Expose Substitution's archetype, replacement, and conformances only through getters so we can actually assert invariants about them. To start, require replacement types to be materializable in order to catch cases where the type-checker tries to bind type variables to lvalue or inout types, and require the conformance array to match the number of protocol conformances required by the archetype. This exposes some latent bugs in the test suite I've marked as failures for now:
- test/Constraints/overload.swift was quietly suffering from <rdar://problem/17507421>, but we didn't notice because we never tried to codegen it.
- test/SIL/Parser/array_roundtrip.swift doesn't correctly roundtrip substitutions, which I filed as <rdar://problem/17781140>.
Swift SVN r20418
The need to hide Self from AllArchetypes of a GenericParamList is (almost) defined away by @cc(witness_method); IRGen now knows how to do the right thing for witnesses regardless of their generic signature. Eliminating this special case from the AST allows us to clear up a bunch of ugly hacks that piled up elsewhere to try to accommodate that special case, and makes the prospect of moving IRGen's PolymorphicConvention to interface types more manageable.
We do need an unfortunate hack to suppress emitting associated archetypes of Self when considering an archetype as the polymorphic source for a witness, since we can't actually pass those through the witness CC without breaking ABI compatibility between generic signatures.
Swift SVN r13663
This matches what SIL expects for generic function applications. Add a 'getPrimarySubstitutions' convenience method to ConcreteDeclRef.
Swift SVN r11579
The new ConcreteDeclRef class provides a possibly-speciaized reference
to a declaration, which allows DynamicMemberRefExpr to refer to both
generic and non-generic members. without having to split the AST node.
Swift SVN r7839
