https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97517
Bug ID: 97517 Summary: _Up = 'nullptr_type' not supported by simple_type_specifier'nullptr_type' not supported by direct_abstract_declarator Product: gcc Version: 10.2.1 Status: UNCONFIRMED Keywords: diagnostic Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: redi at gcc dot gnu.org Target Milestone: --- template<typename> struct Trait { static constexpr bool value = false; }; template<typename T> concept Concept = Trait<T>::value; static_assert( Concept<decltype(nullptr)> ); Compiled with -std=c++20 gives: c.C:5:16: error: static assertion failed 5 | static_assert( Concept<decltype(nullptr)> ); | ^~~~~~~~~~~~~~~~~~~~~~~~~~ c.C:5:16: note: constraints not satisfied c.C:3:30: required by the constraints of ‘template<class T> concept Concept’ c.C:3:50: note: the expression ‘Trait< <template-parameter-1-1> >::value [with <template-parameter-1-1> = ‘nullptr_type’ not supported by simple_type_specifier‘nullptr_type’ not supported by direct_abstract_declarator]’ evaluated to ‘false’ 3 | template<typename T> concept Concept = Trait<T>::value; | ^~~~~