Mirror of forum.nim-lang.org

2768 :: Is this a bug in the nim compiler?

• myankles (orginal) [2017-01-29T01:51:54+01:00] view original

  I'm a noob in the Nim community, so apologies if I'm posting in the wrong forum.

  I discovered a snippet of code which behaves differently depending on whether or not release mode is used for compilation. I'm wondering if this is a compiler bug or if I'm doing something wrong.

  Here is source, bug.nim:

  
  proc bug() : void =
      var x = 0
      try:
          inc x
          raise new(Exception)
      except Exception:
          echo x
  
  bug()
  Run

  Here's what happens:

  
  $ nim c bug.nim
  ...
  $ ./bug
  1
  $ nim c -d:release bug.nim
  ...
  $ ./bug
  0
  $ nim --version
  Nim Compiler Version 0.16.0 (2017-01-08) [MacOSX: amd64]
  Copyright (c) 2006-2017 by Andreas Rumpf
  
  git hash: 5947403e84ba44397b35f93f9d327c76e794210f
  active boot switches: -d:release
  Run

  Please observe that the code prints 1 when using normal compilation and 0 when using release mode. Is this expected? Am I doing something wrong? Thanks for your help!

---

• Araq (orginal) [2017-01-29T02:06:37+01:00] view original

  A bug. Workaround: use x = x + 1 instead of inc x here.

---

• myankles (orginal) [2017-01-29T02:10:19+01:00] view original

  Thank you, Araq!

---

• myankles (orginal) [2017-01-29T02:12:31+01:00] view original

  Should I post a bug on github?

---

• Araq (orginal) [2017-01-29T02:13:36+01:00] view original

  Of course.

---