GHC hang

Duncan Coutts duncan.coutts at
Tue Jun 7 06:44:58 EDT 2005

On Tue, 2005-06-07 at 10:52 +0100, Simon Peyton-Jones wrote:
> There is definitely a performance bug somewhere in GHC, and we're
> collecting cases that show it up.  It'd be ideal if you, or someone
> else, could snip out a standalone module or two that demonstrates the
> problem, rather than all of WASH.  If not, we'll try to tackle it
> directly.

I've got a happy grammar that takes ghc many minutes and hundreds of Mb
to typecheck if I leave off the types for all the productions.

If I add types for all the productions it's pretty quick and uses very
little memory.

But I think this is a known issue (it's mentioned in the happy manual)
and not the one you were interested in. Am I right?

I was just suprised that it is such a dramatic effect!


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