is duplicated by:

• SR-8944 Ambiguous use in constrained protocol extension

relates to:

• SR-7126 Swift 4.1 protocol overlap ambiguous property

Issue Description:

Sorry if my summary is incorrect.

We have code that looks like this:

class C {}

extension C {
    var integer: Int { return 1 }
}

protocol P {
    var integer: Int { get }
}

extension P where Self: C {
    var anotherInteger: Int { return self.integer }
}

This compiles with "Apple Swift version 4.1 (swiftlang-902.0.48 clang-902.0.37.1)".
With swift-DEVELOPMENT-SNAPSHOT-2018-04-12-a.xctoolchain this gives error:

bug.swift:13:38: error: ambiguous use of 'integer'
    var anotherInteger: Int { return self.integer }
                                     ^
bug.swift:4:9: note: found this candidate
    var integer: Int { return 1 }
        ^
bug.swift:8:9: note: found this candidate
    var integer: Int { get }
        ^

The ambiguity can be resolved by making sure that self is of type C:

var anotherInteger: Int { return (self as C).integer }

Is this ambiguity error the expected behavior?