swift

53f32e6a - [5.1] IRGen: Save the current generic signature before mangling an opaque type decl (#27022)

[5.1] IRGen: Save the current generic signature before mangling an opaque type decl (#27022) It comes with its own generic signature. Explanation: We crash generating the mangling for an opaque type decl. Scope of Issue: Affects code that uses opaque result types. The compiler will crash. Risk: Low. We cache and restore a generic signature before mangling opaque type decls which will introduce their own generic signature. Review: Joe Groff Testing: Swift regression test added. rdar://54824119