Difference between revisions of "GHC/Error messages"

Revision as of 06:20, 15 October 2009

GHC error messages and their meaning.

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

See this Haskell-Cafe thread.

TODO

Example: TODO

@@ Line 1: / Line 1: @@
 GHC error messages and their meaning.
-== "Parse error in pattern" ==
-TODO
-Example: TODO
 == "Foo' is not a (visible) method of class `Bar'" ==
@@ Line 21: / Line 14: @@
     (==) a b = True
 </haskell>
+== "Cannot match a monotype with `Foo'" ==
+See [http://www.haskell.org/pipermail/haskell-cafe/2009-October/067806.html this] Haskell-Cafe thread.
+== "Parse error in pattern" ==
+TODO
+Example: TODO