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 | |
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| Blocking | |
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| Operating system | |
| Architecture |