Open Radar

 
Summary:
In Swift, you can correctly overload a function based upon the type signature of a closure parameter, but that doesn’t work when the parameter is an object.

Steps to Reproduce:
Attempt to compile the following code:
class Realm {
    func f(block: (() -> Void)) {
        block()
    }

    func f(block: ((Realm) -> Void)) {
        block(self)
    }
}

Realm().f {
    println("no args")
}

Realm().f { realm in
    println("realm: \(realm)")
}

Expected Results:
The code compiles

Actual Results:
At the second invocation of Realm().f, there’s an “Ambiguous use of ‘f’” compiler error

Regression:
N/A

Notes:
This overloading works if the second definition of f were as follows:
func f(block: ((Int) -> Void)) {
        block(0)
    }