#12106: Wrong type inferenced for locally defined function -------------------------------------+------------------------------------- Reporter: syd | Owner: Type: bug | Status: closed Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 Resolution: invalid | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by rwbarton): * status: new => closed * resolution: => invalid Comment: The [http://stackoverflow.com/questions/32496864/what-is-the-monomorphism- restriction monomorphism restriction] applies to `myPrint`, so its inferred type cannot be `Show a => a -> IO ()`. It has nothing to do with the absense of a `Show` instance for `B` (as you can check by adding that instance). In GHCi the monomorphism restriction is disabled by default (as of a recent version of GHC). You can also turn it off for a module with `{-# LANGUAGE NoMonomorphismRestriction #-}`. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12106#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler