Provide warning for when RecordWildCards LHS {..} doesn't bind anything.
Given simple code like
{-# LANGUAGE RecordWildCards #-}
module M (foo) where
data D = D { d1 :: Int, d2 :: Int }
foo :: D -> Int -> Int
foo D{..} x = x + 5
There is no way that I know of to get GHC to warn us that the D{..}
in foo
is not binding anything at all.
This is very common after refactoring (perhaps foo
looked like foo D{..} x = x + d1 + 5
before) and would be great to be able to get a warning about.
Of course it's not dead code as it still forces D
to WHNF but if we're using RecordWildCards
syntax then it's probably not what we were going for.
Trac metadata
Trac field | Value |
---|---|
Version | 8.6.2 |
Type | FeatureRequest |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | Compiler |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | |
Operating system | |
Architecture |