen_hedley_undef_check.cmake")
+set(hedley_undef_checks "${PROJECT_BINARY_DIR}/include/hedley_undef_checks.inc")
+
+# Reconfigure whenever the vendored header or the generator script changes,
+# so a `cmake --build` after `make update_hedley` does not silently keep a
+# stale generated file around.
+set_property(DIRECTORY APPEND PROPERTY CMAKE_CONFIGURE_DEPENDS
+    "${hedley_hpp}"
+    "${hedley_undef_check_script}")
+
+# Generate once at configure time, so the very first build (before any
+# custom-command build step has run) already has an up-to-date file.
+execute_process(
+    COMMAND ${CMAKE_COMMAND}
+        "-DHEDLEY_HPP=${hedley_hpp}"
+        "-DOUTPUT=${hedley_undef_checks}"
+        -DMODE=checks
+        -P "${hedley_undef_check_script}"
+    RESULT_VARIABLE hedley_undef_check_result
+)
+if(NOT hedley_undef_check_result EQUAL 0)
+    message(FATAL_ERROR "Failed to generate ${hedley_undef_checks}")
+endif()
+
+# Also (re)generate as a build step, so an incremental build after editing
+# hedley.hpp without a full reconfigure still picks up the change.
+add_custom_command(
+    OUTPUT "${hedley_undef_checks}"
+    COMMAND ${CMAKE_COMMAND}
+        "-DHEDLEY_HPP=${hedley_hpp}"
+        "-DOUTPUT=${hedley_undef_checks}"
+        -DMODE=checks
+        -P "${hedley_undef_check_script}"
+    DEPENDS "${hedley_hpp}" "${hedley_undef_check_script}"
+    COMMENT "Generating Hedley undef leak checks"
+    VERBATIM)
+add_custom_target(generate_hedley_undef_checks DEPENDS "${hedley_undef_checks}")
+
 if("${JSON_TestStandards}" STREQUAL "")
    set(test_cxx_standards 11 14 17 20 23)
    unset(test_force)
@@ -163,6 +208,14 @@ foreach(file ${files})
    json_test_add_test_for(${file} MAIN test_main CXX_STANDARDS ${test_cxx_standards} ${test_force})
 endforeach()

+# tests/src/unit-no-macro-leak.cpp #include-s the generated leak-check file,
+# so its test targets must be built after generate_hedley_undef_checks.
+foreach(cxx_standard ${test_cxx_standards})
+    if(TARGET test-no-macro-leak_cpp${cxx_standard})
+        add_dependencies(test-no-macro-leak_cpp${cxx_standard} generate_hedley_undef_checks)
+    endif()
+endforeach()
+
 if(json_32bit_test_only)
    # Skip all other tests in this file
    return()
@@ -21,6 +21,27 @@ array data, it performs the following steps:
 - j4 = from_bjdata(vec3)
 - assert(j1 == j4)

+Re-serializing j2/j3/j4 with the same use_size/use_type settings is checked
+for value-stability rather than byte-exact stability: from_bjdata(to_bjdata(j2))
+must equal j2 (and likewise for j3, j4). Byte-exact stability does not hold in
+general, because a BJData value can lose type fidelity across a round trip
+(e.g. a binary_t value serialized without the optimized "$U#" array header is
+parsed back as a plain array of numbers, see #5398 and the discussion on
+PR #5494) - the numeric value is preserved, but the writer's smallest-type
+selection for the now-plain numbers may legitimately pick a different, but
+equally valid, single-byte type marker than the dedicated binary-data writer
+would have. Both encodings are valid BJData and both decode to the same
+value, so this is not treated as a round-trip failure here.
+
+"Value-stable" is checked by comparing dump()s rather than with operator==
+directly: a BJData/UBJSON payload can decode to a non-finite double (NaN or
+-Infinity), and IEEE 754 NaN is never equal to itself, so operator== would
+report two structurally-identical trees as different whenever a NaN is
+involved -- not a round-trip bug, just NaN's ordinary (non-)reflexivity.
+dump() serializes any non-finite double the same deterministic way (as JSON
+`null`, since JSON itself cannot represent NaN/Infinity), so comparing
+dumps is stable under exactly the same values that break operator==.
+
 The provided function `LLVMFuzzerTestOneInput` can be used in different fuzzer
 drivers.
 */
@@ -31,6 +52,13 @@ drivers.

 using json = nlohmann::json;

+// value-stable comparison for the round-trip checks below; see the note
+// above on why this compares dump()s rather than the json values directly
+static bool is_value_stable(const json& lhs, const json& rhs)
+{
+    return lhs.dump() == rhs.dump();
+}
+
 // see http://llvm.org/docs/LibFuzzer.html
 extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size)
 {
@@ -56,10 +84,12 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size)
            json const j3 = json::from_bjdata(vec3);
            json const j4 = json::from_bjdata(vec4);

-            // serializations must match
-            assert(json::to_bjdata(j2, false, false) == vec2);
-            assert(json::to_bjdata(j3, true, false) == vec3);
-            assert(json::to_bjdata(j4, true, true) == vec4);
+            // re-serializing must be value-stable (see the notes above on
+            // why byte-exact stability is not guaranteed in general, and
+            // why this compares dump()s rather than the values directly)
+            assert(is_value_stable(json::from_bjdata(json::to_bjdata(j2, false, false)), j2));
+            assert(is_value_stable(json::from_bjdata(json::to_bjdata(j3, true, false)), j3));
+            assert(is_value_stable(json::from_bjdata(json::to_bjdata(j4, true, true)), j4));
        }
        catch (const json::parse_error&)
        {
@@ -15,6 +15,15 @@
 namespace utils
 {

+// Some tests intentionally discard the [[nodiscard]]/JSON_HEDLEY_WARN_UNUSED_RESULT
+// return value of a call they only make to exercise its side effects (e.g. checking
+// that it does not throw). A plain (void) cast on the call expression does not
+// suppress GCC's warning for functions using the GNU __attribute__((warn_unused_result))
+// form (as opposed to the C++17 [[nodiscard]] attribute) -- passing the value into an
+// ordinary function call does.
+template<typename T>
+inline void ignore_return_value(T&& /*unused*/) noexcept {}
+
 inline std::vector<std::uint8_t> read_binary_file(const std::string& filename)
 {
    std::ifstream file(filename, std::ios::binary);
@@ -11,10 +11,8 @@

 #include <nlohmann/json.hpp>

-#include <cstdint>
 #include <string>
 #include <utility>
-#include <vector>

 /* forward declarations */
 class alt_string;
@@ -24,10 +22,6 @@ void int_to_string(alt_string& target, std::size_t value); // NOLINT(misc-use-in
 /*
 * This is virtually a string class.
 * It covers std::string under the hood.
- *
- * It deliberately does not provide c_str(), back(), find(str, pos), replace(),
- * or substr(): the library must not rely on them. Do not add members here
- * without checking that the library actually needs them.
 */
 class alt_string
 {
@@ -112,6 +106,11 @@ class alt_string
        return str_impl < op.str_impl;
    }

+    const char* c_str() const
+    {
+        return str_impl.c_str();
+    }
+
    char& operator[](std::size_t index)
    {
        return str_impl[index];
@@ -122,6 +121,16 @@ class alt_string
        return str_impl[index];
    }

+    char& back()
+    {
+        return str_impl.back();
+    }
+
+    const char& back() const
+    {
+        return str_impl.back();
+    }
+
    void clear()
    {
        str_impl.clear();
@@ -137,11 +146,28 @@ class alt_string
        return str_impl.empty();
    }

+    std::size_t find(const alt_string& str, std::size_t pos = 0) const
+    {
+        return str_impl.find(str.str_impl, pos);
+    }
+
    std::size_t find_first_of(char c, std::size_t pos = 0) const
    {
        return str_impl.find_first_of(c, pos);
    }

+    alt_string substr(std::size_t pos = 0, std::size_t count = npos) const
+    {
+        const std::string s = str_impl.substr(pos, count);
+        return {s.data(), s.size()};
+    }
+
+    alt_string& replace(std::size_t pos, std::size_t count, const alt_string& str)
+    {
+        str_impl.replace(pos, count, str.str_impl);
+        return *this;
+    }
+
    void reserve( std::size_t new_cap = 0 )
    {
        str_impl.reserve(new_cap);
@@ -176,31 +202,6 @@ bool operator<(const char* op1, const alt_string& op2) noexcept

 TEST_CASE("alternative string type")
 {
-    SECTION("binary formats")
-    {
-        alt_json doc;
-        doc["pi"] = 3.141;
-        doc["happy"] = true;
-        doc["list"] = {1, 2, 3};
-
-        CHECK(alt_json::from_cbor(alt_json::to_cbor(doc)) == doc);
-        CHECK(alt_json::from_msgpack(alt_json::to_msgpack(doc)) == doc);
-        // BSON is not covered: it additionally needs string_t::find(value_type),
-        // which alt_string does not provide
-        CHECK(alt_json::from_ubjson(alt_json::to_ubjson(doc)) == doc);
-
-        // a UBJSON high-precision number is parsed into a std::string that the
-        // reader has to hand to the SAX interface as an alt_string
-        const std::vector<uint8_t> high_precision =
-        {
-            'H', 'i', 0x16, '3', '.', '1', '4', '1', '5', '9', '2', '6', '5', '3',
-            '5', '8', '9', '7', '9', '3', '2', '3', '8', '4', '6'
-        };
-        const auto number = alt_json::from_ubjson(high_precision);
-        CHECK(number.is_number_float());
-        CHECK(number.get<double>() == doctest::Approx(3.14159265358979323846));
-    }
-
    SECTION("dump")
    {
        {
@@ -331,15 +332,6 @@ TEST_CASE("alternative string type")

        CHECK(j.at(alt_json::json_pointer("/foo/0")) == j["foo"][0]);
        CHECK(j.at(alt_json::json_pointer("/foo/1")) == j["foo"][1]);
-
-        // RFC 6901 escaping works without string_t::find(str, pos), replace(),
-        // and substr()
-        auto j2 = alt_json::parse(R"({"a/b": 1, "m~n": 2, "~/~~//": 3})");
-        CHECK(j2.at(alt_json::json_pointer("/a~1b")) == 1);
-        CHECK(j2.at(alt_json::json_pointer("/m~0n")) == 2);
-        CHECK(j2.at(alt_json::json_pointer("/~0~1~0~0~1~1")) == 3);
-        CHECK(alt_json::json_pointer("/~0~1~0~0~1~1").to_string() == alt_string("/~0~1~0~0~1~1"));
-        CHECK(j2.flatten().unflatten() == j2);
    }

    SECTION("patch")
@@ -2586,7 +2586,12 @@ TEST_CASE("BJData")
                CHECK(json::to_bjdata(json::from_bjdata(v_d), true, true) == v_d);
                CHECK(json::to_bjdata(json::from_bjdata(v_D), true, true) == v_D);
                CHECK(json::to_bjdata(json::from_bjdata(v_C), true, true) == v_C);
-                CHECK(json::to_bjdata(json::from_bjdata(v_B), true, true) == v_B);
+                // v_B uses the Draft-3-only 'B' marker, so it round-trips only when
+                // Draft 3 is explicitly selected (see GitHub issue #5404); the
+                // default Draft 2 falls back to a plain object instead, covered by
+                // the "ndarray with _ArrayType_ "byte" is gated by the BJData draft
+                // version" section below
+                CHECK(json::to_bjdata(json::from_bjdata(v_B), true, true, json::bjdata_version_t::draft3) == v_B);
            }

            SECTION("ndarray with data not matching _ArrayType_ is written as an object")
@@ -2629,8 +2634,10 @@ TEST_CASE("BJData")
                // the C++ API stores an int literal as number_integer, so _ArrayType_
                // names the wire type rather than the storage. Both storages have to
                // produce the same typed array for every type.
+                // "byte" is checked separately below since it additionally requires
+                // BJData Draft 3 to be selected explicitly (see GitHub issue #5404).
                for (const char* type :
-                        {"uint8", "int8", "uint16", "int16", "uint32", "int32", "uint64", "int64", "char", "byte"
+                        {"uint8", "int8", "uint16", "int16", "uint32", "int32", "uint64", "int64", "char"
                        })
                {
                    CAPTURE(type);
@@ -2641,6 +2648,14 @@ TEST_CASE("BJData")
                    CHECK(from_text == json::to_bjdata(json({{"_ArrayType_", type}, {"_ArraySize_", {2, 3}}, {"_ArrayData_", {1, 2, 3, 4, 5, 6}}})));
                }

