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.)
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