Ricardo Wurmus <rek...@elephly.net> writes: > Mark H Weaver <m...@netris.org> writes: > >> I suppose if one reads the error message literally: >> >> Control/Monad/Trans/Resource/Internal.hs:302:10: error: >> • Could not deduce (MonadBase IO (Strict.StateT s m)) >> arising from the superclasses of an instance declaration >> from the context: MonadResource m >> bound by the instance declaration >> at Control/Monad/Trans/Resource/Internal.hs:302:10-63 >> • In the instance declaration for >> ‘MonadResource (Strict.StateT s m)’ >> >> "Could not deduce" might be interpreted to include the case where we >> failed for lack of sufficient memory. They might have written the code >> to catch any error at all, including out of memory errors, and report >> the failure with this error message. > > I think that’s a misunderstanding. The cause for the error is earlier > when it complains that some packages depend on different versions of the > “transformers” package. “StateT” is a monad transformer. > > I think that “ghc-pkg” fails, which leads to some other version of the > transformers package (maybe a default included with GHC) to be used. In > the case where ghc-pkg does not fail (as on my laptop) the proper > version is used, so there are no problems finding the expected > instances.
Ah, okay, that sounds plausible. I confess that my previous message was somewhat rushed, without much investigation or thought behind it. Apologies for the noise. Regards, Mark