[ ghc-Bugs-1309795 ] Control.Exception.assert broken with -O

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Bugs item #1309795, was opened at 2005-09-30 14:20
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Category: libraries/base
Group: 6.4.1
Status: Open
Resolution: None
Priority: 5
Submitted By: Fergus Henderson (fergus)
Assigned to: Nobody/Anonymous (nobody)
Summary: Control.Exception.assert broken with -O

Initial Comment:
According to the ghc documentation
(section 4.9 "optimization" and section 7.8 "assertions" in
the user guide, and the documentation for Control.Exception
in the hierarchical libraries guide),
assertions should be checked unless explicitly disabled
with
"-fignore-asserts", and the "-O" option should have no
effect on them.

But in ghc version 6.4.1.20050801, "-O" seems to also
have the
effect of disabling assertions:

   bash$ cat Test.hs
   import Control.Exception
   main = print (assert False (42::Int))

   bash$ ghc -O Test.hs && ./a.out
   42

This undocumented behaviour is an egregious violation
of the
principle of least surprise.





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