https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93239
--- Comment #2 from joseph at codesourcery dot com <joseph at codesourcery dot com> --- I'd be concerned about trouble when code processing statements tries to deal with context that doesn't exist outside of functions. Consider a statement expression containing a function definition (does that count as a nested function?), statement expressions containing declarations, possibly with extern, possibly not (how do those interact with file-scope declarations?), statement expressions containing _Atomic operations (see the sort of issues we had in bug 65345, though that was fixed), statement expressions containing __local__ declarations and goto. It would be necessary to go through language features systematically, especially declarations and language features that try to create declarations internally, to ensure they behave sensibly inside statement expressions at file scope - and to test all the same features in old-style parameter declarations to ensure declarations from those features don't get mixed up in the parameter declaration handling. (I concur that unevaluated statement expressions *should* be allowed at file scope, but think such a change would need pretty extensive test coverage of language features that are likely to be risky in such a context.)
