Resolving dependencies...
cabal: Could not resolve dependencies:
next goal: first-class-patterns (user goal)
rejecting: first-class-patterns-0.3.2.3, first-class-patterns-0.3.2.2,
first-class-patterns-0.3.2.1, first-class-patterns-0.3.2,
first-class-patterns-0.3.1 (constraint from user target requires ==0.3.0)
trying: first-class-patterns-0.3.0
trying: base-4.9.0.0/installed-4.9... (dependency of
first-class-patterns-0.3.0)
next goal: transformers (dependency of first-class-patterns-0.3.0)
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,
transformers-0.3.0.0 (conflict: first-class-patterns => transformers>=0.1.0 &&
<0.2.3)
rejecting: transformers-0.2.2.1 (conflict: base==4.9.0.0/installed-4.9...,
transformers => base>=2 && <4.8 || >=1.0 && <2)
rejecting: transformers-0.2.1.0, transformers-0.2.0.0, transformers-0.1.4.0,
transformers-0.1.3.0, transformers-0.1.1.0, transformers-0.1.0.1 (conflict:
base==4.9.0.0/installed-4.9..., transformers => base>=2 && <4.3 || >=1.0 &&
<2)
rejecting: transformers-0.0.1.0, transformers-0.0.0.0, transformers-0.5.0.2,
transformers-0.4.0.0 (conflict: first-class-patterns => transformers>=0.1.0 &&
<0.2.3)
rejecting: transformers-0.2.2.0 (conflict: base==4.9.0.0/installed-4.9...,
transformers => base>=2 && <4.6 || >=1.0 && <2)
rejecting: transformers-0.1.0.0 (conflict: base==4.9.0.0/installed-4.9...,
transformers => base<4.3)
Dependency tree exhaustively searched.