hokein added a comment. In D130511#3677423 <https://reviews.llvm.org/D130511#3677423>, @sammccall wrote:
> My main concern here is that this might reject valid code (and if it doesn't, > it's not obvious why). > It does look like C++ forbids the cases I can come up with (e.g. trying to > provide a definition for `::Foo` is rejected by clang with "definition or > redeclaration of Foo cannot name the global scope). > But I'd be way more comfortable if we could connect the specific guard rules > here with spec language. The qualified declarator is tricky (it was forbidden until https://cplusplus.github.io/CWG/issues/482.html). The closest thing I can find in the standard is basic.lookup.qual.general <https://eel.is/c++draft/basic.lookup.qual.general>: > If a name, template-id, or decltype-specifier is followed by a ::, it shall > designate a namespace, class, enumeration, or dependent type, and the :: is > never interpreted as a complete nested-name-specifier. IIUC, this rule forbids the parses `X::Y ::Z;` and `X ::Y::Z;` (because in the declarator we have a complete `::` nested-name-specifier). > If we can't do this rigorously and merely are trying to encourage the > *common* parse, then we should do it in soft disambig. > > I'd like to think about this some more, do you know what part of the spec > says that `x ::y` is invalid if x is e.g. a typedef for `int`? I didn't try to find it harder, I guess it is probably in the qualified-name-look-up section. Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D130511/new/ https://reviews.llvm.org/D130511 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
