Resolving dependencies...
cabal: Could not resolve dependencies:
next goal: helm (user goal)
rejecting: helm-1.0.0 (constraint from user target requires ==0.7.1)
trying: helm-0.7.1
trying: base-4.9.0.0/installed-4.9... (dependency of helm-0.7.1)
trying: transformers-0.5.2.0/installed-0.5... (dependency of helm-0.7.1)
next goal: mtl (dependency of helm-0.7.1)
rejecting: mtl-2.2.1, mtl-2.2.0.1, mtl-2.2 (conflict: helm => mtl>=2.1 &&
<2.2)
rejecting: mtl-2.1.3.1, mtl-2.1.2 (conflict:
transformers==0.5.2.0/installed-0.5..., mtl => transformers==0.3.*)
rejecting: mtl-2.1.1, mtl-2.1 (conflict: base==4.9.0.0/installed-4.9..., mtl
=> base<4.6)
rejecting: mtl-2.0.1.1, mtl-2.0.1.0, mtl-2.0.0.0, mtl-1.1.1.1, mtl-1.1.1.0,
mtl-1.1.0.2, mtl-1.1.0.1, mtl-1.1.0.0, mtl-1.0 (conflict: helm => mtl>=2.1 &&
<2.2)
Dependency tree exhaustively searched.