relates to:

• SR-11166 Confusing fixit when protocol requirement has masked type name

Issue Description:

Have a module Foo with a public protocol FooProtocol, and a class FooClass:

class FooClass {

}

public protocol FooProtocol: class {

{{ func protocolFunc(_ foo: FooClass)}}

{{}}}

Implement a class in MyModule, where the module also implements its own FooClass:

class FooClass {

}

class MyClass: FooProtocol {

{{ func protocolFunc(_ foo: FooClass) {}}

{{ }}}

{{}}}

Xcode complains that you haven't implemented the protocol function, even though you have. It helpfully points out that the signature of the function you implemented is identical to the one that it wants. It even offers to add the 'missing' function, and if you do it complains that you now have duplicate functions.

The solution is to explicitly namespace FooClass - Foo.FooClass. However, a compiler warning hinting that this was the problem would eliminate many head/desk incidents trying to figure out why a protocol was missing, when it was the exact same protocol Xcode added as a 'fix'.