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7033 :: quit() returning bool in else branch?

• Akito (orginal) [2020-11-05T00:16:20+01:00] view original

  I've encountered something weird. Not sure if it is a bug or if I'm missing something.

  Works:

  if not init():
      quit(1)
    else:
      ok()
  Run

  Does not work:

  if init():
      ok()
    else:
      quit(1)
  Run

  Telling me:

  Error: expression 'quit(1)' is of type 'bool' and has to be used (or discarded);

  Even though,

  quit never returns

  as stated here.

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• solo989 (orginal) [2020-11-05T00:48:59+01:00] view original

  I assume your ok function returns a bool. This is the case of a slightly misleading error message. All branches of an if stmt have to return the same type so the quit branch implicitly returns a bool. If your ok function returned nothing or was discarded the error message would disappear.

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• solo989 (orginal) [2020-11-05T00:59:59+01:00] view original

  I looked into it a bit further.

  Your ok function returns bool and is {.discardable.} correct?

  The type of an if stmt is determined by it's first branch.

  If the first branch is quit(1) the type is void and ok() {.discardable.} is compatible.

  However if the first branch is ok() it determines the type to be bool which is a little strange because if you replaced

  quit(1)
  Run

  with

  echo "quit"
  Run

  the type would be void and the program would work.

  So this may be a bug with how quit() interacts with discardable.

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• solo989 (orginal) [2020-11-05T01:05:14+01:00] view original

  You can work around it with

  if init():
    discard ok()
  else:
    quit(1)
  Run

  or

  if init():
    ok()
  else:
    quit(1)
    discard
  Run

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• Akito (orginal) [2020-11-05T11:36:46+01:00] view original

  Your ok function returns bool and is {.discardable.} correct?

  The type of an if stmt is determined by it's first branch.

  Wow. You are precisely correct. I did not know about the type thing for an if statement.

  So this may be a bug with how quit() interacts with discardable.

  Although, this is nonetheless a slight bug, after all?

  Anyway, thanks for your help! I'm learning every single day... :)

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