+                {
+                    const std::string text = R"({"_ArrayType_":"byte","_ArraySize_":[2,3],"_ArrayData_":[1,2,3,4,5,6]})";
+                    const auto from_text = json::to_bjdata(json::parse(text), true, true, json::bjdata_version_t::draft3);
+                    CHECK(from_text.at(0) == '[');
+                    CHECK(from_text == json::to_bjdata(json({{"_ArrayType_", "byte"}, {"_ArraySize_", {2, 3}}, {"_ArrayData_", {1, 2, 3, 4, 5, 6}}}),
+                    true, true, json::bjdata_version_t::draft3));
+                }
+
                // negative values under a signed type behave the same way
                const auto from_neg = json::to_bjdata(json::parse(R"({"_ArrayType_":"int32","_ArraySize_":[2],"_ArrayData_":[-5,7]})"));
                CHECK(from_neg.at(0) == '[');
@@ -2731,6 +2746,83 @@ TEST_CASE("BJData")
                CHECK(json::from_bjdata(json::to_bjdata(j_size), true, true) == j_size);
            }

+            SECTION("ndarray whose _ArrayType_ is not a string stays as object")
+            {
+                // the type name is looked up as a string below the annotation
+                // check; a non-string _ArrayType_ cannot name a known dtype,
+                // so calling get<string_t>() on it would throw type_error.302
+                // instead of falling back like an unrecognized type name
+                // already does (see GitHub issue #5398)
+                json const j_number = json({{"_ArrayType_", 1}, {"_ArraySize_", {2}}, {"_ArrayData_", {1, 2}}});
+                const auto out_number = json::to_bjdata(j_number);
+                CHECK(out_number.at(0) == '{');
+                CHECK(json::from_bjdata(out_number) == j_number);
+
+                json const j_null = json({{"_ArrayType_", nullptr}, {"_ArraySize_", {2}}, {"_ArrayData_", {1, 2}}});
+                const auto out_null = json::to_bjdata(j_null);
+                CHECK(out_null.at(0) == '{');
+                CHECK(json::from_bjdata(out_null) == j_null);
+
+                json const j_bool = json({{"_ArrayType_", true}, {"_ArraySize_", {2}}, {"_ArrayData_", {1, 2}}});
+                const auto out_bool = json::to_bjdata(j_bool);
+                CHECK(out_bool.at(0) == '{');
+                CHECK(json::from_bjdata(out_bool) == j_bool);
+
+                json const j_array = json({{"_ArrayType_", {"uint8"}}, {"_ArraySize_", {2}}, {"_ArrayData_", {1, 2}}});
+                const auto out_array = json::to_bjdata(j_array);
+                CHECK(out_array.at(0) == '{');
+                CHECK(json::from_bjdata(out_array) == j_array);
+
+                json const j_object = json({{"_ArrayType_", {{"a", 1}}}, {"_ArraySize_", {2}}, {"_ArrayData_", {1, 2}}});
+                const auto out_object = json::to_bjdata(j_object);
+                CHECK(out_object.at(0) == '{');
+                CHECK(json::from_bjdata(out_object) == j_object);
+            }
+
+            SECTION("re-serializing a value containing a plain-array-of-bytes is value-stable but not byte-stable")
+            {
+                // OSS-Fuzz found this input (an array whose first element is a
+                // binary_t byte, followed by an object whose _ArrayType_ is
+                // not a string) while exercising the fix for #5398 above: once
+                // the fix stops to_bjdata() from throwing type_error.302 for
+                // the third element, serialization proceeds far enough to
+                // reach a pre-existing, unrelated round-trip quirk in how a
+                // single-byte binary_t value is re-encoded.
+                std::vector<std::uint8_t> const input
+                {
+                    0x5b, 0x5b, 0x24, 0x42, 0x23, 0x5b, 0x69, 0x01, 0x5d, 0x5b, 0x5b, 0x5d, 0x7b, 0x55, 0x0b,
+                    0x5f, 0x41, 0x72, 0x72, 0x61, 0x79, 0x44, 0x61, 0x74, 0x61, 0x5f, 0x54, 0x55, 0x0b, 0x5f,
+                    0x41, 0x72, 0x72, 0x61, 0x79, 0x53, 0x69, 0x7a, 0x65, 0x5f, 0x5a, 0x55, 0x0b, 0x5f, 0x41,
+                    0x72, 0x72, 0x61, 0x79, 0x54, 0x79, 0x70, 0x65, 0x5f, 0x54, 0x7d, 0x5d
+                };
+                json const j1 = json::from_bjdata(input);
+
+                // to_bjdata() must not throw (this is what #5398 fixes)
+                std::vector<std::uint8_t> vec2;
+                CHECK_NOTHROW(vec2 = json::to_bjdata(j1, false, false));
+
+                // parsing back a plain (non-optimized) array of bytes cannot
+                // recover that it used to be a binary_t: from_bjdata() has no
+                // way to distinguish "array of uint8 numbers" from "array of
+                // bytes" unless the compact "$U#" array header is used, so
+                // the binary_t collapses into a plain JSON array
+                json const j2 = json::from_bjdata(vec2);
+                CHECK(j1 != j2);
+                CHECK(j2 == json({{91}, json::array(), {{"_ArrayData_", true}, {"_ArraySize_", nullptr}, {"_ArrayType_", true}}}));
+
+                // re-serializing j2 no longer goes through the dedicated
+                // binary_t writer (which always uses the 'U' marker for raw
+                // bytes); the now-plain number 91 goes through the generic
+                // smallest-type writer instead, which - like the rest of the
+                // UBJSON/BJData writer, and unchanged by this fix - prefers
+                // the 'i' (int8) marker over 'U' (uint8) for values that fit
+                // both. Both markers are valid BJData and both decode back to
+                // 91, so this is not byte-for-byte identical to vec2, but it
+                // is value-stable: parsing it again reproduces j2 exactly.
+                std::vector<std::uint8_t> const vec3 = json::to_bjdata(j2, false, false);
+                CHECK(json::from_bjdata(vec3) == j2);
+            }
+
            SECTION("ndarray whose dimensions overflow stays as object")
            {
                // the product of the dimensions wraps around std::size_t to 0
@@ -2751,6 +2843,108 @@ TEST_CASE("BJData")
                CHECK(json::to_bjdata(j_ok) == std::vector<uint8_t>({'[', '$', 'U', '#', '[', 'i', 2, 'i', 3, ']', 1, 2, 3, 4, 5, 6}));
                CHECK(json::from_bjdata(json::to_bjdata(j_ok), true, true) == j_ok);
            }
+
+            SECTION("ndarray whose _ArraySize_ is not an array stays as object")
+            {
+                // the shape is written verbatim as the header length, so a
+                // value that is not an array cannot produce a valid one: null
+                // would emit 'Z' and an object '{', neither of which a reader
+                // accepts after '#'. Both have to stay plain objects.
+                json const j_null = json({{"_ArrayType_", "uint8"}, {"_ArraySize_", nullptr}, {"_ArrayData_", json::array()}});
+                const auto out_null = json::to_bjdata(j_null);
+                CHECK(out_null.at(0) == '{');
+                CHECK(json::from_bjdata(out_null) == j_null);
+
+                // an object shape passes the per-entry check by iterating its
+                // values rather than dimensions, so it needs rejecting too
+                json const j_obj = json({{"_ArrayType_", "uint8"}, {"_ArraySize_", {{"a", 1}}}, {"_ArrayData_", {1}}});
+                const auto out_obj = json::to_bjdata(j_obj);
+                CHECK(out_obj.at(0) == '{');
+                CHECK(json::from_bjdata(out_obj) == j_obj);
+
+                // a scalar shape is not a dimension list either
+                json const j_num = json({{"_ArrayType_", "uint8"}, {"_ArraySize_", 1}, {"_ArrayData_", {1}}});
+                const auto out_num = json::to_bjdata(j_num);
+                CHECK(out_num.at(0) == '{');
+                CHECK(json::from_bjdata(out_num) == j_num);
+            }
+
+            SECTION("ndarray with out-of-range _ArrayData_ elements stays as object")
+            {
+                // each element is cast to the (possibly narrower) C++ type
+                // named by _ArrayType_ before being written; a value that
+                // does not fit that type would silently wrap instead of
+                // being reported, so such an object falls back to a plain
+                // object encoding that still round-trips (see GitHub issue #5403)
+
+                // an unsigned element that does not fit uint8
+                json const j_uint8 = json({{"_ArrayType_", "uint8"}, {"_ArraySize_", {2}}, {"_ArrayData_", {1, 256}}});
+                const auto out_uint8 = json::to_bjdata(j_uint8);
+                CHECK(out_uint8.at(0) == '{');
+                CHECK(json::from_bjdata(out_uint8) == j_uint8);
+
+                // a signed element that does not fit int8
+                json const j_int8 = json({{"_ArrayType_", "int8"}, {"_ArraySize_", {2}}, {"_ArrayData_", {1, 200}}});
+                const auto out_int8 = json::to_bjdata(j_int8);
+                CHECK(out_int8.at(0) == '{');
+                CHECK(json::from_bjdata(out_int8) == j_int8);
+
+                // a negative element is likewise out of range for an
+                // unsigned _ArrayType_
+                json const j_uint16_neg = json({{"_ArrayType_", "uint16"}, {"_ArraySize_", {2}}, {"_ArrayData_", {1, -1}}});
+                const auto out_uint16_neg = json::to_bjdata(j_uint16_neg);
+                CHECK(out_uint16_neg.at(0) == '{');
+                CHECK(json::from_bjdata(out_uint16_neg) == j_uint16_neg);
+
+                // a double element that overflows to infinity when narrowed
+                // to the "single" (float) precision named by _ArrayType_
+                json const j_single = json({{"_ArrayType_", "single"}, {"_ArraySize_", {2}}, {"_ArrayData_", {1.5, 1e40}}});
+                const auto out_single = json::to_bjdata(j_single);
+                CHECK(out_single.at(0) == '{');
+                CHECK(json::from_bjdata(out_single) == j_single);
+
+                // in-range boundary values still use the compact ndarray encoding
+                json const j_uint8_ok = json({{"_ArrayType_", "uint8"}, {"_ArraySize_", {2}}, {"_ArrayData_", {0, 255}}});
+                CHECK(json::to_bjdata(j_uint8_ok) == std::vector<uint8_t>({'[', '$', 'U', '#', '[', 'i', 2, ']', 0, 255}));
+
+                json const j_int8_ok = json({{"_ArrayType_", "int8"}, {"_ArraySize_", {2}}, {"_ArrayData_", {-128, 127}}});
+                CHECK(json::to_bjdata(j_int8_ok) == std::vector<uint8_t>({'[', '$', 'i', '#', '[', 'i', 2, ']', 0x80, 0x7F}));
+
+                json const j_single_ok = json({{"_ArrayType_", "single"}, {"_ArraySize_", {1}}, {"_ArrayData_", {1.5}}});
+                const auto out_single_ok = json::to_bjdata(j_single_ok);
+                CHECK(out_single_ok.at(0) == '[');
+                CHECK(json::from_bjdata(out_single_ok) == json({1.5f}));
+            }
+
+            SECTION("ndarray with _ArrayType_ \"byte\" is gated by the BJData draft version")
+            {
+                // the 'B' (byte) marker used by _ArrayType_ "byte" is only defined
+                // by BJData Draft 3; Draft 2 (the default) has no such marker, so
+                // emitting it unconditionally produced a stream that a Draft 2
+                // reader could not parse as intended (see GitHub issue #5404).
+                // Two dimensions are used so that a successfully written ndarray
+                // round-trips back into the annotated object (a single dimension
+                // is, by the BJData ndarray convention, read back as a plain
+                // binary value rather than the annotated object, same as every
+                // other single-dimension ndarray of a non-"byte" type is read
+                // back as a plain array instead of the annotated object).
+                json const j_byte = json({{"_ArrayType_", "byte"}, {"_ArraySize_", {2, 3}}, {"_ArrayData_", {1, 2, 3, 4, 5, 6}}});
+
+                // default (Draft 2): falls back to a plain object and round-trips
+                const auto out_draft2 = json::to_bjdata(j_byte);
+                CHECK(out_draft2.at(0) == '{');
+                CHECK(json::from_bjdata(out_draft2) == j_byte);
+
+                // explicit Draft 2: same as the default
+                const auto out_draft2_explicit = json::to_bjdata(j_byte, true, true, json::bjdata_version_t::draft2);
+                CHECK(out_draft2_explicit.at(0) == '{');
+                CHECK(json::from_bjdata(out_draft2_explicit) == j_byte);
+
+                // Draft 3 explicitly selected: still uses the compact 'B' ndarray encoding
+                const auto out_draft3 = json::to_bjdata(j_byte, true, true, json::bjdata_version_t::draft3);
+                CHECK(out_draft3 == std::vector<uint8_t>({'[', '$', 'B', '#', '[', '$', 'i', '#', 'i', 2, 2, 3, 1, 2, 3, 4, 5, 6}));
+                CHECK(json::from_bjdata(out_draft3) == j_byte);
+            }
        }
    }

