swift

30015dc8 - [ConstraintSystem] Don't attempt dynamic member lookup on invalid base

[ConstraintSystem] Don't attempt dynamic member lookup on invalid base If `subscript(dynamicMember:)` is unviable because it's either an instance method referenced on type or static method referenced on an instance of type, attempting dynamic member lookup would be incorrect since it's unclear what is intended. Resolves: rdar://problem/48994658 (cherry picked from commit cd07652f223782e8be9f2152915412822c5592a6)