add warning for prefix negate operator and flag to replace it with negative numeric literals
This is tracking a few things relating to the notion that Haskell's single prefix operator, "
-", should not exist and "
-1" should parse as a single token anyway. See http://thread.gmane.org/gmane.comp.lang.haskell.glasgow.user/11954
If there is a LANGUAGE option for this, what should it be called; and what should the ghc flags be called? Should turning off prefix negation and turning on negative numeric literals be separately controllable? This sort of question (exactly what should be implemented) is probably half the difficulty here.