Open Radar

 
Summary:

Attempting to specialize a generic type where a parameter T is constrained to protocol MyProtocol fails when passing in MyProtocol as the Type satisfying the constraint.

Steps to Reproduce:
protocol  MyType {
 
}
 
struct Thing : MyType {
}
 
 
struct Foo<T, U : MyType> {
    let one:T
    let two:U
}
 
struct Bar<T> {
    let one:T
    let two:MyType
}
 
let theThing = Thing()
 
let expected: Foo<Int, Thing> = Foo(one: 0, two: theThing)
let nice:Bar<Int> = Bar(one: 1, two: theThing)
// I think it could be great if the following line were basically equivalent to the line immediately above.
let potentiallyGreat: Foo<Int, MyType> = Foo(one: 2, two: theThing)

Expected Results:
The last line, `let potentiallyGreat: Foo<Int, MyType> = Foo(one: 2, two: theThing)`, should compile and be equivalent to `let nice:Bar<Int> = Bar(one: 1, two: theThing)`

Actual Results:
Compilation fails “Generic parameter ‘U’ cannot be bound to non-@objc protocol type ‘MyType’”