This commit also changes how specialized types are being emitted. Previously we
would not emitthe detailed member information in the specialized type itself,
and instead rely on the fact that it was present in the unspecialized type,
however, this wold prevent us from emitting any bound generic members, so we're
now emitting the members in both variants of the type.
This uncovered a with type aliases that this commit also addresses: Because we
don't canonicalize types prior to caching in order to preserve type sugar,
alternative representations of recursive types (with one or more levels of
recursion unfolded) could create potential infinite chains of types. This is
addressed by checking whether a sugared type has an already emitted canonical
representation first, and if yes, creating a typedef node pointing directly to
it.
The donwside of doing this is that it can lead to the disappearnce of type
aliases definitions when they are used as parameters in bound generic
types. However, we still preserve that a type was `MyClass<MyAlias>`. We just
might have a typedef pointing director from `MyClass<MyAlias>` ->
`MyClass<CanonicalType>`.
rdar://144315592
