diff --git a/libstdc++-v3/include/std/format b/libstdc++-v3/include/std/format index e7e0d2d142b..0d6cc7f6bef 100644 --- a/libstdc++-v3/include/std/format +++ b/libstdc++-v3/include/std/format @@ -4338,6 +4338,9 @@ namespace __format constexpr void basic_format_parse_context<_CharT>::check_dynamic_spec(size_t __id) noexcept { + // _GLIBCXX_RESOLVE_LIB_DEFECTS + // 4142. check_dynamic_spec should require at least one type + static_assert(sizeof...(_Ts) >= 1); // This call enforces the Mandates: condition that _Ts contains valid // types and each type appears at most once. It could be a static_assert // but this way failures give better diagnostics, due to calling the diff --git a/libstdc++-v3/testsuite/std/format/parse_ctx.cc b/libstdc++-v3/testsuite/std/format/parse_ctx.cc index 88ffd77debe..b5dd7cdba78 100644 --- a/libstdc++-v3/testsuite/std/format/parse_ctx.cc +++ b/libstdc++-v3/testsuite/std/format/parse_ctx.cc @@ -491,7 +491,6 @@ test_dynamic_type_check() std::format_parse_context pc("{1}.{2}"); // None of these calls should do anything at runtime, only during consteval: - pc.check_dynamic_spec<>(0); pc.check_dynamic_spec(0); pc.check_dynamic_spec_integral(0); pc.check_dynamic_spec_string(0); diff --git a/libstdc++-v3/testsuite/std/format/parse_ctx_neg.cc b/libstdc++-v3/testsuite/std/format/parse_ctx_neg.cc index f19107c886f..d83fd8c7a7b 100644 --- a/libstdc++-v3/testsuite/std/format/parse_ctx_neg.cc +++ b/libstdc++-v3/testsuite/std/format/parse_ctx_neg.cc @@ -12,8 +12,9 @@ test_invalid() pc.check_dynamic_spec(0); - // For some reason, an empty pack of types is valid: - pc.check_dynamic_spec<>(0); + + // LWG 4142. check_dynamic_spec should require at least one type + pc.check_dynamic_spec<>(0); // { dg-error "here" } pc.check_dynamic_spec(0); // { dg-error "here" } // const void* is allowed, but void* is not @@ -25,6 +26,7 @@ test_invalid() pc.check_dynamic_spec(0); // { dg-error "here" } // std::string_view is allowed, but std::string is not pc.check_dynamic_spec(0); // { dg-error "here" } + // The types in the pack must be unique. pc.check_dynamic_spec(0); // { dg-error "here" } std::wformat_parse_context wpc(L""); @@ -38,3 +40,5 @@ test_invalid() // Each failure above will point to a call to this non-constexpr function: // { dg-error "__invalid_dynamic_spec" "" { target *-*-* } 0 } +// Except the check_dynamic_spec<>(0) one for LWG 4142 which matches this: +// { dg-error "static assertion failed" "" { target *-*-* } 0 }