[Bug c++/108179] New: [11/12 regression] ICE related to template template parameters in tsubst, at cp/pt.cc:15782

[s at stu dot scot]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108179

            Bug ID: 108179
           Summary: [11/12 regression] ICE related to template template
                    parameters in tsubst, at cp/pt.cc:15782
           Product: gcc
           Version: 12.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: s at stu dot scot
  Target Milestone: ---

Created attachment 54126
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=54126&action=edit
Bug report from -freport-bug

The following code produces an internal compiler error on all g++ 11 and 12
versions I tried. This is the most minimal example I could come up with. It
compiles fine under g++ 10 and clang.

```
template <class T, T X, template <T> class F>
struct Foo {};

template <class T0, class T1, T1 X, template <T1> class F>
void f(Foo<T1, X, F>) {}
```

Works in:
* g++-10 (Ubuntu 10.4.0-4ubuntu1~22.04) 10.4.0
Doesn't work in:
* g++-11 (Ubuntu 11.3.0-1ubuntu1~22.04) 11.3.0
* g++-12 (Ubuntu 12.1.0-2ubuntu1~22.04) 12.1.0
* x86-64 gcc 12.2 on compiler explorer: https://godbolt.org/z/EMncPKcea