#16305: When should -Wmissed-specializations fire? -------------------------------------+------------------------------------- Reporter: crockeea | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.7 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Poor/confusing | Unknown/Multiple error message | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by simonpj): As I read the code it is trying to do this: * `-Wall-missed-specs`: warn about ''any'' overloaded imported functions that cannot be specialised. Usually this means we don't have its RHS. * `-Wmissed-specs`: warn about any overloaded imported functions that can't be specialised, and is transitively called by a chain of imported functions each with an INLINEABLE pragma. For the latter consider {{{ module A where import B foo = f (3::Int) + g (4::Int) module B where f :: Num a => a -> a {-# INLINABLE f #-} f x = h x g x = Num a => a -> a g x = blah h x :: Num a => a -> a h x = blah }}} Then when compiling A, `-Wmissed-specs` is supposed to * Not warn about not-specialising `g`, because `g` didn't have an INLINABLE pragma. * Warn about non-specialising `h` because `f` (which is directly called from A) has a careful `INLINABLE` pragma, but `h` (perhaps due to an oversight) does not. In contrast `-Wall-missed-specs` should warn about both. Does that make sense? Is it what we want? -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/16305#comment:6 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler