GHC/Error messages
From HaskellWiki
(Difference between revisions)
(→"Foo' is not a (visible) method of class `Bar'") |
(→"Foo' is not a (visible) method of class `Bar'") |
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This error message occurs when one tries to instantiate a class, but did not import the functions one tries to implement. | This error message occurs when one tries to instantiate a class, but did not import the functions one tries to implement. | ||
| - | Example: | + | Example: |
| + | <haskell> | ||
| + | import Prelude hiding ((==)) | ||
| + | data Foo = Foo | ||
| + | instance Eq Foo where | ||
| + | (==) a b = True | ||
| + | </haskell> | ||
Revision as of 17:07, 9 October 2009
GHC error messages and their meaning.
1 "Parse error in pattern"
TODO
Example: TODO
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.
Example:
import Prelude hiding ((==)) data Foo = Foo instance Eq Foo where (==) a b = True
