Drop the version history note for a bug that was never released

The regression came from #5390, which is not in any release. Addresses review comment by @gregmarr.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

docs/mkdocs/docs/api/basic_json/number_float_t.md

@@ -55,10 +55,6 @@ This implementation does exactly follow this approach, as it uses double precisi
 smaller than `-1.79769313486232e+308` and values greater than `1.79769313486232e+308` will be stored as NaN internally
 and be serialized to `null`.
 
-During deserialization (from JSON text or any of the binary formats), a finite number that does not fit into
-`number_float_t` is rejected with [`out_of_range.406`](../../home/exceptions.md#jsonexceptionout_of_range406), for
-example a double-precision number in a binary format when `number_float_t` is `#!cpp float`.
-
 #### Storage
 
 Floating-point number values are stored directly inside a `basic_json` type.

docs/mkdocs/docs/api/basic_json/number_integer_t.md

@@ -47,9 +47,8 @@ With the default values for `NumberIntegerType` (`std::int64_t`), the default va
 
 When the default type is used, the maximal integer number that can be stored is `9223372036854775807` (INT64_MAX) and
 the minimal integer number that can be stored is `-9223372036854775808` (INT64_MIN). Integer numbers that are out of
-range will yield over/underflow when used in a constructor. During deserialization (from JSON text or any of the binary
-formats), too large or small integer numbers will automatically be stored as [`number_unsigned_t`](number_unsigned_t.md)
-or [`number_float_t`](number_float_t.md).
+range will yield over/underflow when used in a constructor. During deserialization, too large or small integer numbers
+will automatically be stored as [`number_unsigned_t`](number_unsigned_t.md) or [`number_float_t`](number_float_t.md).
 
 [RFC 8259](https://tools.ietf.org/html/rfc8259) further states:
 > Note that when such software is used, numbers that are integers and are in the range $[-2^{53}+1, 2^{53}-1]$ are

docs/mkdocs/docs/api/basic_json/number_unsigned_t.md

@@ -48,9 +48,8 @@ With the default values for `NumberUnsignedType` (`std::uint64_t`), the default
 
 When the default type is used, the maximal integer number that can be stored is `18446744073709551615` (UINT64_MAX) and
 the minimal integer number that can be stored is `0`. Integer numbers that are out of range will yield over/underflow
-when used in a constructor. During deserialization (from JSON text or any of the binary formats), too large or small
-integer numbers will automatically be stored as [`number_integer_t`](number_integer_t.md) or
-[`number_float_t`](number_float_t.md).
+when used in a constructor. During deserialization, too large or small integer numbers will automatically be stored
+as [`number_integer_t`](number_integer_t.md) or [`number_float_t`](number_float_t.md).
 
 [RFC 8259](https://tools.ietf.org/html/rfc8259) further states:
 > Note that when such software is used, numbers that are integers and are in the range $[-2^{53}+1, 2^{53}-1]$ are

docs/mkdocs/docs/features/binary_formats/cbor.md

@@ -168,9 +168,9 @@ The library maps CBOR types to JSON value types as follows:
 !!! warning "Negative integer overflow"
 
     CBOR negative integers (major type 1) are decoded as `-1 - n`. If the encoded magnitude `n` is too large for the
-    result to fit into `number_integer_t` (`std::int64_t` by default), the result is stored as `number_float_t`, like
-    a too small integer in JSON text. For example, `-18446744073709551616` (`0x3B` followed by eight `0xFF` bytes) is
-    stored as `-1.8446744073709552e+19`.
+    result to fit into `number_integer_t` (`std::int64_t` by default), parsing fails with a
+    [`parse_error.112`](../../home/exceptions.md#jsonexceptionparse_error112) exception rather than overflowing
+    silently.
 
 !!! warning "Object keys"
 

docs/mkdocs/docs/home/exceptions.md

@@ -331,6 +331,9 @@ An unexpected byte was read in a [binary format](../features/binary_formats/inde
     [json.exception.parse_error.112] parse error at byte 15: syntax error while parsing BSON binary: byte array length cannot be negative, is -1
     ```
     ```
+    [json.exception.parse_error.112] parse error at byte 9: syntax error while parsing CBOR value: negative integer overflow
+    ```
+    ```
     [json.exception.parse_error.112] parse error at byte 5: syntax error while parsing BSON document: document size 6 does not match the number of bytes read (5)
     ```
 
@@ -851,18 +854,13 @@ The JSON Patch operations 'remove' and 'add' cannot be applied to the root eleme
 
 ### json.exception.out_of_range.406
 
-A parsed number could not be stored without changing it to NaN or INF. For the binary formats, this happens when a
-finite floating-point number does not fit into [`number_float_t`](../api/basic_json/number_float_t.md), for example a
-double-precision number when `number_float_t` is `#!cpp float`.
+A parsed number could not be stored as without changing it to NaN or INF.
 
-!!! failure "Example messages"
+!!! failure "Example message"
 
     ```
     number overflow parsing '10E1000'
     ```
-    ```
-    [json.exception.out_of_range.406] syntax error while parsing CBOR value: number overflow
-    ```
 
 ### json.exception.out_of_range.407
 

include/nlohmann/detail/input/binary_reader.hpp

@@ -559,7 +559,7 @@ class binary_reader
             case 0x01: // double
             {
                 double number{};
-                return get_number<double, true>(input_format_t::bson, number) && emit_float(input_format_t::bson, number);
+                return get_number<double, true>(input_format_t::bson, number) && sax->number_float(static_cast<number_float_t>(number), "");
             }
 
             case 0x02: // string
@@ -600,19 +600,19 @@ class binary_reader
             case 0x10: // int32
             {
                 std::int32_t value{};
-                return get_number<std::int32_t, true>(input_format_t::bson, value) && emit_signed(input_format_t::bson, value);
+                return get_number<std::int32_t, true>(input_format_t::bson, value) && sax->number_integer(value);
             }
 
             case 0x12: // int64
             {
                 std::int64_t value{};
-                return get_number<std::int64_t, true>(input_format_t::bson, value) && emit_signed(input_format_t::bson, value);
+                return get_number<std::int64_t, true>(input_format_t::bson, value) && sax->number_integer(value);
             }
 
             case 0x11: // uint64
             {
                 std::uint64_t value{};
-                return get_number<std::uint64_t, true>(input_format_t::bson, value) && emit_unsigned(input_format_t::bson, value);
+                return get_number<std::uint64_t, true>(input_format_t::bson, value) && sax->number_unsigned(value);
             }
 
