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October 2005

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Undefined variable bug
by John Tromp 27 Feb '07

27 Feb '07

I just found out that I can circumvent the problem by adding a line import Char to my loaded file. regards, -john

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[Hugs-bugs] existentials
by Ross Paterson 29 Oct '05

29 Oct '05

Iavor Diatchki writes: > It appears that Hugs (20050909) does not deal correctly with > existentials and multi-parameter type classes: > > > class C a b where > > f :: a -> b > > > > data T b = forall a. C a b => T a > > > > test (T a) = f a > > Hugs accepts this program, inferring the following type for 'test': > Main> :t test > test :: C _5 a => T b -> a > Main> :t test (undefined :: T Char) > test undefined :: C (T Char) a => a The same bug shows without multi-parameter type classes: Hugs accepts data T = forall a. C a test (C x) = toInteger x Now fixed in CVS.

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