Resolving dependencies...
cabal: Could not resolve dependencies:
next goal: vacuum-cairo (user goal)
rejecting: vacuum-cairo-0.5, vacuum-cairo-0.4.1, vacuum-cairo-0.4,
vacuum-cairo-0.3.1, vacuum-cairo-0.3 (constraint from user target requires
==0.2)
trying: vacuum-cairo-0.2
trying: base-4.9.0.0/installed-4.9... (dependency of vacuum-cairo-0.2)
next goal: strict-concurrency (dependency of vacuum-cairo-0.2)
rejecting: strict-concurrency-0.2.4.1, strict-concurrency-0.2.4 (conflict:
base==4.9.0.0/installed-4.9..., strict-concurrency => base>=4 && <4.6)
rejecting: strict-concurrency-0.2.3 (conflict: base==4.9.0.0/installed-4.9...,
strict-concurrency => base>=3 && <4.3)
rejecting: strict-concurrency-0.2.2, strict-concurrency-0.2.1 (conflict:
base==4.9.0.0/installed-4.9..., strict-concurrency => base>=3 && <4)
rejecting: strict-concurrency-0.2, strict-concurrency-0.1 (conflict:
base==4.9.0.0/installed-4.9..., strict-concurrency => base<4.3)
Dependency tree exhaustively searched.