[Bug c++/108282] New: Disabled template method using requires-clause still viable through requires-expression

[turningtides at outlook dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108282

            Bug ID: 108282
           Summary: Disabled template method using requires-clause still
                    viable through requires-expression
           Product: gcc
           Version: 12.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: turningtides at outlook dot de
  Target Milestone: ---

Created attachment 54185
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=54185&action=edit
source code for gcc 12.2

$ gcc bug.cpp -std=c++20

Log:
bug.cpp: In function ‘int main()’:
bug.cpp:13:33: error: static assertion failed
   13 |     static_assert( TEST <B <C>> == false );
      |                    ~~~~~~~~~~~~~^~~~~~~~
bug.cpp:13:33: note: the comparison reduces to ‘(1 == 0)’
bug.cpp:15:14: error: no matching function for call to ‘B<C>::TT()’
   15 |     B <C>::TT();    // fails to compile!
      |     ~~~~~~~~~^~
bug.cpp:7:24: note: candidate: ‘static void B<AT>::TT() requires  TEST<AT>
[with AT = C]’
    7 |     static inline void TT() noexcept requires ( TEST <AT> );
      |                        ^~
bug.cpp:7:24: note: constraints not satisfied
bug.cpp: In instantiation of ‘static void B<AT>::TT() requires  TEST<AT> [with
AT = C]’:
bug.cpp:15:14:   required from here
bug.cpp:2:9:   required for the satisfaction of ‘TEST<AT>’ [with AT = C]
bug.cpp:2:16:   in requirements  [with T = C]
bug.cpp:2:30: note: the required expression ‘T::TT’ is invalid
    2 | concept TEST = requires { T::TT; };
      |                              ^~
cc1plus: note: set ‘-fconcepts-diagnostics-depth=’ to at least 2 for more
detail