             default: // anything else is not supported (yet)
@@ -638,19 +638,14 @@ class binary_reader
         {
             return false;
         }
-
-        // the value is -1 - number, which fits into number_integer_t
-        // whenever number does
-        if (JSON_HEDLEY_LIKELY(value_in_range_of<number_integer_t>(number)))
+        const auto max_val = static_cast<NumberType>((std::numeric_limits<number_integer_t>::max)());
+        if (number > max_val)
         {
-            return sax->number_integer(static_cast<number_integer_t>(-1) - static_cast<number_integer_t>(number));
+            return sax->parse_error(chars_read, get_token_string(),
+                                    parse_error::create(112, chars_read,
+                                            exception_message(input_format_t::cbor, "negative integer overflow", "value"), nullptr));
         }
-
-        // like the lexer does for JSON text, store a value too small for
-        // number_integer_t as number_float_t; compute it as long double so
-        // that emit_float sees a finite value and can detect an overflow of
-        // number_float_t
-        return emit_float(input_format_t::cbor, static_cast<long double>(-1) - static_cast<long double>(number));
+        return sax->number_integer(static_cast<number_integer_t>(-1) - static_cast<number_integer_t>(number));
     }
 
     /*!
@@ -707,25 +702,25 @@ class binary_reader
             case 0x18: // Unsigned integer (one-byte uint8_t follows)
             {
                 std::uint8_t number{};
-                return get_number(input_format_t::cbor, number) && emit_unsigned(input_format_t::cbor, number);
+                return get_number(input_format_t::cbor, number) && sax->number_unsigned(number);
             }
 
             case 0x19: // Unsigned integer (two-byte uint16_t follows)
             {
                 std::uint16_t number{};
-                return get_number(input_format_t::cbor, number) && emit_unsigned(input_format_t::cbor, number);
+                return get_number(input_format_t::cbor, number) && sax->number_unsigned(number);
             }
 
             case 0x1A: // Unsigned integer (four-byte uint32_t follows)
             {
                 std::uint32_t number{};
-                return get_number(input_format_t::cbor, number) && emit_unsigned(input_format_t::cbor, number);
+                return get_number(input_format_t::cbor, number) && sax->number_unsigned(number);
             }
 
             case 0x1B: // Unsigned integer (eight-byte uint64_t follows)
             {
                 std::uint64_t number{};
-                return get_number(input_format_t::cbor, number) && emit_unsigned(input_format_t::cbor, number);
+                return get_number(input_format_t::cbor, number) && sax->number_unsigned(number);
             }
 
             // Negative integer -1-0x00..-1-0x17 (-1..-24)
@@ -1170,13 +1165,13 @@ class binary_reader
             case 0xFA: // Single-Precision Float (four-byte IEEE 754)
             {
                 float number{};
-                return get_number(input_format_t::cbor, number) && emit_float(input_format_t::cbor, number);
+                return get_number(input_format_t::cbor, number) && sax->number_float(static_cast<number_float_t>(number), "");
             }
 
             case 0xFB: // Double-Precision Float (eight-byte IEEE 754)
             {
                 double number{};
-                return get_number(input_format_t::cbor, number) && emit_float(input_format_t::cbor, number);
+                return get_number(input_format_t::cbor, number) && sax->number_float(static_cast<number_float_t>(number), "");
             }
 
             default: // anything else (0xFF is handled inside the other types)
@@ -1940,61 +1935,61 @@ class binary_reader
             case 0xCA: // float 32
             {
                 float number{};
-                return get_number(input_format_t::msgpack, number) && emit_float(input_format_t::msgpack, number);
+                return get_number(input_format_t::msgpack, number) && sax->number_float(static_cast<number_float_t>(number), "");
             }
 
             case 0xCB: // float 64
             {
                 double number{};
-                return get_number(input_format_t::msgpack, number) && emit_float(input_format_t::msgpack, number);
+                return get_number(input_format_t::msgpack, number) && sax->number_float(static_cast<number_float_t>(number), "");
             }
 
             case 0xCC: // uint 8
             {
                 std::uint8_t number{};
-                return get_number(input_format_t::msgpack, number) && emit_unsigned(input_format_t::msgpack, number);
+                return get_number(input_format_t::msgpack, number) && sax->number_unsigned(number);
             }
 
             case 0xCD: // uint 16
             {
                 std::uint16_t number{};
-                return get_number(input_format_t::msgpack, number) && emit_unsigned(input_format_t::msgpack, number);
+                return get_number(input_format_t::msgpack, number) && sax->number_unsigned(number);
             }
 
             case 0xCE: // uint 32
             {
                 std::uint32_t number{};
-                return get_number(input_format_t::msgpack, number) && emit_unsigned(input_format_t::msgpack, number);
+                return get_number(input_format_t::msgpack, number) && sax->number_unsigned(number);
             }
 
             case 0xCF: // uint 64
             {
                 std::uint64_t number{};
-                return get_number(input_format_t::msgpack, number) && emit_unsigned(input_format_t::msgpack, number);
+                return get_number(input_format_t::msgpack, number) && sax->number_unsigned(number);
             }
 
             case 0xD0: // int 8
             {
                 std::int8_t number{};
-                return get_number(input_format_t::msgpack, number) && emit_signed(input_format_t::msgpack, number);
+                return get_number(input_format_t::msgpack, number) && sax->number_integer(number);
             }
 
             case 0xD1: // int 16
             {
                 std::int16_t number{};
-                return get_number(input_format_t::msgpack, number) && emit_signed(input_format_t::msgpack, number);
+                return get_number(input_format_t::msgpack, number) && sax->number_integer(number);
             }
 
             case 0xD2: // int 32
             {
                 std::int32_t number{};
-                return get_number(input_format_t::msgpack, number) && emit_signed(input_format_t::msgpack, number);
+                return get_number(input_format_t::msgpack, number) && sax->number_integer(number);
             }
 
             case 0xD3: // int 64
             {
                 std::int64_t number{};
-                return get_number(input_format_t::msgpack, number) && emit_signed(input_format_t::msgpack, number);
+                return get_number(input_format_t::msgpack, number) && sax->number_integer(number);
             }
 
             case 0xDC: // array 16
@@ -2927,7 +2922,7 @@ class binary_reader
                         {
                             return sax->parse_error(chars_read, get_token_string(), out_of_range::create(408, exception_message(input_format, "excessive ndarray size caused overflow", "size"), nullptr));
                         }
-                        if (JSON_HEDLEY_UNLIKELY(!emit_unsigned(input_format, i)))
+                        if (JSON_HEDLEY_UNLIKELY(!sax->number_unsigned(static_cast<number_unsigned_t>(i))))
                         {
                             return false;
                         }
@@ -3059,37 +3054,37 @@ class binary_reader
                     break;
                 }
                 std::uint8_t number{};
-                return get_number(input_format, number) && emit_unsigned(input_format, number);
+                return get_number(input_format, number) && sax->number_unsigned(number);
             }
 
