Warn if a pattern guard obviates all others
The following code, when compiled with -Wall
, gives no warnings:
module Main where
main :: IO ()
main = print $ foo (10 :: Int)
where
foo x
| True = (20 :: Int)
| x == 10 = (30 :: Int)
I would expect that since the pattern guard | True
obviates the following guards, that it would warn about unreachable code. There was a bug in my code today which I tracked down to a code transposition that would have been easily spotted with such a warning.
Trac metadata
Trac field | Value |
---|---|
Version | 7.6.3 |
Type | FeatureRequest |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | Compiler |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | |
Operating system | |
Architecture |