swift

e3cbf770 - [Opaque result types] Fix mangling issues with opaque result types.

[Opaque result types] Fix mangling issues with opaque result types. Fix a trio of issues involving mangling for opaque result types: * Symbolic references to opaque type descriptors are not substitutions * Mangle protocol extension contexts correctly * Mangle generic arguments for opaque result types of generic functions The (de-)serialization of generic parameter lists for opaque type declarations is important for the last bullet, to ensure that the mangling of generic arguments of opaque result types works across module boundaries. Fixes the rest of rdar://problem/50038754.