             case 'U':
             {
                 std::uint8_t number{};
-                return get_number(input_format, number) && emit_unsigned(input_format, number);
+                return get_number(input_format, number) && sax->number_unsigned(number);
             }
 
             case 'i':
             {
                 std::int8_t number{};
-                return get_number(input_format, number) && emit_signed(input_format, number);
+                return get_number(input_format, number) && sax->number_integer(number);
             }
 
             case 'I':
             {
                 std::int16_t number{};
-                return get_number(input_format, number) && emit_signed(input_format, number);
+                return get_number(input_format, number) && sax->number_integer(number);
             }
 
             case 'l':
             {
                 std::int32_t number{};
-                return get_number(input_format, number) && emit_signed(input_format, number);
+                return get_number(input_format, number) && sax->number_integer(number);
             }
 
             case 'L':
             {
                 std::int64_t number{};
-                return get_number(input_format, number) && emit_signed(input_format, number);
+                return get_number(input_format, number) && sax->number_integer(number);
             }
 
             case 'u':
@@ -3099,7 +3094,7 @@ class binary_reader
                     break;
                 }
                 std::uint16_t number{};
-                return get_number(input_format, number) && emit_unsigned(input_format, number);
+                return get_number(input_format, number) && sax->number_unsigned(number);
             }
 
             case 'm':
@@ -3109,7 +3104,7 @@ class binary_reader
                     break;
                 }
                 std::uint32_t number{};
-                return get_number(input_format, number) && emit_unsigned(input_format, number);
+                return get_number(input_format, number) && sax->number_unsigned(number);
             }
 
             case 'M':
@@ -3119,7 +3114,7 @@ class binary_reader
                     break;
                 }
                 std::uint64_t number{};
-                return get_number(input_format, number) && emit_unsigned(input_format, number);
+                return get_number(input_format, number) && sax->number_unsigned(number);
             }
 
             case 'h':
@@ -3177,13 +3172,13 @@ class binary_reader
             case 'd':
             {
                 float number{};
-                return get_number(input_format, number) && emit_float(input_format, number);
+                return get_number(input_format, number) && sax->number_float(static_cast<number_float_t>(number), "");
             }
 
             case 'D':
             {
                 double number{};
-                return get_number(input_format, number) && emit_float(input_format, number);
+                return get_number(input_format, number) && sax->number_float(static_cast<number_float_t>(number), "");
             }
 
             case 'H':
@@ -3650,13 +3645,13 @@ class binary_reader
             case 0x8E: // binary32
             {
                 float number{};
-                return get_number(input_format_t::bon8, number) && emit_float(input_format_t::bon8, number);
+                return get_number(input_format_t::bon8, number) && sax->number_float(static_cast<number_float_t>(number), "");
             }
 
             case 0x8F: // binary64
             {
                 double number{};
-                return get_number(input_format_t::bon8, number) && emit_float(input_format_t::bon8, number);
+                return get_number(input_format_t::bon8, number) && sax->number_float(static_cast<number_float_t>(number), "");
             }
 
             case 0xF8:
@@ -3722,9 +3717,7 @@ class binary_reader
     @brief pass an integer to the SAX parser
 
     Non-negative integers are passed as unsigned, negative integers as signed
-    numbers, like the other binary formats do. A value that does not fit the
-    number type is passed as described for @ref emit_unsigned and
-    @ref emit_signed.
+    numbers, like the other binary formats do.
 
     @param[in] number  the integer
     @return whether the SAX parser accepted the value
@@ -3733,9 +3726,9 @@ class binary_reader
     {
         if (number >= 0)
         {
-            return emit_unsigned(input_format_t::bon8, static_cast<std::uint64_t>(number));
+            return sax->number_unsigned(static_cast<number_unsigned_t>(number));
         }
-        return emit_signed(input_format_t::bon8, number);
+        return sax->number_integer(static_cast<number_integer_t>(number));
     }
 
     /*!
@@ -3792,7 +3785,8 @@ class binary_reader
             value = (value << 8) | static_cast<std::int64_t>(current);
         }
 
-        return emit_bon8_integer(negative ? -(value + offset) : value + offset);
+        return negative ? sax->number_integer(static_cast<number_integer_t>(-(value + offset)))
+               : sax->number_unsigned(static_cast<number_unsigned_t>(value + offset));
     }
 
     /*!
@@ -4089,88 +4083,6 @@ class binary_reader
         return true;
     }
 
-    /*!
-    @brief pass a signed integer read from the input to the SAX parser
-
-    Like the lexer does for JSON text, a value that does not fit into
-    number_integer_t is passed as number_unsigned_t if it is non-negative and
-    fits there, and as number_float_t otherwise. With the default number
-    types, every integer the binary formats can encode fits, so this only
-    matters for narrower custom number types.
-
-    @tparam NumberType a signed integer type
-    @param[in] format  the current format (for diagnostics)
-    @param[in] number  the integer
-    @return whether the SAX parser accepted the value
-
-    @throw out_of_range.406 if @a number overflows number_float_t (see
-           @ref emit_float)
-    */
-    template<typename NumberType>
-    bool emit_signed(const input_format_t format, const NumberType number)
-    {
-        if (JSON_HEDLEY_LIKELY(value_in_range_of<number_integer_t>(number)))
-        {
-            return sax->number_integer(static_cast<number_integer_t>(number));
-        }
-        if (value_in_range_of<number_unsigned_t>(number))
-        {
-            return sax->number_unsigned(static_cast<number_unsigned_t>(number));
-        }
-        return emit_float(format, number);
-    }
-
-    /*!
-    @brief pass an unsigned integer read from the input to the SAX parser
-
-    Like the lexer does for JSON text, a value that does not fit into
-    number_unsigned_t is passed as number_float_t.
-
-    @tparam NumberType an unsigned integer type
-    @param[in] format  the current format (for diagnostics)
-    @param[in] number  the integer
-    @return whether the SAX parser accepted the value
-
-    @throw out_of_range.406 if @a number overflows number_float_t (see
-           @ref emit_float)
-    */
-    template<typename NumberType>
-    bool emit_unsigned(const input_format_t format, const NumberType number)
-    {
-        if (JSON_HEDLEY_LIKELY(value_in_range_of<number_unsigned_t>(number)))
-        {
-            return sax->number_unsigned(static_cast<number_unsigned_t>(number));
-        }
-        return emit_float(format, number);
-    }
-
-    /*!
-    @brief pass a floating-point number read from the input to the SAX parser
-
-    Like the lexer does for JSON text, a finite value that overflows
-    number_float_t is rejected instead of silently becoming infinity. Infinity
-    and NaN in the input are passed on unchanged. Integers only overflow if
-    number_float_t cannot represent 2^64, e.g., a half-precision type.
-
-    @tparam NumberType a floating-point or integer type
-    @param[in] format  the current format (for diagnostics)
-    @param[in] number  the number
-    @return whether the SAX parser accepted the value
-
-    @throw out_of_range.406 if a finite @a number overflows number_float_t
-    */
-    template<typename NumberType>
-    bool emit_float(const input_format_t format, const NumberType number)
-    {
-        const auto result = static_cast<number_float_t>(number);
-        if (JSON_HEDLEY_UNLIKELY(std::isfinite(number) && !std::isfinite(result)))
-        {
-            return sax->parse_error(chars_read, get_token_string(),
-                                    out_of_range::create(406, exception_message(format, "number overflow", "value"), nullptr));
-        }
-        return sax->number_float(result, "");
-    }
-
     /*!
     @brief create a string by reading characters from the input
 

