Precedence errors are reported for undefined operators
I found a misleading error message.
If I add the import for (<$>), but I forget to save the file
-- other imports -- import Control.Applicative ((<$>)) main = print $ (+1).(+2) <$> Just 5
I get the error
precedence parsing error cannot mix `(.)' [infixr 9] and `(<$>)' [infixl 9] in the same infix expression
which is rather hard to debug, since it makes it seem that the problem is either with Control.Applicative's precedence definitions or that I've somehow imported (<$>) with a different precedence from somewhere else.
It would be nice if it would report instead that (<$>) wasn't defined yet.
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