Resolving dependencies...
cabal: Could not resolve dependencies:
next goal: pipes (user goal)
rejecting: pipes-4.2.0, pipes-4.1.9, pipes-4.1.8, pipes-4.1.7, pipes-4.1.6,
pipes-4.1.5, pipes-4.1.4, pipes-4.1.3, pipes-4.1.2, pipes-4.1.1 (constraint
from user target requires ==4.1.0)
trying: pipes-4.1.0
next goal: mtl (dependency of pipes-4.1.0)
rejecting: mtl-2.2.1, mtl-2.2.0.1, mtl-2.2 (conflict: pipes => mtl>=2.0.1.0 &&
<2.2)
trying: mtl-2.1.3.1
trying: transformers-compat-0.5.1.4:-two
trying: transformers-compat-0.5.1.4:+mtl
trying: transformers-compat-0.5.1.4:-three
next goal: transformers (dependency of pipes-4.1.0)
rejecting: transformers-0.5.2.0/installed-0.5..., transformers-0.5.2.0,
transformers-0.5.1.0, transformers-0.5.0.1, transformers-0.5.0.0,
transformers-0.4.3.0, transformers-0.4.2.0, transformers-0.4.1.0 (conflict:
pipes => transformers>=0.2.0.0 && <0.4)
rejecting: transformers-0.3.0.0 (conflict: transformers-compat-0.5.1.4:three
=> transformers>=0.2 && <0.3 || >=0.4.1 && <0.6)
rejecting: transformers-0.2.2.1, transformers-0.2.1.0, transformers-0.2.0.0
(conflict: mtl => transformers==0.3.*)
rejecting: transformers-0.1.4.0, transformers-0.1.3.0, transformers-0.1.1.0,
transformers-0.1.0.1, transformers-0.0.1.0, transformers-0.0.0.0,
transformers-0.5.0.2, transformers-0.4.0.0 (conflict: pipes =>
transformers>=0.2.0.0 && <0.4)
rejecting: transformers-0.2.2.0 (conflict: mtl => transformers==0.3.*)
rejecting: transformers-0.1.0.0 (conflict: pipes => transformers>=0.2.0.0 &&
<0.4)
Dependency tree exhaustively searched.