[Bug c++/116239] New: Different function redeclaration in function scope is wrongly accepted

[fchelnokov at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116239

            Bug ID: 116239
           Summary: Different function redeclaration in function scope is
                    wrongly accepted
           Product: gcc
           Version: 14.1.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: fchelnokov at gmail dot com
  Target Milestone: ---

This is an invalid program
```
void f(void);

int main() {
    consteval void f(void); 
}
```
because of function f redeclaration with consteval. It is rejected in Clang and
MSVC, but not in GCC unfortunately. Online demo:
https://gcc.godbolt.org/z/n8x49h8Wa

Expected error: redeclaration 'consteval void f()' differs in 'consteval' from
previous declaration