*** emerge --noreplace --oneshot --nospinner dev-haskell/mtl ***
001594 Calculating dependencies  ..... ..... ..... ... done!
001595 
001596 !!! Error: the dev-lang/ghc-bin package conflicts with another package;
001597 !!!        the two packages cannot be installed on the same system together.
001598 !!!        Please use 'emerge --pretend' to determine blockers.
001599 
001600 For more information about Blocked Packages, please refer to the following
001601 section of the Gentoo Linux x86 Handbook (architecture is irrelevant):
001602 
001603 http://www.gentoo.org/doc/en/handbook/handbook-x86.xml?full=1#blocked
001604 
001605 *** process completed ***