include/nlohmann/json.hpp

@@ -1307,15 +1307,65 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
     */
     template<bool Ordered>
     static compare_result compare_leaves(const_reference lhs, const_reference rhs) noexcept
+    {
+        return compare_leaves(lhs, rhs, std::integral_constant<bool, Ordered> {});
+    }
+
+    /// @brief compare two leaves that are only being checked for equality
+    static compare_result compare_leaves(const_reference lhs, const_reference rhs, std::false_type /*ordered*/) noexcept
     {
         if (lhs == rhs)
         {
             return compare_result::equal;
         }
 
-        return order_leaves(lhs, rhs, std::integral_constant<bool, Ordered> {});
+        return order_leaves(lhs, rhs, std::false_type {});
     }
 
+#if JSON_HAS_THREE_WAY_COMPARISON
+    /*!
+    @brief compare two leaves that are being ordered, for operator<=>
+
+    Reached only from operator<=>, so the leaves must be classified exactly
+    as operator<=> classifies them - which is not the same as asking
+    == and then order_leaves(), the way the other overload does it. The two
+    disagree on a binary value: == also compares the subtype, but <=> compares
+    only the bytes, through std::vector<std::uint8_t>::operator<=>. Using <=>
+    itself here keeps a leaf pair classified the same way regardless of how
+    deep it is nested - == first would again call operator<=> a level down
+    through order_leaves(), but call it after a mismatching == already ended
+    the comparison for a pair that <=> alone would still call equivalent.
+    */
+    static compare_result compare_leaves(const_reference lhs, const_reference rhs, std::true_type /*ordered*/) noexcept
+    {
+        const std::partial_ordering order = lhs <=> rhs; // *NOPAD*
+        if (order == 0)
+        {
+            return compare_result::equal;
+        }
+        if (order < 0)
+        {
+            return compare_result::less;
+        }
+        if (order > 0)
+        {
+            return compare_result::greater;
+        }
+        return compare_result::unordered;
+    }
+#else
+    /// @brief compare two leaves that are being ordered, for operator<
+    static compare_result compare_leaves(const_reference lhs, const_reference rhs, std::true_type /*ordered*/) noexcept
+    {
+        if (lhs == rhs)
+        {
+            return compare_result::equal;
+        }
+
+        return order_leaves(lhs, rhs, std::true_type {});
+    }
+#endif
+
     /*!
     @brief compare two object keys
 

single_include/nlohmann/json.hpp

@@ -13326,7 +13326,7 @@ class binary_reader
             case 0x01: // double
             {
                 double number{};
-                return get_number<double, true>(input_format_t::bson, number) && emit_float(input_format_t::bson, number);
+                return get_number<double, true>(input_format_t::bson, number) && sax->number_float(static_cast<number_float_t>(number), "");
             }
 
             case 0x02: // string
@@ -13367,19 +13367,19 @@ class binary_reader
             case 0x10: // int32
             {
                 std::int32_t value{};
-                return get_number<std::int32_t, true>(input_format_t::bson, value) && emit_signed(input_format_t::bson, value);
+                return get_number<std::int32_t, true>(input_format_t::bson, value) && sax->number_integer(value);
             }
 
             case 0x12: // int64
             {
                 std::int64_t value{};
-                return get_number<std::int64_t, true>(input_format_t::bson, value) && emit_signed(input_format_t::bson, value);
+                return get_number<std::int64_t, true>(input_format_t::bson, value) && sax->number_integer(value);
             }
 
             case 0x11: // uint64
             {
                 std::uint64_t value{};
-                return get_number<std::uint64_t, true>(input_format_t::bson, value) && emit_unsigned(input_format_t::bson, value);
+                return get_number<std::uint64_t, true>(input_format_t::bson, value) && sax->number_unsigned(value);
             }
 
             default: // anything else is not supported (yet)
@@ -13405,19 +13405,14 @@ class binary_reader
         {
             return false;
         }
-
-        // the value is -1 - number, which fits into number_integer_t
-        // whenever number does
-        if (JSON_HEDLEY_LIKELY(value_in_range_of<number_integer_t>(number)))
+        const auto max_val = static_cast<NumberType>((std::numeric_limits<number_integer_t>::max)());
+        if (number > max_val)
         {
-            return sax->number_integer(static_cast<number_integer_t>(-1) - static_cast<number_integer_t>(number));
+            return sax->parse_error(chars_read, get_token_string(),
+                                    parse_error::create(112, chars_read,
+                                            exception_message(input_format_t::cbor, "negative integer overflow", "value"), nullptr));
         }
-
-        // like the lexer does for JSON text, store a value too small for
-        // number_integer_t as number_float_t; compute it as long double so
-        // that emit_float sees a finite value and can detect an overflow of
-        // number_float_t
-        return emit_float(input_format_t::cbor, static_cast<long double>(-1) - static_cast<long double>(number));
+        return sax->number_integer(static_cast<number_integer_t>(-1) - static_cast<number_integer_t>(number));
     }
 
     /*!
@@ -13474,25 +13469,25 @@ class binary_reader
             case 0x18: // Unsigned integer (one-byte uint8_t follows)
             {
                 std::uint8_t number{};
-                return get_number(input_format_t::cbor, number) && emit_unsigned(input_format_t::cbor, number);
+                return get_number(input_format_t::cbor, number) && sax->number_unsigned(number);
             }
 
             case 0x19: // Unsigned integer (two-byte uint16_t follows)
             {
                 std::uint16_t number{};
-                return get_number(input_format_t::cbor, number) && emit_unsigned(input_format_t::cbor, number);
+                return get_number(input_format_t::cbor, number) && sax->number_unsigned(number);
             }
 
             case 0x1A: // Unsigned integer (four-byte uint32_t follows)
             {
                 std::uint32_t number{};
-                return get_number(input_format_t::cbor, number) && emit_unsigned(input_format_t::cbor, number);
+                return get_number(input_format_t::cbor, number) && sax->number_unsigned(number);
             }
 
             case 0x1B: // Unsigned integer (eight-byte uint64_t follows)
             {
                 std::uint64_t number{};
-                return get_number(input_format_t::cbor, number) && emit_unsigned(input_format_t::cbor, number);
+                return get_number(input_format_t::cbor, number) && sax->number_unsigned(number);
             }
 
