Don't remove leading and trailing parentheses for closure types in type signature disambiguation

[d-ronnqvist]

Bug/issue #, if applicable: rdar://151311221

Summary

This fixes an issue where DocC would remove leading and trailing parentheses from certain closure types that return an empty tuple in Swift (as opposed to Void). This resulted in unexpected disambiguation suggestions that didn't actually work when applied to the ambiguous link.

Dependencies

None.

Testing

• Define some overloads where one of the parameters is a closure that returns (). For example:

  public func doSomething(with closure: (Int) -> Int) -> Int { 0 }
  public func doSomething(with closure: (Bool) -> ()) -> Int { 0 }
  

• Write an ambiguous link to these overloads:

  /// ``doSomething(with:)``
  public enum Something {}
  

• The suggestions for what disambiguation to add to should suggest -((Bool)->()) instead of -(Bool)->() to indicate that this is a single closure parameter and not a Bool parameter and a separate Void return value (in this example the function doesn't return Void/()).

Checklist

Make sure you check off the following items. If they cannot be completed, provide a reason.

• Added tests
• Ran the ./bin/test script and it succeeded
• [ ] Updated documentation if necessary

[d-ronnqvist]

@swift-ci please test

[patshaughnessy]

Looks good and I was able to verify the (very subtle) fix. Maybe update a comment if you have time.

[d-ronnqvist]

@swift-ci please test