@@ -38,6 +38,54 @@ class huge_binary_t : public std::vector<std::uint8_t>
 using huge_binary_json = nlohmann::basic_json <
                         std::map, std::vector, std::string, bool, std::int64_t, std::uint64_t,
                         double, std::allocator, nlohmann::adl_serializer, huge_binary_t, void >;
+
+// a string type that can be made to report a size beyond INT32_MAX without
+// allocating that much memory, so BSON length overflow can be tested for
+// strings and (embedded) documents as well, following the same idea as
+// huge_binary_t.
+//
+// Unlike huge_binary_t (which is only ever used as the BSON *value* type),
+// this type doubles as basic_json's StringType and is therefore also used
+// for *object keys* (e.g. "s" or "nested" below). Only the designated test
+// value is meant to lie about its size - if every huge_string_t (including
+// keys) reported a huge size, the running totals computed while walking the
+// BSON document (see calc_bson_object_size & friends in binary_writer.hpp)
+// would need more than 32 bits, and on platforms where std::size_t is only
+// 32 bits wide that arithmetic would silently wrap around, producing wrong
+// (or even unguarded) lengths. The fake size is therefore opt-in via
+// as_huge(), and plain strings - in particular object keys - keep reporting
+// their real, small size.
+class huge_string_t : public std::string
+{
+  public:
+    using std::string::string;
+    huge_string_t(const std::string& s) : std::string(s) {} // NOLINT(google-explicit-constructor,hicpp-explicit-conversions)
+
+    // returns a copy of @a s whose size() pretends to be huge
+    static huge_string_t as_huge(const std::string& s)
+    {
+        huge_string_t result(s);
+        result.pretend_huge = true;
+        return result;
+    }
+
+    size_type size() const noexcept
+    {
+        if (pretend_huge)
+        {
+            // one byte more than the BSON length field can represent
+            return static_cast<size_type>((std::numeric_limits<std::int32_t>::max)()) + 1;
+        }
+        return std::string::size();
+    }
+
+  private:
+    bool pretend_huge = false;
+};
+
+using huge_string_json = nlohmann::basic_json <
+                         std::map, std::vector, huge_string_t, bool, std::int64_t, std::uint64_t,
+                         double, std::allocator, nlohmann::adl_serializer, std::vector<std::uint8_t>, void >;
 } // namespace

 TEST_CASE("BSON")
@@ -105,10 +153,36 @@ TEST_CASE("BSON")

    SECTION("lengths exceeding INT32_MAX cannot be serialized to BSON")
    {
-        huge_binary_json j;
-        j["b"] = huge_binary_json::binary(huge_binary_t{});
+        // out_of_range.412 is thrown from a single shared helper
+        // (to_bson_length) that guards the BSON length fields of binary
+        // values, strings, and (embedded) documents alike
+        SECTION("binary")
+        {
+            huge_binary_json j;
+            j["b"] = huge_binary_json::binary(huge_binary_t{});

-        CHECK_THROWS_WITH_AS(huge_binary_json::to_bson(j), "[json.exception.out_of_range.412] BSON length 2147483661 exceeds maximum of 2147483647", huge_binary_json::out_of_range&);
+            CHECK_THROWS_WITH_AS(huge_binary_json::to_bson(j), "[json.exception.out_of_range.412] BSON length 2147483661 exceeds maximum of 2147483647", huge_binary_json::out_of_range&);
+        }
+
+        SECTION("string")
+        {
+            huge_string_json j;
+            j["s"] = huge_string_t::as_huge("value");
+
+            CHECK_THROWS_WITH_AS(huge_string_json::to_bson(j), "[json.exception.out_of_range.412] BSON length 2147483661 exceeds maximum of 2147483647", huge_string_json::out_of_range&);
+        }
+
+        SECTION("document")
+        {
+            // an oversized string nested one level deep makes the
+            // *embedded* document's own length exceed INT32_MAX as well
+            huge_string_json nested;
+            nested["s"] = huge_string_t::as_huge("value");
+            huge_string_json j;
+            j["nested"] = nested;
+
+            CHECK_THROWS_WITH_AS(huge_string_json::to_bson(j), "[json.exception.out_of_range.412] BSON length 2147483674 exceeds maximum of 2147483647", huge_string_json::out_of_range&);
+        }
    }

    SECTION("string length must be at least 1")
@@ -193,6 +267,23 @@ TEST_CASE("BSON")
            CHECK(json::from_bson(result, true, false) == j);
        }

+        SECTION("non-empty object with bool from a non-0/1 byte (lenient parsing)")
+        {
+            // documented lenient behavior (see gh-5333): any non-zero byte
+            // is accepted as `true`, not just 0x01
+            std::vector<std::uint8_t> const input =
+            {
+                0x0D, 0x00, 0x00, 0x00, // size (little endian)
+                0x08,               // entry: boolean
+                'e', 'n', 't', 'r', 'y', '\x00',
+                0x02,           // value = 0x02 (neither 0x00 nor 0x01)
+                0x00                    // end marker
+            };
+
+            const json expected = { { "entry", true } };
+            CHECK(json::from_bson(input) == expected);
+        }
+
        SECTION("non-empty object with double")
        {
            json const j =
@@ -499,6 +590,29 @@ TEST_CASE("BSON")
            CHECK(json::from_bson(result, true, false) == j);
        }

+        SECTION("array elements with non-conforming keys (lenient parsing)")
+        {
+            // documented lenient behavior (see gh-5333): BSON array element
+            // keys are not checked against the required decimal sequence
+            // "0", "1", "2", ... - elements are taken in encoded order
+            std::vector<std::uint8_t> const input =
+            {
+                0x26, 0x00, 0x00, 0x00, // size (little endian)
+                0x04, 'e', 'n', 't', 'r', 'y', '\x00', // entry: embedded array
+
+                0x1A, 0x00, 0x00, 0x00, // size (little endian)
+                0x10, '5', 0x00, 0x0A, 0x00, 0x00, 0x00, // key "5" (bogus)      -> 10
+                0x10, 'x', 0x00, 0x14, 0x00, 0x00, 0x00, // key "x" (non-numeric) -> 20
+                0x10, '1', 0x00, 0x1E, 0x00, 0x00, 0x00, // key "1" (out of order) -> 30
+                0x00, // end marker (embedded array)
+
+                0x00 // end marker
+            };
+
+            const json expected = { { "entry", json::array({10, 20, 30}) } };
+            CHECK(json::from_bson(input) == expected);
+        }
+
        SECTION("non-empty object with binary member")
        {
            const size_t N = 10;
@@ -594,6 +708,31 @@ TEST_CASE("BSON")
            CHECK(json::from_bson(result, true, false) == j);
        }

+        SECTION("binary member with subtype 0x02 (old binary) keeps its inner length prefix (lenient parsing)")
+        {
+            // documented lenient behavior (see gh-5333): the payload for
+            // binary subtype 0x02 ("old binary") is returned as-is,
+            // including its own inner 4-byte length prefix; it is not
+            // stripped or reinterpreted
+            std::vector<std::uint8_t> const input =
+            {
+                0x17, 0x00, 0x00, 0x00, // size (little endian)
+                0x05, 'e', 'n', 't', 'r', 'y', '\x00', // entry: binary
+
+                0x06, 0x00, 0x00, 0x00, // size of binary (little endian)
+                0x02, // "old binary" subtype
+                0x02, 0x00, 0x00, 0x00, // inner length prefix (part of the old-binary payload)
+                0x68, 0x69, // payload ('h', 'i')
+
+                0x00 // end marker
+            };
+
+            // the inner length prefix is part of the (unmodified) payload
+            const std::vector<std::uint8_t> expected_payload = {0x02, 0x00, 0x00, 0x00, 0x68, 0x69};
+            const json expected = { { "entry", json::binary(expected_payload, 0x02) } };
+            CHECK(json::from_bson(input) == expected);
+        }
+
        SECTION("Some more complex document")
        {
            json const j =
@@ -23,6 +23,8 @@ using nlohmann::json;
 #include <utility>
 #include <vector>

+#include "test_utils.hpp"
+
 namespace
 {
 class SaxEventLogger
@@ -624,7 +626,8 @@ TEST_CASE("parser class")
            SECTION("overflow")
            {
                // overflows during parsing yield an exception
-                CHECK_THROWS_WITH_AS(parser_helper("1.18973e+4932").empty(), "[json.exception.out_of_range.406] number overflow parsing '1.18973e+4932'", json::out_of_range&);
+                // empty() is nodiscard; the exception is thrown by parser_helper() itself, before empty() would run
+                CHECK_THROWS_WITH_AS(utils::ignore_return_value(parser_helper("1.18973e+4932").empty()), "[json.exception.out_of_range.406] number overflow parsing '1.18973e+4932'", json::out_of_range&);
            }

            SECTION("invalid numbers")
@@ -930,6 +933,98 @@ TEST_CASE("parser class")
                CHECK(accept_helper("+1") == false);
                CHECK(accept_helper("+0") == false);
            }
+
+            SECTION("issue #5411 - skip conversion when accept() does not need the numeric value")
+            {
+                // lexer::scan_number() may skip strtoull()/strtoll() for
+                // value_unsigned/value_integer tokens when the caller (e.g.
+                // json::accept()) does not need the converted value, as long
+                // as the digit count alone guarantees no 64-bit overflow (see
+                // the "safe_digit_count" fast path in scan_number()). This
+                // differential test checks that json::accept() (which enables
+                // the fast path) and json::parse() (which never does) always
+                // agree, over a corpus that exercises both the fast path
+                // (<=18 digits) and the untouched, exact fallback path (>=19
+                // digits) -- including reclassification of huge digit-only
+                // integers to a (possibly non-finite) floating-point value.
+                const std::vector<std::pair<std::string, bool>> cases =
+                {
+                    // normal small/large integers, both signs
+                    {"0", true}, {"1", true}, {"-1", true}, {"42", true}, {"-42", true},
+                    {"123456789", true}, {"-123456789", true},
+
+                    // digit-count boundary around the 18-digit safe cutoff (both signs)
+                    {std::string(17, '9'), true},
+                    {std::string(18, '9'), true},
+                    {std::string(19, '9'), true},
+                    {std::string(20, '9'), true},
+                    {"-" + std::string(17, '9'), true},
+                    {"-" + std::string(18, '9'), true},
+                    {"-" + std::string(19, '9'), true},
+                    {"-" + std::string(20, '9'), true},
+
+                    // 64-bit boundaries
+                    {"9223372036854775807", true},    // INT64_MAX
+                    {"-9223372036854775808", true},   // INT64_MIN
+                    {"18446744073709551615", true},   // UINT64_MAX
+                    {"18446744073709551616", true},   // UINT64_MAX + 1 (overflows uint64_t, finite double)
+
+                    // the 28-digit example from the issue: overflows uint64_t
+                    // but is finite as a double, so the scanner reclassifies
+                    // it to value_float and it is accepted
+                    {"9999999999999999999999999999", true},
+
+                    // huge digit-only integers that overflow even a double -> rejected
+                    {std::string(309, '9'), false},
+                    {std::string(400, '9'), false},
+                    {"1" + std::string(400, '0'), false},
+
+                    // 1e999 / 1e400 style overflow -> rejected
+                    {"1e999", false},
+                    {"1e400", false},
+                    {"-1e999", false},
+                    {"1E999", false},
+
+                    // values straddling DBL_MAX
+                    {"1.7976931348623157e308", true},   // <= DBL_MAX, finite
+                    {"1.7976931348623159e308", false},  // > DBL_MAX, overflows to inf
+
+                    // a mix of other valid/invalid numeric syntax
+                    {"3.14159", true},
+                    {"-0.0", true},
+                    {"1.0e10", true},
+                    {"01", false},
+                    {"-", false},
+                    {"1.", false},
+                    {"1e", false},
+                    {"+1", false},
+                };
+
+                for (const auto& c : cases)
+                {
+                    const std::string& number = c.first;
+                    const bool expected = c.second;
+                    CAPTURE(number)
+                    CAPTURE(expected)
+
+                    // accept() takes the fast path (skips conversion when possible)
+                    CHECK(json::accept(number) == expected);
+
+                    // parse() always performs the full conversion; it must agree
+                    json j;
+                    CHECK_NOTHROW(json::parser(nlohmann::detail::input_adapter(number), nullptr, false).parse(true, j));
+                    CHECK(!j.is_discarded() == expected);
+
+                    // wrap in an array so get_token() is exercised beyond the
+                    // very first (constructor-time) scan as well
+                    std::string wrapped = "[";
+                    wrapped += number;
+                    wrapped += ",";
+                    wrapped += number;
+                    wrapped += "]";
+                    CHECK(json::accept(wrapped) == expected);
+                }
+            }
        }
    }

