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GHC/Error messages

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m ("Foo' is not a (visible) method of class `Bar'")
("Cannot match a monotype with `Foo'")
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GHC error messages and their meaning.
 
GHC error messages and their meaning.
 
== "Parse error in pattern" ==
 
 
TODO
 
 
Example: TODO
 
 
   
 
== "Foo' is not a (visible) method of class `Bar'" ==
 
== "Foo' is not a (visible) method of class `Bar'" ==
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(==) a b = True
 
(==) a b = True
 
</haskell>
 
</haskell>
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  +
== "Cannot match a monotype with `Foo'" ==
  +
  +
See [http://www.haskell.org/pipermail/haskell-cafe/2009-October/067806.html this] Haskell-Cafe thread.
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== "Parse error in pattern" ==
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  +
TODO
  +
  +
Example: TODO

Revision as of 06:20, 15 October 2009

GHC error messages and their meaning.

1 "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.

Example:

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

2 "Cannot match a monotype with `Foo'"

See this Haskell-Cafe thread.


3 "Parse error in pattern"

TODO

Example: TODO