             // Negative integer -1-0x00..-1-0x17 (-1..-24)
@@ -13937,13 +13932,13 @@ class binary_reader
             case 0xFA: // Single-Precision Float (four-byte IEEE 754)
             {
                 float number{};
-                return get_number(input_format_t::cbor, number) && emit_float(input_format_t::cbor, number);
+                return get_number(input_format_t::cbor, number) && sax->number_float(static_cast<number_float_t>(number), "");
             }
 
             case 0xFB: // Double-Precision Float (eight-byte IEEE 754)
             {
                 double number{};
-                return get_number(input_format_t::cbor, number) && emit_float(input_format_t::cbor, number);
+                return get_number(input_format_t::cbor, number) && sax->number_float(static_cast<number_float_t>(number), "");
             }
 
             default: // anything else (0xFF is handled inside the other types)
@@ -14707,61 +14702,61 @@ class binary_reader
             case 0xCA: // float 32
             {
                 float number{};
-                return get_number(input_format_t::msgpack, number) && emit_float(input_format_t::msgpack, number);
+                return get_number(input_format_t::msgpack, number) && sax->number_float(static_cast<number_float_t>(number), "");
             }
 
             case 0xCB: // float 64
             {
                 double number{};
-                return get_number(input_format_t::msgpack, number) && emit_float(input_format_t::msgpack, number);
+                return get_number(input_format_t::msgpack, number) && sax->number_float(static_cast<number_float_t>(number), "");
             }
 
             case 0xCC: // uint 8
             {
                 std::uint8_t number{};
-                return get_number(input_format_t::msgpack, number) && emit_unsigned(input_format_t::msgpack, number);
+                return get_number(input_format_t::msgpack, number) && sax->number_unsigned(number);
             }
 
             case 0xCD: // uint 16
             {
                 std::uint16_t number{};
-                return get_number(input_format_t::msgpack, number) && emit_unsigned(input_format_t::msgpack, number);
+                return get_number(input_format_t::msgpack, number) && sax->number_unsigned(number);
             }
 
             case 0xCE: // uint 32
             {
                 std::uint32_t number{};
-                return get_number(input_format_t::msgpack, number) && emit_unsigned(input_format_t::msgpack, number);
+                return get_number(input_format_t::msgpack, number) && sax->number_unsigned(number);
             }
 
             case 0xCF: // uint 64
             {
                 std::uint64_t number{};
-                return get_number(input_format_t::msgpack, number) && emit_unsigned(input_format_t::msgpack, number);
+                return get_number(input_format_t::msgpack, number) && sax->number_unsigned(number);
             }
 
             case 0xD0: // int 8
             {
                 std::int8_t number{};
-                return get_number(input_format_t::msgpack, number) && emit_signed(input_format_t::msgpack, number);
+                return get_number(input_format_t::msgpack, number) && sax->number_integer(number);
             }
 
             case 0xD1: // int 16
             {
                 std::int16_t number{};
-                return get_number(input_format_t::msgpack, number) && emit_signed(input_format_t::msgpack, number);
+                return get_number(input_format_t::msgpack, number) && sax->number_integer(number);
             }
 
             case 0xD2: // int 32
             {
                 std::int32_t number{};
-                return get_number(input_format_t::msgpack, number) && emit_signed(input_format_t::msgpack, number);
+                return get_number(input_format_t::msgpack, number) && sax->number_integer(number);
             }
 
             case 0xD3: // int 64
             {
                 std::int64_t number{};
-                return get_number(input_format_t::msgpack, number) && emit_signed(input_format_t::msgpack, number);
+                return get_number(input_format_t::msgpack, number) && sax->number_integer(number);
             }
 
             case 0xDC: // array 16
@@ -15694,7 +15689,7 @@ class binary_reader
                         {
                             return sax->parse_error(chars_read, get_token_string(), out_of_range::create(408, exception_message(input_format, "excessive ndarray size caused overflow", "size"), nullptr));
                         }
-                        if (JSON_HEDLEY_UNLIKELY(!emit_unsigned(input_format, i)))
+                        if (JSON_HEDLEY_UNLIKELY(!sax->number_unsigned(static_cast<number_unsigned_t>(i))))
                         {
                             return false;
                         }
@@ -15826,37 +15821,37 @@ class binary_reader
                     break;
                 }
                 std::uint8_t number{};
-                return get_number(input_format, number) && emit_unsigned(input_format, number);
+                return get_number(input_format, number) && sax->number_unsigned(number);
             }
 
             case 'U':
             {
                 std::uint8_t number{};
-                return get_number(input_format, number) && emit_unsigned(input_format, number);
+                return get_number(input_format, number) && sax->number_unsigned(number);
             }
 
             case 'i':
             {
                 std::int8_t number{};
-                return get_number(input_format, number) && emit_signed(input_format, number);
+                return get_number(input_format, number) && sax->number_integer(number);
             }
 
             case 'I':
             {
                 std::int16_t number{};
-                return get_number(input_format, number) && emit_signed(input_format, number);
+                return get_number(input_format, number) && sax->number_integer(number);
             }
 
             case 'l':
             {
                 std::int32_t number{};
-                return get_number(input_format, number) && emit_signed(input_format, number);
+                return get_number(input_format, number) && sax->number_integer(number);
             }
 
             case 'L':
             {
                 std::int64_t number{};
-                return get_number(input_format, number) && emit_signed(input_format, number);
+                return get_number(input_format, number) && sax->number_integer(number);
             }
 
             case 'u':
@@ -15866,7 +15861,7 @@ class binary_reader
                     break;
                 }
                 std::uint16_t number{};
-                return get_number(input_format, number) && emit_unsigned(input_format, number);
+                return get_number(input_format, number) && sax->number_unsigned(number);
             }
 
             case 'm':
@@ -15876,7 +15871,7 @@ class binary_reader
                     break;
                 }
                 std::uint32_t number{};
-                return get_number(input_format, number) && emit_unsigned(input_format, number);
+                return get_number(input_format, number) && sax->number_unsigned(number);
             }
 
