[SR-13086] Code completion for KeyPath-based @dynamicMemberLookup

[belkadan]

Previous ID	SR-13086
Radar	None
Original Reporter	@belkadan
Type	Improvement

Additional Detail from JIRA

Votes	0
Component/s	CodeCompletion
Labels	Improvement
Assignee	None
Priority	Medium

md5: e4a61b5548653332509db6b87bfff95c

Issue Description:

SE-0252 added support for key-path-based dynamic member lookup, but code completion doesn't show any of those members.

@dynamicMemberLookup
struct PointlessWrapper<T> {
  var value: T

  subscript<U>(dynamicMember keyPath: WritableKeyPath<T, U>) -> PointlessWrapper <U> {
    return PointlessWrapper<U>(value: self.value[keyPath: keyPath])
  }
}

struct Point {
  var x, y: Double
}

let wrapper = PointlessWrapper<Point>(value: Point(x: 0, y: 0))
let wrapperX = wrapper. // complete here

[xAlien95]

It is currently working. Could you re-check @belkadan?

The only case in which it fails to provide code completion is for tuple members: e.g. if value is (foo: Int, bar: String), then it won't suggest .0, .1, .bar and .baz, which is what I'm currently looking for.

@rintaro, should I open a new issue as Bug instead of Improvement for that specific case?

Edit: there are more cases in which it fails, e.g. if you have static subscript(dynamicMember:).

[CraigSiemens]

I just ran into the same issue that @xAlien95 is describing with tuples.

It appears that it works correctly with structs like in the example in the original post, but autocompletion and syntax highlighting doesnt correctly handle tuple key paths with dynamicMemberLookup.