[Bug c++/126423] New: ICE with expansion statement (that is empty) with return and no return after and auto

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126423

            Bug ID: 126423
           Summary: ICE with expansion statement (that is empty) with
                    return and no return after and auto
           Product: gcc
           Version: 17.0
            Status: UNCONFIRMED
          Keywords: c++26, ice-on-valid-code
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: pinskia at gcc dot gnu.org
  Target Milestone: ---

Take:
```
auto f() {
  template for (auto x : {}) {
    return x;
  }
}
```

This causes an ICE:
<source>: In function 'auto f()':
<source>:5:1: warning: control reaches end of non-void function [-Wreturn-type]
    5 | }
      | ^
during RTL pass: expand
<source>:1:6: internal compiler error: in make_decl_rtl, at varasm.cc:1487
    1 | auto f() {
      |      ^