Compiler replaces =sink for =copy

[planetis-m]

What happened?

Explicitly calling =sink doesn't work. It's rewritten as copy.

proc main =
  var a = "abc"
  var b = "de"
  `=sink`(a, b)
  echo a

main()

Nim Version

Nim Compiler Version 1.7.3 [Linux: amd64]
Compiled at 2022-10-15
Copyright (c) 2006-2022 by Andreas Rumpf

git hash: 0510a2b
active boot switches: -d:release --gc:markAndSweep

Current Standard Output Logs

# --expandArc:main

var
  a
  b_cursor
try:
  a = "abc"
  b_cursor = "de"
  `=copy`(a, b_cursor)
  echo [a]
finally:
  `=destroy`(a)

Expected Standard Output Logs

No response

Possible Solution

No response

Additional Information

std/isolation is affected from this bug because in:

proc `=sink`*[T](dest: var Isolated[T]; src: Isolated[T]) {.inline.} =
  # delegate to value's sink operation
  `=sink`(dest.value, src.value)

It's replaced by =copy!

[beef331]

You dont call =sink you do move so a = move b and dest.value = move src.value. Though given these are string literals copying the cursor is the same as a move afaik.

[Araq]

@beef331 In this case move cannot be used.