@@ -1394,6 +1489,71 @@ TEST_CASE("parser class")
        CHECK(accept_helper("\"\\uD80C\\uFFFF\"") == false);
    }

+#if !defined(JSON_NOEXCEPTION)
+    SECTION("issue #5412 - whitespace skipping bookkeeping (compact vs. pretty-printed)")
+    {
+        // lexer::skip_whitespace() reads its first character with get() (to
+        // honor a possibly pending unget() from the previous token) and every
+        // further whitespace character with get_ignoring_pending_unget() (a
+        // get() variant that skips the then-always-false next_unget check).
+        // This must not change the reported byte offset, line, or column of
+        // a syntax error, even when a long run of whitespace containing
+        // multiple newlines is skipped beforehand (as with pretty-printed
+        // input). The expected values below were captured from the
+        // unmodified do-while(get()) loop, so any regression that miscounts
+        // characters or newlines while skipping whitespace changes them.
+        const auto check_error = [](const std::string & input, std::size_t expected_byte,
+                                    const std::string & expected_what)
+        {
+            CAPTURE(input)
+            try
+            {
+                json _ = json::parse(input);
+                FAIL_CHECK("expected a parse_error, but parsing succeeded");
+            }
+            catch (const json::parse_error& e)
+            {
+                CHECK(e.byte == expected_byte);
+                CHECK(std::string(e.what()) == expected_what);
+            }
+        };
+
+        // a nested document, serialized both compactly and pretty-printed
+        // (dump(4)), each truncated right before the final closing '}' so
+        // that the parser hits EOF after skipping all of the (in the
+        // pretty-printed case, substantial) indentation whitespace
+        const json doc =
+        {
+            {"a", 1},
+            {"b", json::array({true, false, nullptr, "x"})},
+            {"c", json::object({{"d", 3.14}, {"e", json::array({1, 2, 3})}})}
+        };
+
+        const std::string compact = doc.dump();
+        const std::string pretty = doc.dump(4);
+
+        check_error(compact.substr(0, compact.size() - 1), 60,
+                    "[json.exception.parse_error.101] parse error at line 1, column 60: syntax error while parsing object - unexpected end of input; expected '}'");
+        check_error(pretty.substr(0, pretty.size() - 1), 193,
+                    "[json.exception.parse_error.101] parse error at line 17, column 1: syntax error while parsing object - unexpected end of input; expected '}'");
+
+        // an invalid token appearing after several indented, multi-line
+        // whitespace runs vs. the same document without any of that
+        // whitespace
+        check_error(R"({
+    "a": 1,
+    "b": [
+        true,
+        false
+    ],
+    "c": @
+})", 70,
+                    "[json.exception.parse_error.101] parse error at line 7, column 10: syntax error while parsing value - invalid literal; last read: '\"c\": @'");
+        check_error(R"({"a":1,"b":[true,false],"c":@})", 29,
+                    "[json.exception.parse_error.101] parse error at line 1, column 29: syntax error while parsing value - invalid literal; last read: '\"c\":@'");
+    }
+#endif
+
    SECTION("tests found by mutate++")
    {
        // test case to make sure no comma precedes the first key
@@ -22,6 +22,8 @@ using nlohmann::json;

 #include <valarray>

+#include "test_utils.hpp"
+
 namespace
 {
 class SaxEventLogger
@@ -629,7 +631,8 @@ TEST_CASE("parser class")
            SECTION("overflow")
            {
                // overflows during parsing yield an exception
-                CHECK_THROWS_WITH_AS(parser_helper("1.18973e+4932").empty(), "[json.exception.out_of_range.406] number overflow parsing '1.18973e+4932'", json::out_of_range&);
+                // empty() is nodiscard; the exception is thrown by parser_helper() itself, before empty() would run
+                CHECK_THROWS_WITH_AS(utils::ignore_return_value(parser_helper("1.18973e+4932").empty()), "[json.exception.out_of_range.406] number overflow parsing '1.18973e+4932'", json::out_of_range&);
            }

            SECTION("invalid numbers")
@@ -326,6 +326,57 @@ TEST_CASE("lexicographical comparison operators")
 #endif
        }

+        SECTION("integer/float mixed comparison is exact")
+        {
+            // Widening the integer to a double loses precision past the
+            // mantissa, so 2^63-2 and 2^63-1 both used to compare equal to the
+            // double 2^63 while differing from each other. That makes equality
+            // intransitive and the ordering not a strict weak ordering.
+            const json below_two_63 = static_cast<std::int64_t>(9223372036854775806LL);
+            const json max_int64 = (std::numeric_limits<std::int64_t>::max)();
+            const json two_63 = 9223372036854775808.0;
+
+            CHECK_FALSE(below_two_63 == two_63);
+            CHECK_FALSE(max_int64 == two_63);
+            CHECK(below_two_63 != max_int64);
+            CHECK(below_two_63 < max_int64);
+            CHECK(below_two_63 < two_63);
+            CHECK(max_int64 < two_63);
+            CHECK(two_63 > max_int64);
+            CHECK_FALSE(two_63 < max_int64);
+
+            // the same past the unsigned range
+            const json max_uint64 = (std::numeric_limits<std::uint64_t>::max)();
+            const json two_64 = 18446744073709551616.0;
+            CHECK_FALSE(max_uint64 == two_64);
+            CHECK(max_uint64 < two_64);
+            CHECK(two_64 > max_uint64);
+
+            // values a double represents exactly still compare equal
+            CHECK(json(1) == json(1.0));
+            CHECK(json(1u) == json(1.0));
+            CHECK(json(-3) == json(-3.0));
+            CHECK(json(1) < json(1.5));
+            CHECK(json(1.5) < json(2));
+            CHECK(json(2) > json(1.5));
+
+            // a NaN operand stays unordered against either integer kind
+            CHECK_FALSE(json(1) == json(nan));
+            CHECK_FALSE(json(1) < json(nan));
+            CHECK_FALSE(json(nan) < json(1));
+            CHECK_FALSE(json(1u) == json(nan));
+
+#if JSON_HAS_THREE_WAY_COMPARISON
+            // JSON_HAS_CPP_20 (do not remove; see note at top of file)
+            CHECK((max_int64 <=> two_63) == std::partial_ordering::less); // *NOPAD*
+            CHECK((two_63 <=> max_int64) == std::partial_ordering::greater); // *NOPAD*
+            CHECK((below_two_63 <=> max_int64) == std::partial_ordering::less); // *NOPAD*
+            CHECK((max_uint64 <=> two_64) == std::partial_ordering::less); // *NOPAD*
+            CHECK((json(1) <=> json(1.0)) == std::partial_ordering::equivalent); // *NOPAD*
+            CHECK((json(1) <=> json(nan)) == std::partial_ordering::unordered); // *NOPAD*
+#endif
+        }
+
        SECTION("compares unordered")
        {
            std::vector<std::vector<bool>> expected =
@@ -1389,6 +1389,37 @@ TEST_CASE("value conversion")
                // CHECK(m5["one"] == "eins");
            }

