Permit overloading initializers by external argument labels

Elements Elements Bugs
1

IDE: Visual Studio X/Fire
Version: 10.0.0.2409 (develop)
Target (If relevant): Net
Description:
Swift allows overloading by external argument label. This is already allowed for functions, but not initializers.

Expected Behavior:
Compiles.
Actual Behavior:
“E: Duplicate constructor with same signature “init(other b: Int)” [<file> (<line>)]”
“N: Previous declaration was here [<file> (<line>)]”
Steps:

struct S {
 init(some a: Int) {} // Note Here
 init(other b: Int) {} // Error Here
}
2

Unfortunately this is a limitation of .NET/Java itself. Since these have to map to real constructors, they don’t allow that. I haven’t found a way to solve this.

3

Just brainstorming here, but if you lowered this:

struct S {
 init(some a: Int) { /* code a */ }
 init(other b: Int) { /* code b */}
 init(_ c: Int) { /* code c */ }
}

To something more like this:

struct S {
 enum __S_RemObjLabels {
  case some
  case other
 }
 init(_ x: Int, _ l: __RemObjsLabels) {
  switch l {
  case .some:
    /* code a */
  case .other:
    /* code b */
  }
 }
 init(_ c: Int) { /* code c */ }
}

Would that work?

However, until labeled inits are supported, I request the errors changed to be:

struct S {
 init(some a: Int) {} // E: Labeled (initializers|constructors) unsupported on `.NET`
 init(other b: Int) {} // E: Labeled (initializers|constructors) unsupported on `.NET`
}

As they are not redeclarations, they are simply both declaring something unsupported on the .NET platform.

4

Thanks, logged as bugs://82748

5

bugs://82748 got closed with status fixed.