Wrong exception raised wrapped in finally in closure iterator; Regression in devel/version-2-2

[nitely]

Nim Version

Nim Compiler Version 2.3.1 [Linux: amd64]
Compiled at 2025-09-25
Copyright (c) 2006-2025 by Andreas Rumpf

git hash: 9f74712ec6ec346f8f1366c10f752d0a9aa85a70
active boot switches: -d:release

Nim Compiler Version 2.2.5 [Linux: amd64]
Compiled at 2025-10-02
Copyright (c) 2006-2025 by Andreas Rumpf

active boot switches: -d:release

git hash: cfe163795f3a8ac8ecf11dc0ab788a3758b2a32e

Description

This raises ValueError in 2.2.5 and devel. Works fine in Nim 2.2.4 and 2.0.16/2.0.17.

proc p() =
  iterator p_1073741828(): int {.
      closure, gcsafe, raises: [].} =
    var closureSucceeded_1073741827 = true
    try:
      try:
        try:
          yield 0
          raise newException(ValueError, "value error")
        except ValueError:
          raise newException(IOError, "io error")
      finally:
        yield 0
    except IOError as exc:
      closureSucceeded_1073741827 = false
      echo "io raised"
    finally:
      if closureSucceeded_1073741827:
        discard
  
  var internalClosure: iterator(): int = p_1073741828
  var internalClosure2: iterator(): int = p_1073741828

  while true:
    if not internalClosure.finished():
      discard internalClosure()
    if not internalClosure2.finished():
      discard internalClosure2()
    if internalClosure.finished() and internalClosure2.finished():
      break

p()
echo "ok"

Current Output

io raised
Error: unhandled exception: value error [ValueError]

Expected Output

io raised
io raised
ok

Known Workarounds

No response

Additional Information

No response

[narimiran]

Git bisect shows #25030 as the first problematic commit. cc @yglukhov