https://gcc.gnu.org/g:9450fb705caca3df0f968e66768eec6e38458a9f
commit r16-2076-g9450fb705caca3df0f968e66768eec6e38458a9f Author: Jonathan Wakely <jwak...@redhat.com> Date: Mon Jul 7 11:32:48 2025 +0100 libstdc++: Use template keyword in __mapping_of alias template This is needed to fix an error with Clang 19: include/c++/16.0.0/mdspan:512:30: error: use 'template' keyword to treat 'mapping' as a dependent template name 512 | is_same_v<typename _Layout::mapping<typename _Mapping::extents_type>, | ^ libstdc++-v3/ChangeLog: * include/std/mdspan (__mapping_of): Add template keyword. Diff: --- libstdc++-v3/include/std/mdspan | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/libstdc++-v3/include/std/mdspan b/libstdc++-v3/include/std/mdspan index c72a64094b73..4a06fb2d3a86 100644 --- a/libstdc++-v3/include/std/mdspan +++ b/libstdc++-v3/include/std/mdspan @@ -509,7 +509,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION template<typename _Layout, typename _Mapping> concept __mapping_of = - is_same_v<typename _Layout::mapping<typename _Mapping::extents_type>, + is_same_v<typename _Layout::template mapping<typename _Mapping::extents_type>, _Mapping>; template<typename _Mapping>