[project @ 2003-06-20 11:14:18 by simonpj]
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Fix a small quantification bug
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We were quantifying over too few type variables, because fdPredsOfInsts was
being too eager to discard predicates. This only affects rather obscure
programs. Here's the one Iavor found:
class C a b where f :: a -> b
g x = fst (f x)
We want to get the type
g :: forall a b c. C a (b,c) => a -> b
but GHC 6.0 bogusly gets
g :: forall a b. C a (b,()) => a -> b
A test is in should_compile/tc168