+            SECTION("reserve is called on containers that support it (#5406)")
+            {
+                // build a larger object so that a missing/incorrect reserve()
+                // call would be more likely to corrupt or drop elements
+                json j_large;
+                for (int i = 0; i < 100; ++i)
+                {
+                    j_large[std::to_string(i)] = i;
+                }
+
+                SECTION("std::unordered_map (supports reserve)")
+                {
+                    const auto m = j_large.get<std::unordered_map<std::string, int>>();
+                    CHECK(m.size() == 100);
+                    for (int i = 0; i < 100; ++i)
+                    {
+                        CHECK(m.at(std::to_string(i)) == i);
+                    }
+                }
+
+                SECTION("std::map (no reserve, fallback path)")
+                {
+                    const auto m = j_large.get<std::map<std::string, int>>();
+                    CHECK(m.size() == 100);
+                    for (int i = 0; i < 100; ++i)
+                    {
+                        CHECK(m.at(std::to_string(i)) == i);
+                    }
+                }
+            }
+
            SECTION("std::multimap")
            {
                j1.get<std::multimap<std::string, int>>();
@@ -1,150 +0,0 @@
-//     __ _____ _____ _____
-//  __|  |   __|     |   | |  JSON for Modern C++ (supporting code)
-// |  |  |__   |  |  | | | |  version 3.12.0
-// |_____|_____|_____|_|___|  https://github.com/nlohmann/json
-//
-// SPDX-FileCopyrightText: 2013-2026 Niels Lohmann <https://nlohmann.me>
-// SPDX-License-Identifier: MIT
-
-#include "doctest_compatibility.h"
-
-#include <nlohmann/json.hpp>
-
-#include <deque>
-#include <map>
-#include <memory>
-#include <string>
-#include <type_traits>
-#include <vector>
-
-namespace
-{
-
-// std::deque has no capacity() member function, which the library only needs
-// to detect a reallocation for JSON_DIAGNOSTICS
-using deque_json = nlohmann::basic_json<std::map, std::deque>;
-
-// a std::vector whose at() is hidden: the library performs its own bounds
-// check and must not fall back to the container's checked accessor
-template<class T, class Allocator = std::allocator<T>>
-class vector_without_at : public std::vector<T, Allocator>
-{
-  public:
-    vector_without_at() = default;
-
-    // the array of an initializer list is built from a range
-    template<class InputIt>
-    vector_without_at(InputIt first, InputIt last) : std::vector<T, Allocator>(first, last) {}
-
-    void at() = delete;
-};
-
-using no_at_json = nlohmann::basic_json<std::map, vector_without_at>;
-
-} // namespace
-
-TEST_CASE("array type without capacity()")
-{
-    SECTION("the iterators take their exception specification from the container")
-    {
-        // basic_json's iterators move exactly as the container iterators do:
-        // their move operations are defaulted without a declared noexcept,
-        // because an array or object type whose iterator is not nothrow move
-        // constructible would otherwise have them deleted (std::deque's is not
-        // with libstdc++ before 11, and neither are MSVC's debug iterators)
-        CHECK(std::is_nothrow_move_constructible<nlohmann::json::iterator>::value ==
-              (std::is_nothrow_move_constructible<nlohmann::json::object_t::iterator>::value
-               && std::is_nothrow_move_constructible<nlohmann::json::array_t::iterator>::value));
-        CHECK(std::is_nothrow_move_assignable<nlohmann::json::iterator>::value ==
-              (std::is_nothrow_move_assignable<nlohmann::json::object_t::iterator>::value
-               && std::is_nothrow_move_assignable<nlohmann::json::array_t::iterator>::value));
-        CHECK(std::is_nothrow_move_constructible<nlohmann::json::const_iterator>::value ==
-              (std::is_nothrow_move_constructible<nlohmann::json::object_t::const_iterator>::value
-               && std::is_nothrow_move_constructible<nlohmann::json::array_t::const_iterator>::value));
-
-        // and they are movable at all, which is what dropping the declared
-        // noexcept buys for a std::deque array
-        CHECK(std::is_move_constructible<deque_json::iterator>::value);
-        CHECK(std::is_move_assignable<deque_json::iterator>::value);
-    }
-
-    SECTION("adding elements")
-    {
-        deque_json j = deque_json::array();
-        j.push_back(1);
-        j.push_back("two");
-        j.emplace_back(3);
-        j += 4;
-
-        CHECK(j.size() == 4);
-        CHECK(j == deque_json({1, "two", 3, 4}));
-        CHECK(j.back() == 4);
-        CHECK(j.front() == 1);
-    }
-
-    SECTION("accessing and modifying elements")
-    {
-        auto j = deque_json::parse(R"([1,2,3])");
-
-        CHECK(j[1] == 2);
-        CHECK(j.at(2) == 3);
-
-        // growing through operator[] fills up with null values
-        j[5] = 6;
-        CHECK(j.size() == 6);
-        CHECK(j[4].is_null());
-        CHECK(j[5] == 6);
-
-        j.erase(0);
-        CHECK(j == deque_json({2, 3, nullptr, nullptr, 6}));
-
-        auto it = j.erase(j.begin());
-        CHECK(*it == 3);
-
-        j.insert(j.begin(), 1);
-        CHECK(j.front() == 1);
-    }
-
-    SECTION("serialization and deserialization")
-    {
-        const auto j = deque_json::parse(R"({"a":[1,[2,3]],"b":[]})");
-        CHECK(j.dump() == R"({"a":[1,[2,3]],"b":[]})");
-        CHECK(deque_json::parse(j.dump()) == j);
-        CHECK(deque_json::from_cbor(deque_json::to_cbor(j)) == j);
-
-        // empty containers are flattened to null and cannot be restored
-        const auto nested = deque_json::parse(R"({"a":[1,[2,3]]})");
-        CHECK(nested.flatten().unflatten() == nested);
-    }
-
-    SECTION("references stay valid while the array grows")
-    {
-        deque_json j = deque_json::array();
-        j.push_back(1);
-        auto& first = j[0];
-        for (int i = 0; i < 100; ++i)
-        {
-            j.push_back(i);
-        }
-        CHECK(&first == &j[0]);
-        CHECK(first == 1);
-    }
-}
-
-TEST_CASE("array type without at()")
-{
-    // built in memory rather than parsed, so that the exception message does
-    // not gain a byte range with JSON_DIAGNOSTIC_POSITIONS
-    no_at_json j = {1, 2, 3};
-    const auto& jc = j;
-
-    CHECK(j.at(0) == 1);
-    CHECK(j.at(2) == 3);
-    CHECK(jc.at(2) == 3);
-
-    CHECK_THROWS_WITH_AS(j.at(3), "[json.exception.out_of_range.401] array index 3 is out of range", no_at_json::out_of_range);
-    CHECK_THROWS_WITH_AS(jc.at(3), "[json.exception.out_of_range.401] array index 3 is out of range", no_at_json::out_of_range);
-
-    CHECK(j.at(no_at_json::json_pointer("/1")) == 2);
-    CHECK_THROWS_AS(j.at(no_at_json::json_pointer("/3")), no_at_json::out_of_range);
-}
@@ -1,79 +0,0 @@
-//     __ _____ _____ _____
-//  __|  |   __|     |   | |  JSON for Modern C++ (supporting code)
-// |  |  |__   |  |  | | | |  version 3.12.0
-// |_____|_____|_____|_|___|  https://github.com/nlohmann/json
-//
-// SPDX-FileCopyrightText: 2013-2026 Niels Lohmann <https://nlohmann.me>
-// SPDX-License-Identifier: MIT
-
-#include "doctest_compatibility.h"
-
-#include <nlohmann/json.hpp>
-
-#include <cstdint>
-#include <functional>
-#include <map>
-#include <memory>
-#include <string>
-#include <vector>
-
-#ifdef JSON_HAS_CPP_17
-    #include <cstddef>
-#endif
-
-namespace
-{
-
-// a BinaryType whose value type is signed: the elements must still be
-// processed as the numbers 0..255
-using char_binary_json = nlohmann::basic_json <
-                         std::map, std::vector, std::string, bool, std::int64_t, std::uint64_t,
-                         double, std::allocator, nlohmann::adl_serializer, std::vector<char>, void >;
-
-#ifdef JSON_HAS_CPP_17
-    // a BinaryType whose value type is not an integer type at all
-    using byte_binary_json = nlohmann::basic_json <
-    std::map, std::vector, std::string, bool, std::int64_t, std::uint64_t,
-    double, std::allocator, nlohmann::adl_serializer, std::vector<std::byte>, void >;
-#endif
-
-} // namespace
-
-TEST_CASE("binary type whose value type is not std::uint8_t")
-{
-    SECTION("a signed value type does not dump negative numbers")
-    {
-        const std::vector<char> chars{'\0', '\x01', '\xFF'};
-        CHECK(char_binary_json::binary(chars).dump() == R"({"bytes":[0,1,255],"subtype":null})");
-        CHECK(char_binary_json::binary(chars, 42).dump() == R"({"bytes":[0,1,255],"subtype":42})");
-        CHECK(char_binary_json::binary({}).dump() == R"({"bytes":[],"subtype":null})");
-    }
-
-    SECTION("the default binary type is unchanged")
-    {
-        CHECK(nlohmann::json::binary({0, 1, 255}, 42).dump() == R"({"bytes":[0,1,255],"subtype":42})");
-    }
-
-#ifdef JSON_HAS_CPP_17
-    SECTION("dumping a value type that is not an integer")
-    {
-        const std::vector<std::byte> bytes{std::byte{0}, std::byte{1}, std::byte{0xFF}};
-        CHECK(byte_binary_json::binary(bytes).dump() == R"({"bytes":[0,1,255],"subtype":null})");
-        CHECK(byte_binary_json::binary(bytes, 42).dump() == R"({"bytes":[0,1,255],"subtype":42})");
-        CHECK(byte_binary_json::binary({}).dump() == R"({"bytes":[],"subtype":null})");
-    }
-
-    SECTION("hashing and the binary formats")
-    {
-        const std::vector<std::byte> bytes{std::byte{0}, std::byte{1}, std::byte{0xFF}};
-        const auto j = byte_binary_json::binary(bytes);
-
-        CHECK(std::hash<byte_binary_json> {}(j) == std::hash<byte_binary_json> {}(j));
-        CHECK(byte_binary_json::from_cbor(byte_binary_json::to_cbor(j)) == j);
-        CHECK(byte_binary_json::from_msgpack(byte_binary_json::to_msgpack(j)) == j);
-
-        // UBJSON has no binary type, so binary values are written as an array
-        CHECK(byte_binary_json::from_ubjson(byte_binary_json::to_ubjson(j)) == byte_binary_json({0, 1, 255}));
-    }
-#endif
-}
@@ -1,323 +0,0 @@
-//     __ _____ _____ _____
-//  __|  |   __|     |   | |  JSON for Modern C++ (supporting code)
-// |  |  |__   |  |  | | | |  version 3.12.0
-// |_____|_____|_____|_|___|  https://github.com/nlohmann/json
-//
-// SPDX-FileCopyrightText: 2013-2026 Niels Lohmann <https://nlohmann.me>
-// SPDX-License-Identifier: MIT
-
-#include "doctest_compatibility.h"
-
-#include <nlohmann/json.hpp>
-
-#include <cstdint>
-#include <map>
-#include <string>
-#include <type_traits>
-#include <utility>
-#include <vector>
-
-
-namespace
-{
-
-// An ObjectType that does *not* define a key_compare member type, which is
-// what every hash map looks like to the library.
-//
-// A hash map is deliberately not used here: object_t is probed for
-// key_compare inside the definition of basic_json, that is, while basic_json
-// is still an incomplete type, and whether a hash map can be instantiated
-// with an incomplete mapped type depends on the standard library (libstdc++ 9
-// needs the size of the mapped type for its node type and rejects it). So the
-// object type wraps a std::map instead of inheriting from it: an earlier
-// version derived from std::map and shadowed the inherited key_compare type
-// with a same-named member function, relying on ordinary member hiding to
-// make key_compare unreachable as a type. MSVC 2017 (AppVeyor, /std:c++17)
-// does not honor that hiding for a typename-qualified lookup performed from
-// outside the class and still resolves key_compare to the base's comparator
-// type, so the library's probe incorrectly found one. Composition sidesteps
-// the question entirely: with no base class, there is no key_compare to find
-// under any lookup rule.
-template<class Key, class T, class Compare, class Allocator>
-class no_key_compare_map
-{
-    using map_t = std::map<Key, T, Compare, Allocator>;
-    map_t data;
-
-  public:
-    using key_type = typename map_t::key_type;
-    using mapped_type = typename map_t::mapped_type;
-    using value_type = typename map_t::value_type;
-    using size_type = typename map_t::size_type;
-    using allocator_type = typename map_t::allocator_type;
-    using iterator = typename map_t::iterator;
-    using const_iterator = typename map_t::const_iterator;
-
-    // -Weffc++ asks for the member to be initialized in the member
-    // initialization list, which a defaulted constructor does not do; the
-    // exception specification a defaulted one would have carried has to be
-    // written out as well, or -Wnoexcept objects where the standard library
-    // takes noexcept(construct(...))
-    no_key_compare_map() noexcept(std::is_nothrow_default_constructible<map_t>::value) : data() {}
-
-    // converting between two basic_json types builds the object from a range
-    template<class InputIt>
-    no_key_compare_map(InputIt first, InputIt last) : data(first, last) {}
-
-    iterator begin() noexcept
-    {
-        return data.begin();
-    }
-    iterator end() noexcept
-    {
-        return data.end();
-    }
-    const_iterator begin() const noexcept
-    {
-        return data.begin();
-    }
-    const_iterator end() const noexcept
-    {
-        return data.end();
-    }
-    const_iterator cbegin() const noexcept
-    {
-        return data.cbegin();
-    }
-    const_iterator cend() const noexcept
-    {
-        return data.cend();
-    }
-
-    bool empty() const noexcept
-    {
-        return data.empty();
-    }
-    size_type size() const noexcept
-    {
-        return data.size();
-    }
-    size_type max_size() const noexcept
-    {
-        return data.max_size();
-    }
-    void clear() noexcept
-    {
-        data.clear();
-    }
-
-    iterator find(const key_type& key)
-    {
-        return data.find(key);
-    }
-    const_iterator find(const key_type& key) const
-    {
-        return data.find(key);
-    }
-    size_type count(const key_type& key) const
-    {
-        return data.count(key);
-    }
-
-    std::pair<iterator, bool> emplace(const key_type& key, const mapped_type& value)
-    {
-        return data.emplace(key, value);
-    }
-
-    std::pair<iterator, bool> insert(const value_type& value)
-    {
-        return data.insert(value);
-    }
-
-    template<class InputIt>
-    void insert(InputIt first, InputIt last)
-    {
-        data.insert(first, last);
-    }
-
-    mapped_type& operator[](const key_type& key)
-    {
-        return data[key];
-    }
-
-    mapped_type& at(const key_type& key)
-    {
-        return data.at(key);
-    }
-    const mapped_type& at(const key_type& key) const
-    {
-        return data.at(key);
-    }
-
-    iterator erase(iterator pos)
-    {
-        return data.erase(pos);
-    }
-    iterator erase(iterator first, iterator last)
-    {
-        return data.erase(first, last);
-    }
-    size_type erase(const key_type& key)
-    {
-        return data.erase(key);
-    }
-
-    void swap(no_key_compare_map& other) noexcept(noexcept(data.swap(other.data)))
-    {
-        data.swap(other.data);
-    }
-
-    friend bool operator==(const no_key_compare_map& lhs, const no_key_compare_map& rhs)
-    {
-        return lhs.data == rhs.data;
-    }
-    friend bool operator<(const no_key_compare_map& lhs, const no_key_compare_map& rhs)
-    {
-        return lhs.data < rhs.data;
-    }
-};
-
-using no_key_compare_json = nlohmann::basic_json<no_key_compare_map>;
-
-// An ObjectType whose erase(iterator) returns void rather than the following
-// iterator, as for instance Abseil's hash maps do
-template<class Key, class T, class Compare, class Allocator>
-struct void_erase_map : std::map<Key, T, Compare, Allocator>
-{
-    using base_t = std::map<Key, T, Compare, Allocator>;
-    using iterator = typename base_t::iterator;
-    using base_t::erase;
-
-    void erase(iterator pos)
-    {
-        base_t::erase(pos);
-    }
-};
-
-using void_erase_json = nlohmann::basic_json<void_erase_map>;
-
-} // namespace
-
-TEST_CASE("object type whose erase() returns void")
-{
-    SECTION("erasing every element through the returned iterator")
-    {
-        void_erase_json j;
-        for (int i = 0; i < 8; ++i)
-        {
-            j["k" + std::to_string(i)] = i;
-        }
-
-        std::size_t erased = 0;
-        for (auto it = j.begin(); it != j.end(); ++erased)
-        {
-            it = j.erase(it);
-        }
-        CHECK(erased == 8);
-        CHECK(j.empty());
-    }
-
-    SECTION("erasing in the middle returns the following element")
-    {
-        void_erase_json j;
-        for (int i = 0; i < 4; ++i)
-        {
-            j["k" + std::to_string(i)] = i;
-        }
-
-        auto it = j.begin();
-        ++it;
-        const auto after = j.erase(it);
-        CHECK(j.size() == 3);
-        CHECK(after.key() == "k2");
-        CHECK(after.value() == 2);
-        CHECK(!j.contains("k1"));
-    }
-
-    SECTION("the other erase overloads are unaffected")
-    {
-        void_erase_json j;
-        j["a"] = 1;
-        j["b"] = 2;
-        j["c"] = 3;
-
-        CHECK(j.erase("a") == 1);
-        CHECK(j.erase("nope") == 0);
-        j.erase(j.begin(), j.end());
-        CHECK(j.empty());
-    }
-}
-
-TEST_CASE("object type without key_compare")
-{
-    SECTION("object_comparator_t falls back to default_object_comparator_t")
-    {
-        CHECK(std::is_same < no_key_compare_json::object_comparator_t,
-              no_key_compare_json::default_object_comparator_t >::value);
-    }
-
-    SECTION("object types defining key_compare are unaffected")
-    {
-        CHECK(std::is_same<nlohmann::json::object_comparator_t,
-              nlohmann::json::object_t::key_compare>::value);
-        CHECK(std::is_same<nlohmann::ordered_json::object_comparator_t,
-              nlohmann::ordered_json::object_t::key_compare>::value);
-    }
-
-    SECTION("creating and accessing values")
-    {
-        no_key_compare_json j;
-        j["one"] = 1;
-        j["two"] = "zwei";
-        j["three"]["nested"] = true;
-
-        CHECK(j.size() == 3);
-        CHECK(j.at("one") == 1);
-        CHECK(j["two"] == "zwei");
-        CHECK(j["three"]["nested"] == true);
-        CHECK(j.contains("one"));
-        CHECK(!j.contains("four"));
-        CHECK(j.find("one") != j.end());
-        CHECK(j.count("one") == 1);
-        CHECK(j.erase("one") == 1);
-        CHECK(j.size() == 2);
-    }
-
-    SECTION("serialization and deserialization")
-    {
-        const auto j = no_key_compare_json::parse(R"({"a":[1,2,3],"b":{"c":null}})");
-        CHECK(j["a"].size() == 3);
-        CHECK(j["a"][2] == 3);
-        CHECK(j["b"]["c"].is_null());
-        CHECK(no_key_compare_json::parse(j.dump()) == j);
-    }
-
-    SECTION("binary formats")
-    {
-        const auto j = no_key_compare_json::parse(R"({"a":[1,2,3],"b":"x"})");
-        CHECK(no_key_compare_json::from_cbor(no_key_compare_json::to_cbor(j)) == j);
-        CHECK(no_key_compare_json::from_msgpack(no_key_compare_json::to_msgpack(j)) == j);
-    }
-
-    SECTION("flatten and unflatten")
-    {
-        // "o" has a key that looks like an array index, so unflatten() must
-        // not turn it into an array
-        const auto j = no_key_compare_json::parse(
-                           R"({"c":[1,2,3],"d":{"e":"s"},"n":[[0,1],[2]],"o":{"2":"x"}})");
-        CHECK(j.flatten().unflatten() == j);
-    }
-
-    SECTION("conversion to and from nlohmann::json")
-    {
-        const auto j = no_key_compare_json::parse(R"({"a":1,"b":[true,null]})");
-        const nlohmann::json converted(j);
-
-        CHECK(converted.is_object());
-        CHECK(converted["a"] == 1);
-        CHECK(converted["b"][0] == true);
-        CHECK(converted["b"][1].is_null());
-        CHECK(no_key_compare_json(converted) == j);
-    }
-}
-
@@ -0,0 +1,42 @@
+//     __ _____ _____ _____
+//  __|  |   __|     |   | |  JSON for Modern C++ (supporting code)
+// |  |  |__   |  |  | | | |  version 3.12.0
+// |_____|_____|_____|_|___|  https://github.com/nlohmann/json
+//
+// SPDX-FileCopyrightText: 2013-2026 Niels Lohmann <https://nlohmann.me>
+// SPDX-License-Identifier: MIT
+
+// This file contains the C++17-only part of unit-items.cpp (structured
+// bindings support for json::items()). It is kept in a separate
+// translation unit so the (much larger) unit-items.cpp does not need to
+// be compiled a second time just for this one SECTION.
+
+#include "doctest_compatibility.h"
+
+#include <nlohmann/json.hpp>
+using nlohmann::json;
+
+#ifdef JSON_HAS_CPP_17
+#include <map>
+#include <string>
+
+TEST_CASE("items()")
+{
+    SECTION("object")
+    {
+        SECTION("structured bindings")
+        {
+            json j = { {"A", 1}, {"B", 2} };
+
+            std::map<std::string, int> m;
+
+            for (auto const&[key, value] : j.items())
+            {
+                m.emplace(key, value);
+            }
+
+            CHECK(j.get<decltype(m)>() == m);
+        }
+    }
+}
+#endif
@@ -862,22 +862,6 @@ TEST_CASE("items()")

            CHECK(counter == 3);
        }
-
-#ifdef JSON_HAS_CPP_17
-        SECTION("structured bindings")
-        {
-            json j = { {"A", 1}, {"B", 2} };
-
-            std::map<std::string, int> m;
-
-            for (auto const&[key, value] : j.items())
-            {
-                m.emplace(key, value);
-            }
-
-            CHECK(j.get<decltype(m)>() == m);
-        }
-#endif
    }

    SECTION("const object")
@@ -1388,3 +1388,270 @@ TEST_CASE("JSON patch - add to a primitive parent (regression #4292)")
        CHECK_THROWS_AS(doc.patch(patch), json::out_of_range&);
    }
 }
+
+TEST_CASE("JSON patch - remove with primitive or null parent (regression #5396)")
+{
+    // Regression test for https://github.com/nlohmann/json/issues/5396
+    //
+    // RFC 6902 (§4.2) requires the target location of a "remove" operation
+    // to exist. When the target's parent resolves to a primitive value or
+    // null, the operation must fail. Previously operation_remove silently
+    // did nothing in this case (neither the "is_object" nor the "is_array"
+    // branch matched, and there was no final "else"), so the patch appeared
+    // to succeed without changing the document. It now throws
+    // out_of_range.413.
+
+    SECTION("parent is a primitive (number)")
+    {
+        json const doc = {{"a", 1}};
+        json const patch = {{{"op", "remove"}, {"path", "/a/b"}}};
+#if JSON_DIAGNOSTICS
+        CHECK_THROWS_WITH_AS(doc.patch(patch), "[json.exception.out_of_range.413] (/a) cannot remove value: the JSON Patch 'remove' target's parent is of type number, but must be an object or array", json::out_of_range&);
+#else
+        CHECK_THROWS_WITH_AS(doc.patch(patch), "[json.exception.out_of_range.413] cannot remove value: the JSON Patch 'remove' target's parent is of type number, but must be an object or array", json::out_of_range&);
+#endif
+    }
+
+    SECTION("parent is a primitive (string)")
+    {
+        json const doc = {{"foo", {{"bar", "a string"}}}};
+        json const patch = {{{"op", "remove"}, {"path", "/foo/bar/baz"}}};
+#if JSON_DIAGNOSTICS
+        CHECK_THROWS_WITH_AS(doc.patch(patch), "[json.exception.out_of_range.413] (/foo/bar) cannot remove value: the JSON Patch 'remove' target's parent is of type string, but must be an object or array", json::out_of_range&);
+#else
+        CHECK_THROWS_WITH_AS(doc.patch(patch), "[json.exception.out_of_range.413] cannot remove value: the JSON Patch 'remove' target's parent is of type string, but must be an object or array", json::out_of_range&);
+#endif
+    }
+
+    SECTION("top-level document is null")
+    {
+        json const doc = nullptr;
+        json const patch = {{{"op", "remove"}, {"path", "/a"}}};
+        CHECK_THROWS_WITH_AS(doc.patch(patch), "[json.exception.out_of_range.413] cannot remove value: the JSON Patch 'remove' target's parent is of type null, but must be an object or array", json::out_of_range&);
+    }
+
+    SECTION("legitimate removes still work")
+    {
+        // object member
+        json const doc1 = {{"a", 1}, {"b", 2}};
+        json const patch1 = {{{"op", "remove"}, {"path", "/a"}}};
+        CHECK(doc1.patch(patch1) == json({{"b", 2}}));
+
+        // array element
+        json const doc2 = R"([1, 2, 3])"_json;
+        json const patch2 = {{{"op", "remove"}, {"path", "/1"}}};
+        CHECK(doc2.patch(patch2) == R"([1, 3])"_json);
+    }
+}
+
+TEST_CASE("JSON patch - move where 'from' is a proper prefix of 'path' (regression #5397)")
+{
+    // Regression test for https://github.com/nlohmann/json/issues/5397
+    //
+    // RFC 6902 (§4.4) forbids "from" from being a proper prefix of "path"
+    // for a "move" operation: "a location cannot be moved into one of its
+    // children." "move" is implemented as remove-then-add; for an object
+    // target this happened to throw anyway as a side effect of the "add"
+    // step re-resolving through the now-removed parent, but for an array
+    // target the removal shifted subsequent indices, so "path" silently
+    // re-resolved to a different element and the operation "succeeded"
+    // with a corrupted result. It now throws out_of_range.414 for both
+    // object and array targets.
+
+    SECTION("array target (from the issue)")
+    {
+        json const doc = R"([[1,2],[3]])"_json;
+        json const patch = {{{"op", "move"}, {"from", "/0"}, {"path", "/0/0"}}};
+#if JSON_DIAGNOSTIC_POSITIONS
+        CHECK_THROWS_WITH_AS(doc.patch(patch), "[json.exception.out_of_range.414] (bytes 0-11) cannot move value: 'from' path '/0' is a proper prefix of 'path' '/0/0'", json::out_of_range&);
+#else
+        CHECK_THROWS_WITH_AS(doc.patch(patch), "[json.exception.out_of_range.414] cannot move value: 'from' path '/0' is a proper prefix of 'path' '/0/0'", json::out_of_range&);
+#endif
+    }
+
+    SECTION("object target")
+    {
+        json const doc = R"({"a": {"b": 1}})"_json;
+        json const patch = {{{"op", "move"}, {"from", "/a"}, {"path", "/a/b"}}};
+#if JSON_DIAGNOSTIC_POSITIONS
+        CHECK_THROWS_WITH_AS(doc.patch(patch), "[json.exception.out_of_range.414] (bytes 0-15) cannot move value: 'from' path '/a' is a proper prefix of 'path' '/a/b'", json::out_of_range&);
+#else
+        CHECK_THROWS_WITH_AS(doc.patch(patch), "[json.exception.out_of_range.414] cannot move value: 'from' path '/a' is a proper prefix of 'path' '/a/b'", json::out_of_range&);
+#endif
+    }
+
+    SECTION("from == path is not a proper prefix and must not be rejected")
+    {
+        // "from" equal to "path" is a no-op move; it is not a *proper*
+        // prefix relationship, so this new check must not reject it.
+        json const doc = R"({"a": 1, "b": 2})"_json;
+        json const patch = {{{"op", "move"}, {"from", "/a"}, {"path", "/a"}}};
+        CHECK(doc.patch(patch) == doc);
+    }
+
+    SECTION("raw string prefix that is not a pointer-token prefix must be allowed")
+    {
+        // "/ab" is a string-prefix of "/abc/x" as raw text, but "ab" and
+        // "abc" are different reference tokens, so this is NOT a
+        // pointer-token prefix relationship and the move must succeed.
+        // This is the key case proving the check compares tokens, not
+        // raw pointer text (a naive std::string prefix/rfind check on
+        // the undecoded pointer would wrongly reject this).
+        json const doc = R"({"ab": 1, "abc": {"x": 2}})"_json;
+        json const patch = {{{"op", "move"}, {"from", "/ab"}, {"path", "/abc/x"}}};
+        json const result = R"({"abc": {"x": 1}})"_json;
+        CHECK(doc.patch(patch) == result);
+    }
+
+    SECTION("escaped reference tokens are compared unescaped")
+    {
+        // "from" is the single token "a/b" (escaped as "a~1b"); "path"
+        // addresses member "x" of that same value, so "from" is a
+        // proper (token-level) prefix of "path" and must be rejected.
+        json const doc = R"({"a/b": {"x": 1}})"_json;
+        json const patch = {{{"op", "move"}, {"from", "/a~1b"}, {"path", "/a~1b/x"}}};
+#if JSON_DIAGNOSTIC_POSITIONS
+        CHECK_THROWS_WITH_AS(doc.patch(patch), "[json.exception.out_of_range.414] (bytes 0-17) cannot move value: 'from' path '/a~1b' is a proper prefix of 'path' '/a~1b/x'", json::out_of_range&);
+#else
+        CHECK_THROWS_WITH_AS(doc.patch(patch), "[json.exception.out_of_range.414] cannot move value: 'from' path '/a~1b' is a proper prefix of 'path' '/a~1b/x'", json::out_of_range&);
+#endif
+    }
+
+    SECTION("ordinary valid moves still work")
+    {
+        // unrelated top-level members
+        json const doc1 = R"({"a": 1, "b": 2})"_json;
+        json const patch1 = {{{"op", "move"}, {"from", "/a"}, {"path", "/c"}}};
+        CHECK(doc1.patch(patch1) == R"({"b": 2, "c": 1})"_json);
+
+        // sibling paths that share a textual prefix but are unrelated
+        json const doc2 = R"({"a": {"x": 1}, "b": {"y": 2}})"_json;
+        json const patch2 = {{{"op", "move"}, {"from", "/a/x"}, {"path", "/b/z"}}};
+        CHECK(doc2.patch(patch2) == R"({"a": {}, "b": {"y": 2, "z": 1}})"_json);
+
+        // "path" is a proper prefix of "from" (the reverse relationship,
+        // which RFC 6902 does not forbid)
+        json const doc3 = R"({"a": {"b": 1}})"_json;
+        json const patch3 = {{{"op", "move"}, {"from", "/a/b"}, {"path", "/a"}}};
+        CHECK(doc3.patch(patch3) == R"({"a": 1})"_json);
+    }
+
+    SECTION("root 'from' is a proper prefix of every non-root 'path'")
+    {
+        // the whole document is a proper prefix of any location inside it
+        json const doc = R"({"a": 1})"_json;
+        json const patch = {{{"op", "move"}, {"from", ""}, {"path", "/a"}}};
+#if JSON_DIAGNOSTIC_POSITIONS
+        CHECK_THROWS_WITH_AS(doc.patch(patch), "[json.exception.out_of_range.414] (bytes 0-8) cannot move value: 'from' path '' is a proper prefix of 'path' '/a'", json::out_of_range&);
+#else
+        CHECK_THROWS_WITH_AS(doc.patch(patch), "[json.exception.out_of_range.414] cannot move value: 'from' path '' is a proper prefix of 'path' '/a'", json::out_of_range&);
+#endif
+    }
+
+    SECTION("root 'path' is never a proper prefix violation for a non-root 'from'")
+    {
+        // the reverse of the above: moving a non-root location to the root
+        // is the "path is a prefix of from" relationship, which RFC 6902
+        // permits (already covered generally above; this pins the root
+        // case specifically, since root is the one path with no reference
+        // tokens at all)
+        json const doc = R"({"a": {"b": 1}})"_json;
+        json const patch = {{{"op", "move"}, {"from", "/a"}, {"path", ""}}};
+        CHECK(doc.patch(patch) == R"({"b": 1})"_json);
+    }
+
+    SECTION("the array-append token '-' is an ordinary child token")
+    {
+        // "-" (append-to-array) addresses a location *inside* the array,
+        // so "from" pointing at the array is still a proper prefix of
+        // "path" ending in "-" and must be rejected like any other child.
+        json const doc = R"({"a": [1, 2]})"_json;
+        json const patch = {{{"op", "move"}, {"from", "/a"}, {"path", "/a/-"}}};
+#if JSON_DIAGNOSTIC_POSITIONS
+        CHECK_THROWS_WITH_AS(doc.patch(patch), "[json.exception.out_of_range.414] (bytes 0-13) cannot move value: 'from' path '/a' is a proper prefix of 'path' '/a/-'", json::out_of_range&);
+#else
+        CHECK_THROWS_WITH_AS(doc.patch(patch), "[json.exception.out_of_range.414] cannot move value: 'from' path '/a' is a proper prefix of 'path' '/a/-'", json::out_of_range&);
+#endif
+    }
+}
+
+TEST_CASE("JSON patch - diff emits array removals in descending index order")
+{
+    SECTION("array shrunk to empty")
+    {
+        json const source = {0, 1, 2, 3, 4};
+        json const target = json::array();
+
+        json const patch = json::diff(source, target);
+
+        json const expected = R"(
+            [
+                {"op": "remove", "path": "/4"},
+                {"op": "remove", "path": "/3"},
+                {"op": "remove", "path": "/2"},
+                {"op": "remove", "path": "/1"},
+                {"op": "remove", "path": "/0"}
+            ]
+        )"_json;
+
+        CHECK(patch == expected);
+        CHECK(source.patch(patch) == target);
+    }
+
+    SECTION("array partially shrunk, after a replacement at a common index")
+    {
+        json const source = {0, 1, 2, 3, 4};
+        json const target = {0, 9};
+
+        json const patch = json::diff(source, target);
+
+        // the replacement comes first, then the removals, highest index first
+        json const expected = R"(
+            [
+                {"op": "replace", "path": "/1", "value": 9},
+                {"op": "remove", "path": "/4"},
+                {"op": "remove", "path": "/3"},
+                {"op": "remove", "path": "/2"}
+            ]
+        )"_json;
+
+        CHECK(patch == expected);
+        CHECK(source.patch(patch) == target);
+    }
+
+    SECTION("nested array shrunk")
+    {
+        json const source = {{"a", {0, 1, 2}}};
+        json const target = {{"a", json::array()}};
+
+        json const patch = json::diff(source, target);
+
+        json const expected = R"(
+            [
+                {"op": "remove", "path": "/a/2"},
+                {"op": "remove", "path": "/a/1"},
+                {"op": "remove", "path": "/a/0"}
+            ]
+        )"_json;
+
+        CHECK(patch == expected);
+        CHECK(source.patch(patch) == target);
+    }
+
+    SECTION("many removals still round-trip")
+    {
+        json source = json::array();
+        for (int i = 0; i < 1000; ++i)
+        {
+            source.push_back(i);
+        }
+        json const target = json::array();
+
+        json const patch = json::diff(source, target);
+
+        CHECK(patch.size() == 1000);
+        CHECK(patch.front().at("path") == "/999");
+        CHECK(patch.back().at("path") == "/0");
+        CHECK(source.patch(patch) == target);
+    }
+}
@@ -319,6 +319,44 @@ TEST_CASE("JSON pointers")

                CHECK_THROWS_WITH_AS(j[jp] = 1, throw_msg.c_str(), json::out_of_range&);
                CHECK_THROWS_WITH_AS(j_const[jp] == 1, throw_msg.c_str(), json::out_of_range&);
+
+                // #5395: contains() must not throw for a reference token that is a
+                // syntactically valid array index but numerically exceeds ULLONG_MAX
+                // (causing strtoull() to set errno to ERANGE) -- it should just report
+                // that the pointer does not resolve to an element
+                CHECK(!j.contains(jp));
+                CHECK(!j_const.contains(jp));
+            }
+
+            {
+                // #5395: same as above, but using the exact reproduction from the issue
+                json::json_pointer const jp("/99999999999999999999");
+                std::string const throw_msg = "[json.exception.out_of_range.404] unresolved reference token '99999999999999999999'";
+
+                CHECK_THROWS_WITH_AS(j[jp] = 1, throw_msg.c_str(), json::out_of_range&);
+                CHECK_THROWS_WITH_AS(j_const[jp] == 1, throw_msg.c_str(), json::out_of_range&);
+                CHECK_THROWS_WITH_AS(j.at(jp) = 1, throw_msg.c_str(), json::out_of_range&);
+                CHECK_THROWS_WITH_AS(j_const.at(jp) == 1, throw_msg.c_str(), json::out_of_range&);
+
+                CHECK(!j.contains(jp));
+                CHECK(!j_const.contains(jp));
+            }
+
+            {
+                // #5395: a reference token that is numerically representable in
+                // unsigned long long but exceeds size_type's max (e.g. ULLONG_MAX
+                // itself on typical 64-bit platforms, where size_type's max equals
+                // ULLONG_MAX) must not make contains() throw either
+                json::json_pointer const jp("/18446744073709551615");
+                std::string const throw_msg = "[json.exception.out_of_range.410] array index 18446744073709551615 exceeds size_type";
+
+                CHECK_THROWS_WITH_AS(j[jp] = 1, throw_msg.c_str(), json::out_of_range&);
+                CHECK_THROWS_WITH_AS(j_const[jp] == 1, throw_msg.c_str(), json::out_of_range&);
+                CHECK_THROWS_WITH_AS(j.at(jp) = 1, throw_msg.c_str(), json::out_of_range&);
+                CHECK_THROWS_WITH_AS(j_const.at(jp) == 1, throw_msg.c_str(), json::out_of_range&);
+
+                CHECK(!j.contains(jp));
+                CHECK(!j_const.contains(jp));
            }

            // on some machines, the check below is not constant
@@ -334,6 +372,10 @@ TEST_CASE("JSON pointers")

                CHECK_THROWS_WITH_AS(j[jp] = 1, throw_msg.c_str(), json::out_of_range&);
                CHECK_THROWS_WITH_AS(j_const[jp] == 1, throw_msg.c_str(), json::out_of_range&);
+
+                // #5395: contains() must not throw for a reference token exceeding size_type's max
+                CHECK(!j.contains(jp));
+                CHECK(!j_const.contains(jp));
            }

            DOCTEST_MSVC_SUPPRESS_WARNING_POP
@@ -465,16 +507,6 @@ TEST_CASE("JSON pointers")
        // explicit roundtrip check
        CHECK(j.flatten().unflatten() == j);

-        // an object is only unflattened to an array if one of its keys is the
-        // reference token 0; this must not depend on which key is seen first
-        CHECK(json({{"/2", "x"}}).unflatten() == json({{"2", "x"}}));
-        CHECK(json({{"/10", "y"}, {"/2", "z"}}).unflatten() == json({{"10", "y"}, {"2", "z"}}));
-        CHECK(json({{"/0", 1}, {"/1", 2}}).unflatten() == json({1, 2}));
-        CHECK(json({{"/1", 2}, {"/0", 1}}).unflatten() == json({1, 2}));
-        CHECK(json({{"/0", 1}, {"/2", 3}}).unflatten() == json({1, nullptr, 3}));
-        CHECK(json({{"/a/1", 2}, {"/a/0", 1}}).unflatten() == json({{"a", {1, 2}}}));
-        CHECK(json({{"/a/1", 2}, {"/a/x", 1}}).unflatten() == json({{"a", {{"1", 2}, {"x", 1}}}}));
-
        // roundtrip for primitive values
        json j_null;
        CHECK(j_null.flatten().unflatten() == j_null);
@@ -0,0 +1,34 @@
+//     __ _____ _____ _____
+//  __|  |   __|     |   | |  JSON for Modern C++
+// |  |  |__   |  |  | | | |  version 3.12.0
+// |_____|_____|_____|_|___|  https://github.com/nlohmann/json
+//
+// SPDX-FileCopyrightText: 2013-2026 Niels Lohmann <https://nlohmann.me>
+// SPDX-License-Identifier: MIT
+
+// This file makes sure that none of the internal JSON_HEDLEY_* macros (vendored
+// from https://nemequ.github.io/hedley/, see
+// include/nlohmann/thirdparty/hedley/hedley.hpp) leak into the including
+// translation unit. include/nlohmann/detail/macro_unscope.hpp is supposed to
+// #undef every JSON_HEDLEY_* macro (via hedley_undef.hpp) once json.hpp has
+// been fully processed. See https://github.com/nlohmann/json/issues/5408,
+// where JSON_HEDLEY_PRAGMA, JSON_HEDLEY_PREDICT_TRUE, JSON_HEDLEY_PREDICT_FALSE,
+// and JSON_HEDLEY_CLANG_HAS_DECLSPEC_ATTRIBUTE escaped this cleanup because
+// hedley_undef.hpp had no matching #undef for them.
+//
+// hedley_undef_checks.inc (included below) is generated at CMake configure/
+// build time by cmake/scripts/gen_hedley_undef_check.cmake, which derives the
+// full list of JSON_HEDLEY_* macro names directly from hedley.hpp. That way
+// this test covers every macro Hedley actually defines -- not a hardcoded
+// snapshot that would silently go stale the next time `make update_hedley`
+// runs -- and can never drift from the vendored header.
+
+#include "doctest_compatibility.h"
+
+#include <nlohmann/json.hpp>
+
+TEST_CASE("JSON_HEDLEY macros do not leak after including json.hpp")
+{
+#include "hedley_undef_checks.inc"
+    CHECK(true); // keep an assertion when nothing leaked
+}
@@ -29,10 +29,7 @@ using nlohmann::json;
 #include <limits>
 #include <cstdio>
 #include "make_test_data_available.hpp"
-
-#ifdef JSON_HAS_CPP_17
-    #include <variant>
-#endif
+#include "test_utils.hpp"