             case 'M':
@@ -15886,7 +15881,7 @@ class binary_reader
                     break;
                 }
                 std::uint64_t number{};
-                return get_number(input_format, number) && emit_unsigned(input_format, number);
+                return get_number(input_format, number) && sax->number_unsigned(number);
             }
 
             case 'h':
@@ -15944,13 +15939,13 @@ class binary_reader
             case 'd':
             {
                 float number{};
-                return get_number(input_format, number) && emit_float(input_format, number);
+                return get_number(input_format, number) && sax->number_float(static_cast<number_float_t>(number), "");
             }
 
             case 'D':
             {
                 double number{};
-                return get_number(input_format, number) && emit_float(input_format, number);
+                return get_number(input_format, number) && sax->number_float(static_cast<number_float_t>(number), "");
             }
 
             case 'H':
@@ -16417,13 +16412,13 @@ class binary_reader
             case 0x8E: // binary32
             {
                 float number{};
-                return get_number(input_format_t::bon8, number) && emit_float(input_format_t::bon8, number);
+                return get_number(input_format_t::bon8, number) && sax->number_float(static_cast<number_float_t>(number), "");
             }
 
             case 0x8F: // binary64
             {
                 double number{};
-                return get_number(input_format_t::bon8, number) && emit_float(input_format_t::bon8, number);
+                return get_number(input_format_t::bon8, number) && sax->number_float(static_cast<number_float_t>(number), "");
             }
 
             case 0xF8:
@@ -16489,9 +16484,7 @@ class binary_reader
     @brief pass an integer to the SAX parser
 
     Non-negative integers are passed as unsigned, negative integers as signed
-    numbers, like the other binary formats do. A value that does not fit the
-    number type is passed as described for @ref emit_unsigned and
-    @ref emit_signed.
+    numbers, like the other binary formats do.
 
     @param[in] number  the integer
     @return whether the SAX parser accepted the value
@@ -16500,9 +16493,9 @@ class binary_reader
     {
         if (number >= 0)
         {
-            return emit_unsigned(input_format_t::bon8, static_cast<std::uint64_t>(number));
+            return sax->number_unsigned(static_cast<number_unsigned_t>(number));
         }
-        return emit_signed(input_format_t::bon8, number);
+        return sax->number_integer(static_cast<number_integer_t>(number));
     }
 
     /*!
@@ -16559,7 +16552,8 @@ class binary_reader
             value = (value << 8) | static_cast<std::int64_t>(current);
         }
 
-        return emit_bon8_integer(negative ? -(value + offset) : value + offset);
+        return negative ? sax->number_integer(static_cast<number_integer_t>(-(value + offset)))
+               : sax->number_unsigned(static_cast<number_unsigned_t>(value + offset));
     }
 
     /*!
@@ -16856,88 +16850,6 @@ class binary_reader
         return true;
     }
 
-    /*!
-    @brief pass a signed integer read from the input to the SAX parser
-
-    Like the lexer does for JSON text, a value that does not fit into
-    number_integer_t is passed as number_unsigned_t if it is non-negative and
-    fits there, and as number_float_t otherwise. With the default number
-    types, every integer the binary formats can encode fits, so this only
-    matters for narrower custom number types.
-
-    @tparam NumberType a signed integer type
-    @param[in] format  the current format (for diagnostics)
-    @param[in] number  the integer
-    @return whether the SAX parser accepted the value
-
-    @throw out_of_range.406 if @a number overflows number_float_t (see
-           @ref emit_float)
-    */
-    template<typename NumberType>
-    bool emit_signed(const input_format_t format, const NumberType number)
-    {
-        if (JSON_HEDLEY_LIKELY(value_in_range_of<number_integer_t>(number)))
-        {
-            return sax->number_integer(static_cast<number_integer_t>(number));
-        }
-        if (value_in_range_of<number_unsigned_t>(number))
-        {
-            return sax->number_unsigned(static_cast<number_unsigned_t>(number));
-        }
-        return emit_float(format, number);
-    }
-
-    /*!
-    @brief pass an unsigned integer read from the input to the SAX parser
-
-    Like the lexer does for JSON text, a value that does not fit into
-    number_unsigned_t is passed as number_float_t.
-
-    @tparam NumberType an unsigned integer type
-    @param[in] format  the current format (for diagnostics)
-    @param[in] number  the integer
-    @return whether the SAX parser accepted the value
-
-    @throw out_of_range.406 if @a number overflows number_float_t (see
-           @ref emit_float)
-    */
-    template<typename NumberType>
-    bool emit_unsigned(const input_format_t format, const NumberType number)
-    {
-        if (JSON_HEDLEY_LIKELY(value_in_range_of<number_unsigned_t>(number)))
-        {
-            return sax->number_unsigned(static_cast<number_unsigned_t>(number));
-        }
-        return emit_float(format, number);
-    }
-
-    /*!
-    @brief pass a floating-point number read from the input to the SAX parser
-
-    Like the lexer does for JSON text, a finite value that overflows
-    number_float_t is rejected instead of silently becoming infinity. Infinity
-    and NaN in the input are passed on unchanged. Integers only overflow if
-    number_float_t cannot represent 2^64, e.g., a half-precision type.
-
-    @tparam NumberType a floating-point or integer type
-    @param[in] format  the current format (for diagnostics)
-    @param[in] number  the number
-    @return whether the SAX parser accepted the value
-
-    @throw out_of_range.406 if a finite @a number overflows number_float_t
-    */
-    template<typename NumberType>
-    bool emit_float(const input_format_t format, const NumberType number)
-    {
-        const auto result = static_cast<number_float_t>(number);
-        if (JSON_HEDLEY_UNLIKELY(std::isfinite(number) && !std::isfinite(result)))
-        {
-            return sax->parse_error(chars_read, get_token_string(),
-                                    out_of_range::create(406, exception_message(format, "number overflow", "value"), nullptr));
-        }
-        return sax->number_float(result, "");
-    }
-
     /*!
     @brief create a string by reading characters from the input
 
@@ -27476,15 +27388,65 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
     */
     template<bool Ordered>
     static compare_result compare_leaves(const_reference lhs, const_reference rhs) noexcept
+    {
+        return compare_leaves(lhs, rhs, std::integral_constant<bool, Ordered> {});
+    }
+
+    /// @brief compare two leaves that are only being checked for equality
+    static compare_result compare_leaves(const_reference lhs, const_reference rhs, std::false_type /*ordered*/) noexcept
     {
         if (lhs == rhs)
         {
             return compare_result::equal;
         }
 
-        return order_leaves(lhs, rhs, std::integral_constant<bool, Ordered> {});
+        return order_leaves(lhs, rhs, std::false_type {});
     }
 
