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
In Sema, give derived '==' definitions the module's DerivedFileUnit as their decl context instead of the more general Module, and give it a backreference to the nominal type for which it was derived.
In SILGen, visit the derived global decls associated with Clang-imported enums, and give them shared linkage. Part of fixing <rdar://problem/16264703>.
Swift SVN r14875
This names the implicit argument "oldValue". Whether we keep implicit arguments or not
is a subject of debate, tracked by rdar://16268361.
Swift SVN r14819
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