 #include "fifo_map.hpp"

@@ -1373,7 +1370,8 @@ TEST_CASE("regression tests 1")
        std::array<uint8_t, 28> key1 = {{ 103, 92, 117, 48, 48, 48, 55, 92, 114, 215, 126, 214, 95, 92, 34, 174, 40, 71, 38, 174, 40, 71, 38, 223, 134, 247, 127, 0 }};
        std::string const key1_str(reinterpret_cast<char*>(key1.data()));
        json const j = key1_str;
-        CHECK_THROWS_WITH_AS(j.dump(), "[json.exception.type_error.316] invalid UTF-8 byte at index 10: 0x7E", json::type_error&);
+        // dump() is nodiscard; the exception is thrown by dump() itself before it would return
+        CHECK_THROWS_WITH_AS(utils::ignore_return_value(j.dump()), "[json.exception.type_error.316] invalid UTF-8 byte at index 10: 0x7E", json::type_error&);
    }

 #if JSON_USE_IMPLICIT_CONVERSIONS
@@ -31,6 +31,8 @@ using ordered_json = nlohmann::ordered_json;
 #include <type_traits>
 #include <utility>

+#include "test_utils.hpp"
+
 #ifdef JSON_HAS_CPP_17
    #include <any>
    #include <variant>
@@ -639,7 +641,8 @@ TEST_CASE("regression tests 2")
                s += static_cast<char>(i);
            }
            dump_test["1"] = s;
-            dump_test.dump(-1, ' ', true, nlohmann::json::error_handler_t::replace);
+            // dump() is nodiscard; this only checks that dumping does not throw/crash
+            utils::ignore_return_value(dump_test.dump(-1, ' ', true, nlohmann::json::error_handler_t::replace));
        }
    }

@@ -731,12 +734,14 @@ TEST_CASE("regression tests 2")
    {
        const std::array<unsigned char, 23> data = {{0x81, 0xA4, 0x64, 0x61, 0x74, 0x61, 0xC4, 0x0F, 0x33, 0x30, 0x30, 0x32, 0x33, 0x34, 0x30, 0x31, 0x30, 0x37, 0x30, 0x35, 0x30, 0x31, 0x30}};
        const json j = json::from_msgpack(data.data(), data.size());
+        // dump() is nodiscard; this only checks that dumping does not throw
        CHECK_NOTHROW(
-            j.dump(4,                             // Indent
-                   ' ',                           // Indent char
-                   false,                         // Ensure ascii
-                   json::error_handler_t::strict  // Error
-                  ));
+            utils::ignore_return_value(
+                j.dump(4,                             // Indent
+                       ' ',                           // Indent char
+                       false,                         // Ensure ascii
+                       json::error_handler_t::strict  // Error
+                      )));
    }

    SECTION("PR #2181 - regression bug with lvalue")
@@ -15,6 +15,8 @@ using nlohmann::json;
 #include <sstream>
 #include <iomanip>

+#include "test_utils.hpp"
+
 TEST_CASE("serialization")
 {
    SECTION("operator<<")
@@ -84,8 +86,9 @@ TEST_CASE("serialization")
        {
            const json j = "ä\xA9ü";

-            CHECK_THROWS_WITH_AS(j.dump(), "[json.exception.type_error.316] invalid UTF-8 byte at index 2: 0xA9", json::type_error&);
-            CHECK_THROWS_WITH_AS(j.dump(1, ' ', false, json::error_handler_t::strict), "[json.exception.type_error.316] invalid UTF-8 byte at index 2: 0xA9", json::type_error&);
+            // dump() is nodiscard; the exception is thrown by dump() itself before it would return
+            CHECK_THROWS_WITH_AS(utils::ignore_return_value(j.dump()), "[json.exception.type_error.316] invalid UTF-8 byte at index 2: 0xA9", json::type_error&);
+            CHECK_THROWS_WITH_AS(utils::ignore_return_value(j.dump(1, ' ', false, json::error_handler_t::strict)), "[json.exception.type_error.316] invalid UTF-8 byte at index 2: 0xA9", json::type_error&);
            CHECK(j.dump(-1, ' ', false, json::error_handler_t::ignore) == "\"äü\"");
            CHECK(j.dump(-1, ' ', false, json::error_handler_t::replace) == "\"ä\xEF\xBF\xBDü\"");
            CHECK(j.dump(-1, ' ', true, json::error_handler_t::replace) == "\"\\u00e4\\ufffd\\u00fc\"");
@@ -95,8 +98,9 @@ TEST_CASE("serialization")
        {
            const json j = "123\xC2";

-            CHECK_THROWS_WITH_AS(j.dump(), "[json.exception.type_error.316] incomplete UTF-8 string; last byte: 0xC2", json::type_error&);
-            CHECK_THROWS_AS(j.dump(1, ' ', false, json::error_handler_t::strict), json::type_error&);
+            // dump() is nodiscard; the exception is thrown by dump() itself before it would return
+            CHECK_THROWS_WITH_AS(utils::ignore_return_value(j.dump()), "[json.exception.type_error.316] incomplete UTF-8 string; last byte: 0xC2", json::type_error&);
+            CHECK_THROWS_AS(utils::ignore_return_value(j.dump(1, ' ', false, json::error_handler_t::strict)), json::type_error&);
            CHECK(j.dump(-1, ' ', false, json::error_handler_t::ignore) == "\"123\"");
            CHECK(j.dump(-1, ' ', false, json::error_handler_t::replace) == "\"123\xEF\xBF\xBD\"");
            CHECK(j.dump(-1, ' ', true, json::error_handler_t::replace) == "\"123\\ufffd\"");
@@ -106,8 +110,9 @@ TEST_CASE("serialization")
        {
            const json j = "123\xF1\xB0\x34\x35\x36";

-            CHECK_THROWS_WITH_AS(j.dump(), "[json.exception.type_error.316] invalid UTF-8 byte at index 5: 0x34", json::type_error&);
-            CHECK_THROWS_AS(j.dump(1, ' ', false, json::error_handler_t::strict), json::type_error&);
+            // dump() is nodiscard; the exception is thrown by dump() itself before it would return
+            CHECK_THROWS_WITH_AS(utils::ignore_return_value(j.dump()), "[json.exception.type_error.316] invalid UTF-8 byte at index 5: 0x34", json::type_error&);
+            CHECK_THROWS_AS(utils::ignore_return_value(j.dump(1, ' ', false, json::error_handler_t::strict)), json::type_error&);
            CHECK(j.dump(-1, ' ', false, json::error_handler_t::ignore) == "\"123456\"");
            CHECK(j.dump(-1, ' ', false, json::error_handler_t::replace) == "\"123\xEF\xBF\xBD\x34\x35\x36\"");
            CHECK(j.dump(-1, ' ', true, json::error_handler_t::replace) == "\"123\\ufffd456\"");
@@ -17,6 +17,7 @@ using nlohmann::json;
 #include <sstream>
 #include <iomanip>
 #include "make_test_data_available.hpp"
+#include "test_utils.hpp"

 TEST_CASE("Unicode (1/5)" * doctest::skip())
 {
@@ -240,7 +241,8 @@ void roundtrip(bool success_expected, const std::string& s)
    if (success_expected)
    {
        // serialization succeeds
-        CHECK_NOTHROW(j.dump());
+        // dump() is nodiscard; this only checks that dumping does not throw
+        CHECK_NOTHROW(utils::ignore_return_value(j.dump()));

        // exclude parse test for U+0000
        if (s[0] != '\0')
@@ -259,7 +261,8 @@ void roundtrip(bool success_expected, const std::string& s)
    else
    {
        // serialization fails
-        CHECK_THROWS_AS(j.dump(), json::type_error&);
+        // dump() is nodiscard; the exception is thrown by dump() itself before it would return
+        CHECK_THROWS_AS(utils::ignore_return_value(j.dump()), json::type_error&);

        // parsing JSON text fails
        CHECK_THROWS_AS(_ = json::parse(ps), json::parse_error&);
@@ -19,6 +19,7 @@ using nlohmann::json;
 #include <iostream>
 #include <iomanip>
 #include "make_test_data_available.hpp"
+#include "test_utils.hpp"

 // this test suite uses static variables with non-trivial destructors
 DOCTEST_CLANG_SUPPRESS_WARNING_PUSH
@@ -97,7 +98,8 @@ void check_utf8dump(bool success_expected, int byte1, int byte2 = -1, int byte3
    else
    {
        // strict mode must throw if success is not expected
-        CHECK_THROWS_AS(j.dump(), json::type_error&);
+        // dump() is nodiscard; the exception is thrown by dump() itself before it would return
+        CHECK_THROWS_AS(utils::ignore_return_value(j.dump()), json::type_error&);
        // ignore and replace must create different dumps
        CHECK(s_ignored != s_replaced);

@@ -19,6 +19,7 @@ using nlohmann::json;
 #include <iostream>
 #include <iomanip>
 #include "make_test_data_available.hpp"
+#include "test_utils.hpp"

 // this test suite uses static variables with non-trivial destructors
 DOCTEST_CLANG_SUPPRESS_WARNING_PUSH
@@ -97,7 +98,8 @@ void check_utf8dump(bool success_expected, int byte1, int byte2 = -1, int byte3
    else
    {
        // strict mode must throw if success is not expected
-        CHECK_THROWS_AS(j.dump(), json::type_error&);
+        // dump() is nodiscard; the exception is thrown by dump() itself before it would return
+        CHECK_THROWS_AS(utils::ignore_return_value(j.dump()), json::type_error&);
        // ignore and replace must create different dumps
        CHECK(s_ignored != s_replaced);

@@ -19,6 +19,7 @@ using nlohmann::json;
 #include <iostream>
 #include <iomanip>
 #include "make_test_data_available.hpp"
+#include "test_utils.hpp"

 // this test suite uses static variables with non-trivial destructors
 DOCTEST_CLANG_SUPPRESS_WARNING_PUSH
@@ -97,7 +98,8 @@ void check_utf8dump(bool success_expected, int byte1, int byte2 = -1, int byte3
    else
    {
        // strict mode must throw if success is not expected
-        CHECK_THROWS_AS(j.dump(), json::type_error&);
+        // dump() is nodiscard; the exception is thrown by dump() itself before it would return
+        CHECK_THROWS_AS(utils::ignore_return_value(j.dump()), json::type_error&);
        // ignore and replace must create different dumps
        CHECK(s_ignored != s_replaced);

@@ -19,6 +19,7 @@ using nlohmann::json;
 #include <iostream>
 #include <iomanip>
 #include "make_test_data_available.hpp"
+#include "test_utils.hpp"

 // this test suite uses static variables with non-trivial destructors
 DOCTEST_CLANG_SUPPRESS_WARNING_PUSH
@@ -97,7 +98,8 @@ void check_utf8dump(bool success_expected, int byte1, int byte2 = -1, int byte3
    else
    {
        // strict mode must throw if success is not expected
-        CHECK_THROWS_AS(j.dump(), json::type_error&);
+        // dump() is nodiscard; the exception is thrown by dump() itself before it would return
+        CHECK_THROWS_AS(utils::ignore_return_value(j.dump()), json::type_error&);
        // ignore and replace must create different dumps
        CHECK(s_ignored != s_replaced);