[Bug c++/104670] New: ICE when using decltype of a lambda returning a struct inside of a struct

[krzysio.kurek at wp dot pl via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104670

            Bug ID: 104670
           Summary: ICE when using decltype of a lambda returning a struct
                    inside of a struct
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: krzysio.kurek at wp dot pl
  Target Milestone: ---

Created attachment 52502
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=52502&action=edit
-freport-bug output

GCC ICEs when compiling the following piece of code:

struct foo {
    decltype([] { return (struct {
        int fn() {}
    }){}; }) bar;
};

Compiled with `-std=c++20`
Past stable releases of GCC report "confused by earlier errors, bailing out"
without crashing instead.