Completeness of View Patterns With a Complete Set of Output Patterns
For example, the code
{-# OPTIONS_GHC -Wall #-}
{-# LANGUAGE ViewPatterns #-}
f :: Maybe a -> Bool
f (id->Nothing) = False
f (id->(Just _)) = True
mistakenly returns the warning
warning: [-Wincomplete-patterns]
Pattern match(es) are non-exhaustive
In an equation for ‘f’: Patterns not matched: _
|
4 | f (id->Nothing) = False
| ^^^^^^^^^^^^^^^^^^^^^^^^...
Trac metadata
Trac field | Value |
---|---|
Version | 8.6.2 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | Compiler |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | alanz, bgamari |
Operating system | |
Architecture |