[Bug c++/125330] New: [17 Regression] Explicit object parameter not available in the scope of trailing requires expression

[pilarlatiesa at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=125330

            Bug ID: 125330
           Summary: [17 Regression] Explicit object parameter not
                    available in the scope of trailing requires expression
           Product: gcc
           Version: 17.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: pilarlatiesa at gmail dot com
  Target Milestone: ---

I've just noticed on Compiler Explorer that the following (valid) snipped is
rejected by trunk. It is accepted by 14, 15, and 16.

```
struct T
{
  template<typename Self>
  void foo(this Self const &x) requires requires { x.bar(); }
    { x.bar(); }
};
```

The reported error is:
<source>:5:52: error: 'x' was not declared in this scope
    5 |   void foo(this Self const &x) requires requires { x.bar(); }
      |