Potential Bug in SE-0029 (Remove implicit tuple splat behavior from function applications)

David_Sweeris · 2016-04-18T20:45:43.000Z

I was updating some old code to Swift 2.2, and came across an unexpected tuple splat warning. This code is all you need to generate the deprecation warning:
public class Value<T> {
    public typealias Element = T
    public typealias Ret = T
}
public class Expression<A, R> : Value<R> {
    public typealias Arg = A
    public var args: Arg! = nil
    public subscript(arg: Arg) -> Value<Ret> { return self }
}
public class Op<A, R> : Expression<A, R> {
    public typealias OpType = Arg -> Value<R>
    public let op: OpType
    init(op: OpType) {
        self.op = op
        super.init()
    }
}
public class BinaryOp<A1, A2, R> : Op<(A1, A2), R> {
    override init(op: OpType) {
        super.init(op: op)
    }
    override public subscript(x: Arg) -> Value<Ret> {
        return op(x) //Warning: Passing 2 arguments to a callee as a single tuple value is deprecated
    }
}

I don’t understand why the compiler thinks I’m trying to splat the tuple… `op` takes one argument of type `Arg` and I’m giving it one argument of type `Arg`. In the case of a `BinaryOp`, `Arg` does happen to be a tuple, but the proposal (https://github.com/apple/swift-evolution/blob/master/proposals/0029-remove-implicit-tuple-splat.md\) specifically says "it does not propose removing the ability to pass tuples as values to functions”.

Am I missing something, or have I found a bug in Swift 2.2?

- Dave Sweeris

(PS, Sorry if this is the wrong list… I’m not sure where potential bug reports go.)

jrose · 2016-04-18T21:25:47.000Z

Good catch. Seems like an issue with the diagnostic. Can you file a bug at bugs.swift.org?

Jordan

···

On Apr 18, 2016, at 13:45, David Sweeris via swift-dev <swift-dev@swift.org> wrote:

I was updating some old code to Swift 2.2, and came across an unexpected tuple splat warning. This code is all you need to generate the deprecation warning:
public class Value<T> {
    public typealias Element = T
    public typealias Ret = T
}
public class Expression<A, R> : Value<R> {
    public typealias Arg = A
    public var args: Arg! = nil
    public subscript(arg: Arg) -> Value<Ret> { return self }
}
public class Op<A, R> : Expression<A, R> {
    public typealias OpType = Arg -> Value<R>
    public let op: OpType
    init(op: OpType) {
        self.op = op
        super.init()
    }
}
public class BinaryOp<A1, A2, R> : Op<(A1, A2), R> {
    override init(op: OpType) {
        super.init(op: op)
    }
    override public subscript(x: Arg) -> Value<Ret> {
        return op(x) //Warning: Passing 2 arguments to a callee as a single tuple value is deprecated
    }
}

I don’t understand why the compiler thinks I’m trying to splat the tuple… `op` takes one argument of type `Arg` and I’m giving it one argument of type `Arg`. In the case of a `BinaryOp`, `Arg` does happen to be a tuple, but the proposal (https://github.com/apple/swift-evolution/blob/master/proposals/0029-remove-implicit-tuple-splat.md\) specifically says "it does not propose removing the ability to pass tuples as values to functions”.

Am I missing something, or have I found a bug in Swift 2.2?

- Dave Sweeris

(PS, Sorry if this is the wrong list… I’m not sure where potential bug reports go.)
_______________________________________________
swift-dev mailing list
swift-dev@swift.org
https://lists.swift.org/mailman/listinfo/swift-dev

David_Sweeris · 2016-04-18T22:31:50.000Z

Sure

···

On Apr 18, 2016, at 4:25 PM, Jordan Rose <jordan_rose@apple.com> wrote:

Good catch. Seems like an issue with the diagnostic. Can you file a bug at bugs.swift.org <Issues · apple/swift · GitHub?

Jordan

On Apr 18, 2016, at 13:45, David Sweeris via swift-dev <swift-dev@swift.org <mailto:swift-dev@swift.org>> wrote:

I was updating some old code to Swift 2.2, and came across an unexpected tuple splat warning. This code is all you need to generate the deprecation warning:
public class Value<T> {
    public typealias Element = T
    public typealias Ret = T
}
public class Expression<A, R> : Value<R> {
    public typealias Arg = A
    public var args: Arg! = nil
    public subscript(arg: Arg) -> Value<Ret> { return self }
}
public class Op<A, R> : Expression<A, R> {
    public typealias OpType = Arg -> Value<R>
    public let op: OpType
    init(op: OpType) {
        self.op = op
        super.init()
    }
}
public class BinaryOp<A1, A2, R> : Op<(A1, A2), R> {
    override init(op: OpType) {
        super.init(op: op)
    }
    override public subscript(x: Arg) -> Value<Ret> {
        return op(x) //Warning: Passing 2 arguments to a callee as a single tuple value is deprecated
    }
}

I don’t understand why the compiler thinks I’m trying to splat the tuple… `op` takes one argument of type `Arg` and I’m giving it one argument of type `Arg`. In the case of a `BinaryOp`, `Arg` does happen to be a tuple, but the proposal (https://github.com/apple/swift-evolution/blob/master/proposals/0029-remove-implicit-tuple-splat.md\) specifically says "it does not propose removing the ability to pass tuples as values to functions”.

Am I missing something, or have I found a bug in Swift 2.2?

- Dave Sweeris

(PS, Sorry if this is the wrong list… I’m not sure where potential bug reports go.)
_______________________________________________
swift-dev mailing list
swift-dev@swift.org <mailto:swift-dev@swift.org>
https://lists.swift.org/mailman/listinfo/swift-dev

David_Sweeris · 2016-04-18T22:53:58.000Z

Done. [SR-1261] Swift incorrectly identifies passing a tuple to a function as a tuple splat · Issue #43869 · apple/swift · GitHub

Out of curiosity, what happens if I click “Assign to me”? I think it’d be kinda fun to try to fix the glitch, but I don’t have the faintest idea where to start.

- Dave Sweeris

···

On Apr 18, 2016, at 5:31 PM, David Sweeris via swift-dev <swift-dev@swift.org> wrote:

Sure

On Apr 18, 2016, at 4:25 PM, Jordan Rose <jordan_rose@apple.com <mailto:jordan_rose@apple.com>> wrote:

Good catch. Seems like an issue with the diagnostic. Can you file a bug at bugs.swift.org <Issues · apple/swift · GitHub?

Jordan

On Apr 18, 2016, at 13:45, David Sweeris via swift-dev <swift-dev@swift.org <mailto:swift-dev@swift.org>> wrote:

I was updating some old code to Swift 2.2, and came across an unexpected tuple splat warning. This code is all you need to generate the deprecation warning:
public class Value<T> {
    public typealias Element = T
    public typealias Ret = T
}
public class Expression<A, R> : Value<R> {
    public typealias Arg = A
    public var args: Arg! = nil
    public subscript(arg: Arg) -> Value<Ret> { return self }
}
public class Op<A, R> : Expression<A, R> {
    public typealias OpType = Arg -> Value<R>
    public let op: OpType
    init(op: OpType) {
        self.op = op
        super.init()
    }
}
public class BinaryOp<A1, A2, R> : Op<(A1, A2), R> {
    override init(op: OpType) {
        super.init(op: op)
    }
    override public subscript(x: Arg) -> Value<Ret> {
        return op(x) //Warning: Passing 2 arguments to a callee as a single tuple value is deprecated
    }
}

I don’t understand why the compiler thinks I’m trying to splat the tuple… `op` takes one argument of type `Arg` and I’m giving it one argument of type `Arg`. In the case of a `BinaryOp`, `Arg` does happen to be a tuple, but the proposal (https://github.com/apple/swift-evolution/blob/master/proposals/0029-remove-implicit-tuple-splat.md\) specifically says "it does not propose removing the ability to pass tuples as values to functions”.

Am I missing something, or have I found a bug in Swift 2.2?

- Dave Sweeris

(PS, Sorry if this is the wrong list… I’m not sure where potential bug reports go.)
_______________________________________________
swift-dev mailing list
swift-dev@swift.org <mailto:swift-dev@swift.org>
https://lists.swift.org/mailman/listinfo/swift-dev

_______________________________________________
swift-dev mailing list
swift-dev@swift.org
https://lists.swift.org/mailman/listinfo/swift-dev

Austin · 2016-04-18T22:55:35.000Z

Nothing much happens, except other people who see the ticket will know someone else is working on it and not start on it themselves. You can always release the ticket if you decide you can't or don't want to work on it anymore.

Austin

···

On Apr 18, 2016, at 3:53 PM, David Sweeris via swift-dev <swift-dev@swift.org> wrote:

Done. [SR-1261] Swift incorrectly identifies passing a tuple to a function as a tuple splat · Issue #43869 · apple/swift · GitHub

Out of curiosity, what happens if I click “Assign to me”? I think it’d be kinda fun to try to fix the glitch, but I don’t have the faintest idea where to start.

- Dave Sweeris

On Apr 18, 2016, at 5:31 PM, David Sweeris via swift-dev <swift-dev@swift.org <mailto:swift-dev@swift.org>> wrote:

Sure

On Apr 18, 2016, at 4:25 PM, Jordan Rose <jordan_rose@apple.com <mailto:jordan_rose@apple.com>> wrote:

Good catch. Seems like an issue with the diagnostic. Can you file a bug at bugs.swift.org <Issues · apple/swift · GitHub?

Jordan

On Apr 18, 2016, at 13:45, David Sweeris via swift-dev <swift-dev@swift.org <mailto:swift-dev@swift.org>> wrote:

I was updating some old code to Swift 2.2, and came across an unexpected tuple splat warning. This code is all you need to generate the deprecation warning:
public class Value<T> {
    public typealias Element = T
    public typealias Ret = T
}
public class Expression<A, R> : Value<R> {
    public typealias Arg = A
    public var args: Arg! = nil
    public subscript(arg: Arg) -> Value<Ret> { return self }
}
public class Op<A, R> : Expression<A, R> {
    public typealias OpType = Arg -> Value<R>
    public let op: OpType
    init(op: OpType) {
        self.op = op
        super.init()
    }
}
public class BinaryOp<A1, A2, R> : Op<(A1, A2), R> {
    override init(op: OpType) {
        super.init(op: op)
    }
    override public subscript(x: Arg) -> Value<Ret> {
        return op(x) //Warning: Passing 2 arguments to a callee as a single tuple value is deprecated
    }
}

I don’t understand why the compiler thinks I’m trying to splat the tuple… `op` takes one argument of type `Arg` and I’m giving it one argument of type `Arg`. In the case of a `BinaryOp`, `Arg` does happen to be a tuple, but the proposal (https://github.com/apple/swift-evolution/blob/master/proposals/0029-remove-implicit-tuple-splat.md\) specifically says "it does not propose removing the ability to pass tuples as values to functions”.

Am I missing something, or have I found a bug in Swift 2.2?

- Dave Sweeris

(PS, Sorry if this is the wrong list… I’m not sure where potential bug reports go.)
_______________________________________________
swift-dev mailing list
swift-dev@swift.org <mailto:swift-dev@swift.org>
https://lists.swift.org/mailman/listinfo/swift-dev

_______________________________________________
swift-dev mailing list
swift-dev@swift.org <mailto:swift-dev@swift.org>
https://lists.swift.org/mailman/listinfo/swift-dev

_______________________________________________
swift-dev mailing list
swift-dev@swift.org
https://lists.swift.org/mailman/listinfo/swift-dev

David_Sweeris · 2016-04-18T23:01:39.000Z

Oh, ok, thanks. I’ll be sure to *not* click on it until I figure out how LLVM works! :-D

- Dave Sweeris

···

On Apr 18, 2016, at 5:55 PM, Austin Zheng <austinzheng@gmail.com> wrote:

Nothing much happens, except other people who see the ticket will know someone else is working on it and not start on it themselves. You can always release the ticket if you decide you can't or don't want to work on it anymore.

Austin

On Apr 18, 2016, at 3:53 PM, David Sweeris via swift-dev <swift-dev@swift.org <mailto:swift-dev@swift.org>> wrote:

Done. [SR-1261] Swift incorrectly identifies passing a tuple to a function as a tuple splat · Issue #43869 · apple/swift · GitHub

Out of curiosity, what happens if I click “Assign to me”? I think it’d be kinda fun to try to fix the glitch, but I don’t have the faintest idea where to start.

- Dave Sweeris

On Apr 18, 2016, at 5:31 PM, David Sweeris via swift-dev <swift-dev@swift.org <mailto:swift-dev@swift.org>> wrote:

Sure

On Apr 18, 2016, at 4:25 PM, Jordan Rose <jordan_rose@apple.com <mailto:jordan_rose@apple.com>> wrote:

Good catch. Seems like an issue with the diagnostic. Can you file a bug at bugs.swift.org <Issues · apple/swift · GitHub?

Jordan

On Apr 18, 2016, at 13:45, David Sweeris via swift-dev <swift-dev@swift.org <mailto:swift-dev@swift.org>> wrote:

I was updating some old code to Swift 2.2, and came across an unexpected tuple splat warning. This code is all you need to generate the deprecation warning:
public class Value<T> {
    public typealias Element = T
    public typealias Ret = T
}
public class Expression<A, R> : Value<R> {
    public typealias Arg = A
    public var args: Arg! = nil
    public subscript(arg: Arg) -> Value<Ret> { return self }
}
public class Op<A, R> : Expression<A, R> {
    public typealias OpType = Arg -> Value<R>
    public let op: OpType
    init(op: OpType) {
        self.op = op
        super.init()
    }
}
public class BinaryOp<A1, A2, R> : Op<(A1, A2), R> {
    override init(op: OpType) {
        super.init(op: op)
    }
    override public subscript(x: Arg) -> Value<Ret> {
        return op(x) //Warning: Passing 2 arguments to a callee as a single tuple value is deprecated
    }
}

I don’t understand why the compiler thinks I’m trying to splat the tuple… `op` takes one argument of type `Arg` and I’m giving it one argument of type `Arg`. In the case of a `BinaryOp`, `Arg` does happen to be a tuple, but the proposal (https://github.com/apple/swift-evolution/blob/master/proposals/0029-remove-implicit-tuple-splat.md\) specifically says "it does not propose removing the ability to pass tuples as values to functions”.

Am I missing something, or have I found a bug in Swift 2.2?

- Dave Sweeris

(PS, Sorry if this is the wrong list… I’m not sure where potential bug reports go.)
_______________________________________________
swift-dev mailing list
swift-dev@swift.org <mailto:swift-dev@swift.org>
https://lists.swift.org/mailman/listinfo/swift-dev

_______________________________________________
swift-dev mailing list
swift-dev@swift.org <mailto:swift-dev@swift.org>
https://lists.swift.org/mailman/listinfo/swift-dev

_______________________________________________
swift-dev mailing list
swift-dev@swift.org <mailto:swift-dev@swift.org>
https://lists.swift.org/mailman/listinfo/swift-dev