swift234

SILGen: Properly lower types of ObjC generic methods dispatched off AnyObject.

When an ObjC generic method is found by AnyObject dispatch, we don't have any type information to bind generic parameter dependencies. Sema expands these generic parameters to their upper bounds in an AnyObject dispatch. However, SILGen was still lowering the type of a dynamic method invocation from the method's formal type, expecting its generic parameters to be bound by substitutions provided from a call. Lower dynamic method calls using the substituted type from the AST instead to avoid this. Fixes rdar://problem/26380562.