Difference between revisions of "GHC/Error messages"
< GHC
Jump to navigation
Jump to search
("Cannot match a monotype with `Foo'") |
|||
Line 1: | Line 1: | ||
GHC error messages and their meaning. |
GHC error messages and their meaning. |
||
− | == " |
+ | == "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. |
This error message occurs when one tries to instantiate a class, but did not import the functions one tries to implement. |
Revision as of 06:22, 15 October 2009
GHC error messages and their meaning.
"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
"Cannot match a monotype with `Foo'"
See this Haskell-Cafe thread.
"Parse error in pattern"
TODO
Example: TODO