#10560: -f and -O options interact in non-obvious, order dependent ways -------------------------------------+------------------------------------- Reporter: bgamari | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Incorrect | Unknown/Multiple warning at compile-time | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Revisions: -------------------------------------+------------------------------------- Comment (by rwbarton): The parts of this I feel strongly about are * GHC should never warn about a command line that is valid. It will just cause too many headaches for build systems. The effects of options should be clearly documented and then GHC should do what the user asks without any second-guessing. If a combination of options really doesn't make sense, then it should be an error and not a warning. * `-ffoo -fno-foo` and `-fno-foo -ffoo` (and `-O1 -O0`, etc.) should be valid with the last flag taking priority, as is the case today. I'm not really qualified to comment on how obvious the current behavior of `-fno-specialise -O1` is (it's obvious to me, but I've had the dubious pleasure of reading through DynFlags.hs on many occasions). I also can't think of a use case where the rule suggested in comment:2 "process all `-O` flags before all `-f` flags" would prevent one from doing something useful. So it sounds OK to me. But no warnings please! -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10560#comment:15 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler