Hem hem ... I should never try to write anything sensible before putting my thick glasses. -w does not turn ON all warnings, but turns them OFF, so my previous comment regarding swapping its definition with -Wall is just nonsense. Sorry for the noise. Still, do you think there could be room for a -Wsuspicious that would be defined as current -Wall, and for a more intuitive meaning for -Wall : turns on really all warnings ? Paul> Indeed, that's not part of -Wall. Paul> http://www.haskell.org/ghc/docs/7.0.4/html/users_guide/options-sanity.html Paul> Am I the only one who assumed so far that Wall turned on all Paul> existing warnings ? Paul> From the doc : Paul> -Wall: Turns on all warning options that indicate potentially Paul> suspicious code. The warnings that are not enabled by -Wall Paul> are -fwarn-tabs, -fwarn-incomplete-record-updates, -fwarn-monomorphism-restriction, -fwarn-unused-do-bind, Paul> and -fwarn-implicit-prelude. Paul> -w: Turns off all warnings, including the standard ones and those Paul> that -Wall doesn't enable. Paul> If there were no backward compatibility issues, I'd prefer to just Paul> see -w and -Wall swaped. -w would mean "We let the GHC team decide Paul> what subset of warnings they really want us to observe", and -Wall Paul> would mean "We really want them all". -- Paul