Resolving dependencies...
cabal: Could not resolve dependencies:
next goal: gl (user goal)
rejecting: gl-0.7.8.1, gl-0.7.8, gl-0.7.7, gl-0.7.6, gl-0.7.5, gl-0.7.4,
gl-0.7.3, gl-0.7.2.4, gl-0.7.2.3, gl-0.7.2.2, gl-0.7.2, gl-0.7.1, gl-0.7,
gl-0.6.3, gl-0.6.2, gl-0.6.1, gl-0.6, gl-0.5, gl-0.4, gl-0.3, gl-0.2, gl-0.1
(constraint from user target requires ==0.7.2.1)
trying: gl-0.7.2.1
next goal: base (dependency of gl-0.7.2.1)
rejecting: base-4.9.0.0/installed-4.9... (conflict: gl => base<0)
rejecting: base-4.9.0.0, base-4.8.2.0, base-4.8.1.0, base-4.8.0.0,
base-4.7.0.2, base-4.7.0.1, base-4.7.0.0, base-4.6.0.1, base-4.6.0.0,
base-4.5.1.0, base-4.5.0.0, base-4.4.1.0, base-4.4.0.0, base-4.3.1.0,
base-4.3.0.0, base-4.2.0.2, base-4.2.0.1, base-4.2.0.0, base-4.1.0.0,
base-4.0.0.0, base-3.0.3.2, base-3.0.3.1 (constraint from non-upgradeable
package requires installed instance)
Dependency tree exhaustively searched.