[Bug c++/97052] New: Internal compiler error with substitution failure in template parameter list of concept declaration

[david at doublewise dot net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97052

            Bug ID: 97052
           Summary: Internal compiler error with substitution failure in
                    template parameter list of concept declaration
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: david at doublewise dot net
  Target Milestone: ---

The following code

```
template<typename T, typename U = typename T::type>
concept foo = true;

constexpr bool f(foo auto) {
        return false;
}

constexpr bool f(int) {
        return true;
}

static_assert(f(0));
```

fails to compile with

```
<source>:4:18: internal compiler error: in dependent_type_p, at cp/pt.c:26440

    4 | constexpr bool f(foo auto) {

      |                  ^~~

Please submit a full bug report,

with preprocessed source if appropriate.

See <https://gcc.gnu.org/bugs/> for instructions.

Compiler returned: 1
```



See it live: https://godbolt.org/z/EjEePo