+#if JSON_HAS_THREE_WAY_COMPARISON
+    /*!
+    @brief compare two leaves that are being ordered, for operator<=>
+
+    Reached only from operator<=>, so the leaves must be classified exactly
+    as operator<=> classifies them - which is not the same as asking
+    == and then order_leaves(), the way the other overload does it. The two
+    disagree on a binary value: == also compares the subtype, but <=> compares
+    only the bytes, through std::vector<std::uint8_t>::operator<=>. Using <=>
+    itself here keeps a leaf pair classified the same way regardless of how
+    deep it is nested - == first would again call operator<=> a level down
+    through order_leaves(), but call it after a mismatching == already ended
+    the comparison for a pair that <=> alone would still call equivalent.
+    */
+    static compare_result compare_leaves(const_reference lhs, const_reference rhs, std::true_type /*ordered*/) noexcept
+    {
+        const std::partial_ordering order = lhs <=> rhs; // *NOPAD*
+        if (order == 0)
+        {
+            return compare_result::equal;
+        }
+        if (order < 0)
+        {
+            return compare_result::less;
+        }
+        if (order > 0)
+        {
+            return compare_result::greater;
+        }
+        return compare_result::unordered;
+    }
+#else
+    /// @brief compare two leaves that are being ordered, for operator<
+    static compare_result compare_leaves(const_reference lhs, const_reference rhs, std::true_type /*ordered*/) noexcept
+    {
+        if (lhs == rhs)
+        {
+            return compare_result::equal;
+        }
+
+        return order_leaves(lhs, rhs, std::true_type {});
+    }
+#endif
+
     /*!
     @brief compare two object keys
 

tests/src/unit-binary_formats.cpp

@@ -11,12 +11,7 @@
 #include <nlohmann/json.hpp>
 using nlohmann::json;
 
-#include <cmath>
 #include <fstream>
-#include <limits>
-#include <map>
-#include <string>
-#include <vector>
 #include "make_test_data_available.hpp"
 
 TEST_CASE("Binary Formats" * doctest::skip())
@@ -229,139 +224,3 @@ TEST_CASE("Binary Formats" * doctest::skip())
         CHECK((100.0 * double(ubjson_3_size) / double(json_size)) == Approx(89.450));
     }
 }
-
-namespace
-{
-// the binary formats as function pointers for "Binary formats with narrow number types";
-// named functions rather than lambdas, because clang 3.5 cannot convert a lambda
-// to a function pointer in the braced initializer of the format table
-using narrow_json = nlohmann::basic_json<std::map, std::vector, std::string, bool, std::int32_t, std::uint32_t, float>;
-using bytes = std::vector<std::uint8_t>;
-
-bytes encode_cbor(const json& j)
-{
-    return json::to_cbor(j);
-}
-narrow_json decode_cbor(const bytes& v, bool allow_exceptions)
-{
-    return narrow_json::from_cbor(v, true, allow_exceptions);
-}
-
-bytes encode_msgpack(const json& j)
-{
-    return json::to_msgpack(j);
-}
-narrow_json decode_msgpack(const bytes& v, bool allow_exceptions)
-{
-    return narrow_json::from_msgpack(v, true, allow_exceptions);
-}
-
-bytes encode_ubjson(const json& j)
-{
-    return json::to_ubjson(j);
-}
-narrow_json decode_ubjson(const bytes& v, bool allow_exceptions)
-{
-    return narrow_json::from_ubjson(v, true, allow_exceptions);
-}
-
-bytes encode_bjdata(const json& j)
-{
-    return json::to_bjdata(j);
-}
-narrow_json decode_bjdata(const bytes& v, bool allow_exceptions)
-{
-    return narrow_json::from_bjdata(v, true, allow_exceptions);
-}
-
-// BSON can only store numbers as object members
-bytes encode_bson(const json& j)
-{
-    return json::to_bson(json{{"a", j}});
-}
-narrow_json decode_bson(const bytes& v, bool allow_exceptions)
-{
-    const auto result = narrow_json::from_bson(v, true, allow_exceptions);
-    return result.is_discarded() ? result : result.at("a");
-}
-
-bytes encode_bon8(const json& j)
-{
-    return json::to_bon8(j);
-}
-narrow_json decode_bon8(const bytes& v, bool allow_exceptions)
-{
-    return narrow_json::from_bon8(v, true, allow_exceptions);
-}
-
-} // namespace
-
-TEST_CASE("Binary formats with narrow number types")
-{
-    // Numbers that do not fit the number types are handled like the lexer
-    // handles them in JSON text: an integer that fits neither integer type is
-    // stored as a floating-point number, and a finite floating-point number
-    // that overflows number_float_t is rejected with out_of_range.406.
-    struct binary_format
-    {
-        const char* name;
-        bytes (*encode)(const json&);
-        narrow_json (*decode)(const bytes&, bool);
-    };
-
-    const std::vector<binary_format> formats =
-    {
-        {"CBOR", encode_cbor, decode_cbor},
-        {"MessagePack", encode_msgpack, decode_msgpack},
-        {"UBJSON", encode_ubjson, decode_ubjson},
-        {"BJData", encode_bjdata, decode_bjdata},
-        {"BSON", encode_bson, decode_bson},
-        {"BON8", encode_bon8, decode_bon8},
-    };
-
-    for (const auto& format : formats)
-    {
-        const std::string name = format.name;
-        INFO("format := ", name);
-        const auto roundtrip = [&format](const json & j)
-        {
-            return format.decode(format.encode(j), true);
-        };
-
-        // integers that fit keep their type
-        CHECK(roundtrip(json(-5)).is_number_integer());
-        CHECK(roundtrip(json(-5)).get<std::int32_t>() == -5);
-        CHECK(roundtrip(json(3000000000u)).is_number_unsigned());
-        CHECK(roundtrip(json(3000000000u)).get<std::uint32_t>() == 3000000000u);
-
-        // integers that fit neither integer type are stored as float
-        CHECK(roundtrip(json(5000000000u)).is_number_float());
-        CHECK(roundtrip(json(5000000000u)).get<float>() == 5000000000.0f);
-        if (name != "BON8") // BON8 cannot encode integers above INT64_MAX
-        {
-            CHECK(roundtrip(json(10000000000000000000u)).is_number_float());
-            CHECK(roundtrip(json(10000000000000000000u)).get<float>() == 10000000000000000000.0f);
-        }
-        CHECK(roundtrip(json(-3000000000LL)).is_number_float());
-        CHECK(roundtrip(json(-3000000000LL)).get<float>() == -3000000000.0f);
-        CHECK(roundtrip(json(-5000000000LL)).is_number_float());
-        CHECK(roundtrip(json(-5000000000LL)).get<float>() == -5000000000.0f);
-
-        // floating-point numbers that fit
-        CHECK(roundtrip(json(1.5)).get<float>() == 1.5f);
-        const auto just_above_max = std::nextafter(static_cast<double>((std::numeric_limits<float>::max)()),
-                                    std::numeric_limits<double>::infinity());
-        CHECK(roundtrip(json(just_above_max)).get<float>() == (std::numeric_limits<float>::max)());
-
-        // infinity and NaN are passed on
-        CHECK(std::isinf(roundtrip(json(std::numeric_limits<double>::infinity())).get<float>()));
-        CHECK(std::isnan(roundtrip(json(std::numeric_limits<double>::quiet_NaN())).get<float>()));
-
-        // finite floating-point numbers that overflow number_float_t are rejected
-        const std::string message = "[json.exception.out_of_range.406] syntax error while parsing " + name
-                                    + " value: number overflow";
-        CHECK_THROWS_WITH_AS(roundtrip(json(1e300)), message.c_str(), narrow_json::out_of_range&);
-        CHECK_THROWS_WITH_AS(roundtrip(json(-1e300)), message.c_str(), narrow_json::out_of_range&);
-        CHECK(format.decode(format.encode(json(1e300)), false).is_discarded());
-    }
-}

