ClangImporter::lookupTypeDecl allows a Clang type declaration to be
imported by Clang name instead of by Swift name. Now that we're using
Clang names in mangled names, that's exactly what we need to
reconstruct an AST type from a mangled name.
Also:
- Handle @compatibility_alias in ClangImporter::lookupTypeDecl
- Print errors when type reconstruction fails in swift-ide-test
- Add an extra test for RemoteAST
This makes them consistent no matter what shenanigans are pulled by
the importer, particularly NS_ENUM vs. NS_OPTIONS and NS_SWIFT_NAME.
The 'NSErrorDomain' API note /nearly/ works with this, but the
synthesized error struct is still mangled as a Swift declaration,
which means it's not rename-stable. See follow-up commits.
The main place where this still falls down is NS_STRING_ENUM: when
this is applied, a typedef is imported as a unique struct, but without
it it's just a typealias for the underlying type. There's also still a
problem with synthesized conformances, which have a module mangled
into the witness table symbol even though that symbol is linkonce_odr.
rdar://problem/31616162
