Pattern Synonyms in Typeclasses
data A t where
AX :: A X
AY :: A Y
AZ :: A Z
class HasX a where
data pattern X :: a X
instance HasX A where
data pattern X = AX
d :: A t -> String
d = \case
X -> ""
AY -> ""
AZ -> ""
The above example should compile and emit no warnings with -fwarn-incomplete-patterns. Would require #8779 (closed)
Trac metadata
Trac field | Value |
---|---|
Version | 8.0.1 |
Type | FeatureRequest |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | Compiler |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | |
Operating system | |
Architecture |