Fix the clang-tidy 22 findings in json_view and its tests

The same changes as on the dump branch, where they were first made, so
that this branch passes clang-tidy on its own.

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

include/nlohmann/detail/view/lookup.hpp

@@ -127,7 +127,7 @@ template<typename SizeType, typename IntegerType>
 SizeType to_index(IntegerType idx) noexcept
 {
     const IntegerType zero = 0;
-    const auto result = static_cast<SizeType>(idx);
+    const auto result = static_cast<SizeType>(idx); // NOLINT(bugprone-signed-char-misuse,cert-str34-c): negative values are mapped below
     return (idx < zero || static_cast<IntegerType>(result) != idx) ? (std::numeric_limits<SizeType>::max)() : result;
 }
 

include/nlohmann/json_view.hpp

@@ -1062,7 +1062,7 @@ using ordered_json_view = basic_json_view<ordered_json>;
 NLOHMANN_JSON_NAMESPACE_END
 
 // tuple protocol for the items of basic_json_view::items() (structured bindings)
-namespace std // NOLINT(cert-dcl58-cpp)
+namespace std // NOLINT(cert-dcl58-cpp,bugprone-std-namespace-modification)
 {
 
 #if defined(__clang__)
@@ -1071,11 +1071,11 @@ namespace std // NOLINT(cert-dcl58-cpp)
     #pragma clang diagnostic ignored "-Wmismatched-tags"
 #endif
 template<typename View>
-class tuple_size<::nlohmann::detail::view::view_item<View>> // NOLINT(cert-dcl58-cpp)
+class tuple_size<::nlohmann::detail::view::view_item<View>> // NOLINT(cert-dcl58-cpp,bugprone-std-namespace-modification)
     : public std::integral_constant<std::size_t, 2> {};
 
 template<std::size_t N, typename View>
-class tuple_element<N, ::nlohmann::detail::view::view_item<View>> // NOLINT(cert-dcl58-cpp)
+class tuple_element<N, ::nlohmann::detail::view::view_item<View>> // NOLINT(cert-dcl58-cpp,bugprone-std-namespace-modification)
 {
   public:
     using type = decltype(std::declval<::nlohmann::detail::view::view_item<View>>().template get<N>());

tests/src/unit-json_view.cpp

@@ -750,7 +750,7 @@ TEST_CASE("json_view element access and iteration")
                 })
         {
             const std::string key(n, 'k');
-            const json_document dk = json_document::parse("{\"" + key + "\":1,\"" + key + "x\":2,\"" + key + "\":3,\"" + key + "\":4}");
+            const json_document dk = json_document::parse("{\"" + key + "\":1,\"" + key + "x\":2,\"" + key + "\":3,\"" + key + "\":4}"); // NOLINT(performance-inefficient-string-concatenation)
             CAPTURE(n)
             CHECK(dk.root()[key].materialize() == 1);
             CHECK(dk.root().at(key).materialize() == 1);
@@ -983,8 +983,8 @@ TEST_CASE("json_view element access and iteration")
             pairs += std::string(key) + "=" + value.materialize().dump() + ";";
         }
         CHECK(pairs == "a=1;b=[true,false];");
-        static_assert(std::tuple_size<json_view::item>::value == 2, "");
+        static_assert(std::tuple_size<json_view::item>::value == 2, "tuple_size of an item is 2");
-        static_assert(std::is_same<std::tuple_element<1, json_view::item>::type, json_view>::value, "");
+        static_assert(std::is_same<std::tuple_element<1, json_view::item>::type, json_view>::value, "the second element of an item is a view");
 #endif
     }
 }
@@ -1177,19 +1177,19 @@ TEST_CASE("json_view values")
             switch (i % 5) // NOLINT(hicpp-multiway-paths-covered)
             {
                 case 0:
-                    std::snprintf(buf.data(), buf.size(), "%.17g", d); // NOLINT(cppcoreguidelines-pro-type-vararg,hicpp-vararg)
+                    static_cast<void>(std::snprintf(buf.data(), buf.size(), "%.17g", d)); // NOLINT(cppcoreguidelines-pro-type-vararg,hicpp-vararg)
                     break;
                 case 1:
-                    std::snprintf(buf.data(), buf.size(), "%.15g", d); // NOLINT(cppcoreguidelines-pro-type-vararg,hicpp-vararg)
+                    static_cast<void>(std::snprintf(buf.data(), buf.size(), "%.15g", d)); // NOLINT(cppcoreguidelines-pro-type-vararg,hicpp-vararg)
                     break;
                 case 2:
-                    std::snprintf(buf.data(), buf.size(), "%.3e", d); // NOLINT(cppcoreguidelines-pro-type-vararg,hicpp-vararg)
+                    static_cast<void>(std::snprintf(buf.data(), buf.size(), "%.3e", d)); // NOLINT(cppcoreguidelines-pro-type-vararg,hicpp-vararg)
                     break;
                 case 3:
-                    std::snprintf(buf.data(), buf.size(), "%.25g", d); // NOLINT(cppcoreguidelines-pro-type-vararg,hicpp-vararg)
+                    static_cast<void>(std::snprintf(buf.data(), buf.size(), "%.25g", d)); // NOLINT(cppcoreguidelines-pro-type-vararg,hicpp-vararg)
                     break;
                 default:
-                    std::snprintf(buf.data(), buf.size(), "%.0f", d); // NOLINT(cppcoreguidelines-pro-type-vararg,hicpp-vararg)
+                    static_cast<void>(std::snprintf(buf.data(), buf.size(), "%.0f", d)); // NOLINT(cppcoreguidelines-pro-type-vararg,hicpp-vararg)
                     break;
             }
             tokens.emplace_back(buf.data());
@@ -1232,7 +1232,7 @@ TEST_CASE("json_view values")
         const json j = json::parse(text);
 
         // user types with from_json, and other types, through basic_json
-        const record r = v.get<record>();
+        const auto r = v.get<record>();
         CHECK(r.name == "widget");
         CHECK(r.count == 3);
         CHECK((v["pair"].get<std::pair<int, std::string>>() == j["pair"].get<std::pair<int, std::string>>()));