The use of ASTContext-allocated arrays to store the members of nominal
type declarations and the extensions thereof is an
abomination. Instead, introduce the notion of an "iterable"
declaration context, which keeps track of the declarations within that
context (stored as a singly-linked list) and allows iteration over
them. When a member is added, it will also make sure that the member
goes into the lookup table for its context immediately.
This eliminates a ton of wasted memory when we have to reallocate the
members arrays for types and extensions, and moves us toward a much
more sane model. The only functionality change here is that the Clang
importer no longer puts subscript declarations into the wrong class,
nor does it nested a C struct within another C struct.
Swift SVN r16572
If an enum has no cases with payloads, make it implicitly Equatable and Hashable, and derive default implementations of '==' and 'hashValue'. Insert the derived '==' into module context wrapped in a new DerivedFileUnit kind, and arrange for it to be codegenned with the deriving EnumDecl by adding a 'DerivedOperatorDecls' array to NominalTypeDecls that gets visited at SILGen time.
Swift SVN r14471
For derivable protocols, such as RawRepresentable on raw-typed enums, when checking the conformance, create a conforming decl if an explicit decl wasn't found. Refactor the conformance derivation for toRaw/fromRaw to be driven by conformance checking in this way.
Swift SVN r8930
If an enum has a valid raw type, synthesize a RawType associated type along with fromRaw and toRaw methods.
An implicit conformance to RawRepresentable is not yet set up. This synthesis may need to be done earlier in order for the names to be available during type-checking of definitions in the enum too.
Swift SVN r8890
