Re: [Haskell-cafe] ghc -O2 and HUnit weirdness

* Roman Cheplyaka [2011-01-07 01:42:24+0200]

* Jürgen Doser [2011-01-07 00:18:09+0100]

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El jue, 06-01-2011 a las 16:41 -0400, Joey Hess escribió:

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So, the problem seems to be that ghc -O2 somehow optimises the static assertBool _ True away, in what seems to be a bad way. Remove the -O2 and the test fails as expected. Presumably, although I have not verified, less static boolean values would not trigger the optimisation. Is this a ghc or HUnit bug?

(Versions: 6.12.1, 1.2.2.1)

Looks like a GHC bug.

Works with -fno-state-hack.

Here's a particular quote from the GHC source [1] Technically, this isn't quite right, because (f True) `seq` 1 should diverge, but it'll converge if we eta-expand f. Nevertheless, we do so; it improves some programs significantly, and increasing convergence isn't a bad thing. As it turns out in the case of HUnit, it may be a bad thing. [1]: http://www.haskell.org/ghc/docs/6.12.3/html/libraries/ghc-6.12.3/src/CoreAri... -- Roman I. Cheplyaka :: http://ro-che.info/ Don't worry what people think, they don't do it very often.