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GHC/Error messages

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("is not a (visible) method of class")
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Latest revision as of 13:49, 3 December 2009

GHC error messages and their meaning.


[edit] 1 "`foo' is not applied to enough type arguments"


Example: TODO

[edit] 2 "`foo' is not a (visible) method of class `Bar'"

This error message occurs when one tries to instantiate a class, but did not import the functions one tries to implement.


import Prelude hiding ((==))
data Foo = Foo
instance Eq Foo where 
    (==) a b = True

[edit] 3 "Cannot match a monotype with `Foo'"

See this Haskell-Cafe thread.

[edit] 4 "Parse error in pattern"


Example: TODO