This should be mapM_ and 'ghc -Wall' spots this problem since 6.12.
The compiler (7.04) doesn't tell me anything about it.
Henning> It seems that it is no longer part of -Wall. Indeed, that's not part of -Wall. http://www.haskell.org/ghc/docs/7.0.4/html/users_guide/options-sanity.html Am I the only one who assumed so far that Wall turned on all existing warnings ?
From the doc :
-Wall: Turns on all warning options that indicate potentially suspicious code. The warnings that are not enabled by -Wall are -fwarn-tabs, -fwarn-incomplete-record-updates, -fwarn-monomorphism-restriction, -fwarn-unused-do-bind, and -fwarn-implicit-prelude. -w: Turns off all warnings, including the standard ones and those that -Wall doesn't enable. If there were no backward compatibility issues, I'd prefer to just see -w and -Wall swaped. -w would mean "We let the GHC team decide what subset of warnings they really want us to observe", and -Wall would mean "We really want them all". -- Paul