tests/src/unit-cbor.cpp

@@ -3187,8 +3187,7 @@ TEST_CASE("Tagged values")
         // CBOR encodes negative integers as: result = -1 - n
         // For type 0x3B, n is an 8-byte uint64_t. Valid range for n with
         // the default int64_t is [0, INT64_MAX], producing results in [INT64_MIN, -1].
-        // When n > INT64_MAX, the result exceeds int64_t range and is stored
-        // as a floating-point number, as the lexer does for JSON text.
+        // When n > INT64_MAX, the result exceeds int64_t range and is rejected.
 
         SECTION("n = 0 is valid (result = -1)")
         {
@@ -3209,34 +3208,33 @@ TEST_CASE("Tagged values")
             CHECK(result.get<int64_t>() == (std::numeric_limits<int64_t>::min)());
         }
 
-        SECTION("n = INT64_MAX + 1 is stored as float")
+        SECTION("n = INT64_MAX + 1 is rejected (overflow)")
         {
             // n = INT64_MAX + 1 (0x8000000000000000)
-            // result = -1 - n = -9223372036854775809, which exceeds int64_t range;
-            // the nearest double is -9223372036854775808.0
+            // result = -1 - n = -9223372036854775809, which exceeds int64_t range
             const std::vector<uint8_t> input = {0x3B, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
-            const auto result = json::from_cbor(input);
-            CHECK(result.is_number_float());
-            CHECK(result.get<double>() == -9223372036854775808.0);
-            CHECK(result == json::parse("-9223372036854775809"));
+            json _;
+            CHECK_THROWS_WITH_AS(_ = json::from_cbor(input),
+                                 "[json.exception.parse_error.112] parse error at byte 9: syntax error while parsing CBOR value: negative integer overflow",
+                                 json::parse_error);
         }
 
-        SECTION("n = UINT64_MAX is stored as float")
+        SECTION("n = UINT64_MAX is rejected (overflow)")
         {
             // n = UINT64_MAX (0xFFFFFFFFFFFFFFFF)
             // result = -1 - n = -18446744073709551616, which exceeds int64_t range
             const std::vector<uint8_t> input = {0x3B, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF};
-            const auto result = json::from_cbor(input);
-            CHECK(result.is_number_float());
-            CHECK(result.get<double>() == -18446744073709551616.0);
-            CHECK(result == json::parse("-18446744073709551616"));
+            json _;
+            CHECK_THROWS_WITH_AS(_ = json::from_cbor(input),
+                                 "[json.exception.parse_error.112] parse error at byte 9: syntax error while parsing CBOR value: negative integer overflow",
+                                 json::parse_error);
         }
 
-        SECTION("overflow with allow_exceptions=false is not an error")
+        SECTION("overflow with allow_exceptions=false returns discarded")
         {
             const std::vector<uint8_t> input = {0x3B, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
             const auto result = json::from_cbor(input, true, false);
-            CHECK(result.is_number_float());
+            CHECK(result.is_discarded());
         }
     }
 

tests/src/unit-comparison.cpp

@@ -952,3 +952,51 @@ TEST_CASE("containers are compared element by element")
         }
     }
 }
+
+#if JSON_HAS_THREE_WAY_COMPARISON
+// JSON_HAS_CPP_20 (do not remove; see note at top of file)
+TEST_CASE("operator<=> of binary values with a different subtype does not depend on nesting depth")
+{
+    // #5654: std::vector<std::uint8_t>::operator<=>, which the binary type's
+    // own operator<=> uses, ignores the subtype that operator== checks. So a
+    // pair of binary values with the same bytes but a different subtype is
+    // unequal, yet <=>-equivalent - the same inconsistency between == and <=>
+    // that a NaN has. Within the nesting bound, an array compares itself
+    // with std::vector's own operator<=>, which treats an equivalent pair as
+    // undecided and lets the next element decide, same as
+    // std::lexicographical_compare_three_way does. Past the bound,
+    // compare_iteratively<true>() takes over and must classify the pair the
+    // same way, or the result of operator<=> - and of <, which C++20 derives
+    // from it - depends on how deeply the values are nested.
+    const json a = json::array({json::binary({1}, 1), 1});
+    const json b = json::array({json::binary({1}, 2), 2});
+
+    // the root inconsistency: unequal, yet <=>-equivalent
+    CHECK_FALSE(a[0] == b[0]);
+    CHECK((a[0] <=> b[0]) == std::partial_ordering::equivalent); // *NOPAD*
+
+    const auto deep = [](const json & j, const std::size_t depth)
+    {
+        json result = j;
+        for (std::size_t i = 0; i < depth; ++i)
+        {
+            result = json::array({std::move(result)});
+        }
+        return result;
+    };
+
+    // 127 levels stay within nesting_depth_limit() (128); 128 and 200 do not,
+    // and must still agree with the levels that do
+    for (const std::size_t depth : std::vector<std::size_t> {0, 127, 128, 200})
+    {
+        CAPTURE(depth);
+        const json x = deep(a, depth);
+        const json y = deep(b, depth);
+        CHECK((x <=> y) == std::partial_ordering::less); // *NOPAD*
+        CHECK((y <=> x) == std::partial_ordering::greater); // *NOPAD*
+        CHECK(x < y);
+        CHECK(y > x);
+        CHECK_FALSE(y < x);
+    }
+}
+#endif