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 _)) = Truemistakenly 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 |