From 75efea25b2b805da489558d6d8bb854e37c4c744 Mon Sep 17 00:00:00 2001
From: Niels Lohmann <mail@nlohmann.me>
Date: Mon, 19 Oct 2026 22:06:50 +0200
Subject: [PATCH] Skip the deleted-overload checks of json_view on MSVC 2015

MSVC 2015 does not treat selecting a deleted function in decltype as a
substitution failure, so is_detected reports the deleted
parse/parse_copy/accept/read(ptr, len) overloads as callable and the
static_asserts in "integer arguments do not compile" fail (AppVeyor
VS2015 jobs). Calling them still fails to compile there. Guard the
negative checks as unit-delete_deprecated_functions.cpp does.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
---
 tests/src/unit-json_view.cpp | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

diff --git a/tests/src/unit-json_view.cpp b/tests/src/unit-json_view.cpp
index 6e91200b4..ea3be303a 100644
--- a/tests/src/unit-json_view.cpp
+++ b/tests/src/unit-json_view.cpp
@@ -511,27 +511,31 @@ TEST_CASE("json_view")
     {
         using nlohmann::detail::is_detected;
 
-        // a length is not a flag: parse(ptr, len) would convert len to
-        // allow_exceptions and read ptr as a C string, which need not end
         static_assert(is_detected<parse_call_t, const char*, bool>::value, "parse(ptr, bool) is valid");
         static_assert(is_detected<parse_call_t, const char*, bool, bool, bool>::value, "parse(ptr, bool, bool, bool) is valid");
         static_assert(is_detected<parse_call_t, const char*, const char*>::value, "parse(first, last) is valid");
         static_assert(is_detected<parse_call_t, const char*, const char*, bool>::value, "parse(first, last, bool) is valid");
+        static_assert(is_detected<parse_copy_call_t, const char*, bool>::value, "parse_copy(ptr, bool) is valid");
+        static_assert(is_detected<accept_call_t, const char*, bool>::value, "accept(ptr, bool) is valid");
+        static_assert(is_detected<read_call_t, const char*, bool>::value, "read(ptr, bool) is valid");
+
+        // a length is not a flag: parse(ptr, len) would convert len to
+        // allow_exceptions and read ptr as a C string, which need not end
+        //
+        // MSVC 2015 does not treat selecting a deleted function in decltype as
+        // a substitution failure, so it detects the deleted overloads as
+        // callable; calling them still fails to compile
+#if !(defined(_MSC_VER) && _MSC_VER < 1910)
         static_assert(!is_detected<parse_call_t, const char*, std::size_t>::value, "parse(ptr, len) must not compile");
         static_assert(!is_detected<parse_call_t, const char*, int>::value, "parse(ptr, int) must not compile");
         static_assert(!is_detected<parse_call_t, const char*, char>::value, "parse(ptr, char) must not compile");
         static_assert(!is_detected<parse_call_t, const char*, std::size_t, bool>::value, "parse(ptr, len, bool) must not compile");
         static_assert(!is_detected<parse_call_t, const std::string&, std::size_t>::value, "parse(string, len) must not compile");
         static_assert(!is_detected<parse_call_t, const std::vector<char>&, std::size_t>::value, "parse(vector, len) must not compile");
-
-        static_assert(is_detected<parse_copy_call_t, const char*, bool>::value, "parse_copy(ptr, bool) is valid");
         static_assert(!is_detected<parse_copy_call_t, const char*, std::size_t>::value, "parse_copy(ptr, len) must not compile");
-
-        static_assert(is_detected<accept_call_t, const char*, bool>::value, "accept(ptr, bool) is valid");
         static_assert(!is_detected<accept_call_t, const char*, std::size_t>::value, "accept(ptr, len) must not compile");
-
-        static_assert(is_detected<read_call_t, const char*, bool>::value, "read(ptr, bool) is valid");
         static_assert(!is_detected<read_call_t, const char*, std::size_t>::value, "read(ptr, len) must not compile");
+#endif
 
         // json_view has no conversion to bool: unlike basic_json's, it would
         // mean "exists", not "is not null"; use is_discarded()