Type error when sink added to parameters about nim

[beef331]

Issue seems to be sink tuple drops sink afaik so you probably want:

type
  A = object
  B = object
  C = object
  
proc foo[A, B, C: tuple](input: sink A; adding: sink B; output: var C) =
  output = (input[0], adding[0], adding[1])

let combine = foo[(A,), (B, C), (A, B, C)]
echo typeof(combine)

[Nycto]

Unfortunately, it doesn't look like that will work for my specific use case. I had simplified my code for the sake of repro, but what I'm doing is passing the proc reference to a function, more like this:

type
  A = object
  B = object
  C = object
  
proc foo[X, Y, Z: tuple](input: sink X; adding: sink Y; output: var Z) =
  output = (input[0], adding[0], adding[1])

proc useFoo(fooArg: proc (existing: sink (A, ), newValues: sink (B, C), output: var (A, B, C)) {.nimcall.}) =
  discard

useFoo(foo)

This still fails:

/usercode/in.nim(12, 7) Error: type mismatch
Expression: useFoo(foo)
  [1] foo: proc (input: sink X: tuple, adding: sink Y: tuple, output: var Z: tuple)

Expected one of (first mismatch at [position]):
[1] proc useFoo(fooArg: proc (existing: sink (A,); newValues: sink (B, C);
                          output: var (A, B, C)) {.nimcall.})
  expression 'foo' is of type: proc (input: sink X: tuple, adding: sink Y: tuple, output: var Z: tuple)