Resolving dependencies...
cabal: Could not resolve dependencies:
next goal: swagger2 (user goal)
rejecting: swagger2-2.1.3, swagger2-2.1.2.1, swagger2-2.1.2, swagger2-2.1.1,
swagger2-2.1, swagger2-2.0.2, swagger2-2.0.1, swagger2-2.0, swagger2-1.2.1,
swagger2-1.2, swagger2-1.1.1, swagger2-1.1, swagger2-1.0, swagger2-0.4.1
(constraint from user target requires ==0.4)
trying: swagger2-0.4
next goal: base (dependency of swagger2-0.4)
rejecting: base-4.9.0.0/installed-4.9... (conflict: swagger2 => base>=4.8 &&
<4.9)
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.