Nim/tests/effects/tgcsafe2.nim

discard """
  errormsg: '''type mismatch: got (proc (s: string){.locks: 0.})'''
  line: 11
"""
#5620
var res = ""

proc takeCallback(foo: (proc(s: string) {.gcsafe.})) =
  foo "string"

takeCallback(proc (s: string) =
  res &= s & "abc")