Function name with proceeding the underline sign is not highlighted.

[vonavi]

Here is a little example, where function name at the last line is not highlighted (its face is default instead of haskell-definition-face):

isEmpty :: [Int] -> Bool
isEmpty [] = True
isEmpty _  = False

Best regards,
Vladimir.

[fice-t]

@gracjan This is due to this commit ff84682

Another issue that commit causes is that the function name gets font-locked too soon:

is_empty$

When your cursor is where the $ is, then the is_ is font-locked, but the empty is not.

This also affects a function ending in an underscore. For example, mapM_ doesn't get font-locked anymore:

mapM_ :: Monad m => (a -> m b) -> [a] -> m ()
mapM_ f= foldr ((>>) . f) (return ())