If the replacement type was a function type or protocol-constrained type (e.g. 'Class & Proto) and the existing type had a postfix ? or !, we weren't wrapping the replacement in parens. This would result in an incorrect/ambiguous new type. This patch wraps the replacement in parens if it contains an & or ->, the existing type has a trailing ? or !.
Resolves rdar://problem/32082269.
Based on recommendations in SE-0160, there are two migration workflows:
- Conservative: Maintain @objc visibility that was inferred in Swift 3
by adding @objc to all declarations that were implicitily visible to
the Objective-C runtime. This is invoked in the migrator by adding the
-migrate-keep-objc-visibility flag.
- Minimal: Only declarations that must be visible to Objective-C based
on their uses (or in cases like dynamic vars) are migrated.
rdar://problem/31876357
This handles optionality changes and type rewrites in function param and return types and constructor param and failability types.
Resolves rdar://problem/31766010
