[Bug c++/128501] New: internal compiler error: in insert, at cp/module.cc

[0599jiangyc at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=128501

            Bug ID: 128501
           Summary: internal compiler error: in insert, at cp/module.cc
           Product: gcc
           Version: 17.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: 0599jiangyc at gmail dot com
  Target Milestone: ---

The following code:
```cpp
export module foo;
namespace ns { typedef int T; }
constexpr int f () { using ns::T; return 0; }
```

Resulted in this output:
```
<source>:1:8: internal compiler error: in insert, at cp/module.cc:5218
```

Trunk reproducer (`-std=c++20 -fmodules`): https://godbolt.org/z/j5z71fs6h