[Haskell-cafe] strange behavior of GHC 7.8.2

Kazu Yamamoto (=?iso-2022-jp?B?GyRCOzNLXE9CSScbKEI=?=) kazu at iij.ad.jp
Tue Jul 8 01:41:03 UTC 2014


Christiaan,

Thank you for your reply.

> I think GHC always picks the package with the highest version
> number, and does _not_ resolve to the package that gives the least
> amount of type errors.  The "Loading package transformers-0.3.0.0"
> is not there due to your own use of transformers.  It's being loaded
> because it is a dependency of 'ghc-7.8.2'.

I have reached the same conclusion. "-v" reveals this:

----
% ghci -v A.hs -package ghc                          
...
hiding package transformers-0.3.0.0 to avoid conflict with later version transformers-0.4.1.0
...
----

> Also note that this behaviour is not specific to 7.8.*, it is also
> present in 7.6.3.  The only thing you can to with both version of
> transformers installed is to just do:
>> ghci -package ghc -hide-package transformers-0.4.1.0 A.hs

Thanks.

"ghci A.hs -package ghc -package transformers-0.3.0.0" works for me.

--Kazu


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