[Haskell-cafe] What is the consensus about -fwarn-unused-do-bind ?

[Ivan Lazar Miljenovic]

Roel van Dijk <vandijk.roel at gmail.com> writes:

> Can anyone provide an example of an error that is prevented by this
> warning? When exactly is it dangerous to ignore a monadic function's
> return value?

See Neil's original rationale in the bug report:
http://hackage.haskell.org/trac/ghc/ticket/3263

Short version: using something like mapM but disregarding the result
(rather than using mapM_) can sometimes lead to space leaks.

-- 
Ivan Lazar Miljenovic
Ivan.Miljenovic at gmail.com
IvanMiljenovic.wordpress.com