* [cxx-interop] Add Hashable conformance to imported enums
Previously, imported enums only conformed to RawRepresentable and Equatable,
so they could not be used as members of a Set or keys of a Dictionary.
This patch adds Hashable conformance to give them that ability,
as well as some test cases to clarify the expected behavior.
Existing test cases are updated to reflect this new conformance.
rdar://129713687
Make sure nested namespaces are added to the SwiftLookupTable when they are declared in a non-canonical redecl of the parent namespace.
This was blocking C++ interop adoption in SwiftCompilerSources.
If possible, add imported members to the StructDecl's LookupTable rather than adding them directly as members. This will fix the issues with ordering that #39436 poorly attempted to solve during IRGen.
This also allows us to break out most of the test changes from #39436.
The pattern:
struct X { friend struct Y; }; struct Y {};
is fairly common. But before this commit we would crash while attempting
to add "Y" as a child of "X". This commit simply checks if the child
record is a declaration or definition. If the former, it bails (and the
"child" record will be imported where it's defined).
Rather than skipping non-definitions, we should just check whether we've
already seen this decl. This not only fixes the specific problem with
class templates but also is a more general fix for other sub decls.
