[Pitch #3] SE-0293: Extend Property Wrappers to Function and Closure Parameters

[filip-sakel]

@wowbagger

The call site semantics still feels dangerous to me, because the parameter's type ( Wrapped or Projected ) doesn't match the function's type at the parameter's location ( Wrapper ).

If I understand correctly, you think it's dangerous that the types used in the transformed function and the call-site are different –– the former uses the backing storage's type, when the latter uses the wrapped or projected values' types.

I don't see how that is dangerous, though. Could you elaborate on that?

@wowbagger

I wonder if it can be helped by requiring the call site parameters to be annotated with @Wrapper for both wrapped and projected values. E.g.

func foo(@Wrapper value: Wrapped) { /*...*/ }
foo(@Wrapped value: wrapped)
foo(@Wrapped $value: projected)

I don't see how that would help.