Resolving dependencies...
cabal: Could not resolve dependencies:
next goal: trifecta (user goal)
rejecting: trifecta-1.5.1.3, 1.5.1.2, 1.5.1.1, 1.5.1, 1.5, 1.4.3, 1.4.2,
1.4.1, 1.4, 1.2.1.1, 1.2.1, 1.2, 1.1, 1.0, 0.53, 0.52, 0.51.0.1, 0.51,
0.50.2.1, 0.50.1, 0.50, 0.49.1 (global constraint requires ==0.49)
trying: trifecta-0.49
trying: base-4.7.0.1/installed-e4b... (dependency of trifecta-0.49)
next goal: keys (dependency of trifecta-0.49)
rejecting: keys-3.10.2, 3.10.1, 3.10, 3.0.4, 3.0.3, 3.0.2, 3.0.1.1, 3.0.1,
3.0, 2.2 (conflict: trifecta => keys>=2.1.1.1 && <2.2)
trying: keys-2.1.3.2
next goal: free (dependency of keys-2.1.3.2)
rejecting: free-4.12.1, 4.12, 4.11, 4.10.0.1, 4.9, 4.8.0.1, 4.8, 4.7.1, 4.7,
4.6.1, 4.6, 4.5, 4.4, 4.2, 4.1, 4.0, 3.4.2, 3.4.1, 3.4, 3.3.1, 3.3.0.2,
3.3.0.1, 3.3, 3.2, 3.1.1, 3.1, 3.0, 2.2 (conflict: keys => free>=2.1.1 &&
<2.2)
trying: free-2.1.1.1
next goal: comonad (dependency of trifecta-0.49)
rejecting: comonad-4.2.7, 4.2.6, 4.2.5, 4.2.4, 4.2.3, 4.2.2, 4.2.1, 4.2,
4.0.1, 4.0, 3.1, 3.0.3, 3.0.2, 3.0.1.1, 3.0.0.2, 3.0.0.1, 3.0 (conflict:
trifecta => comonad>=1.1.1.1 && <1.2)
rejecting: comonad-1.1.1.6, 1.1.1.5 (conflict: base==4.7.0.1/installed-e4b...,
comonad => base>=4 && <4.7)
rejecting: comonad-1.1.1.4, 1.1.1.3, 1.1.1.2, 1.1.1.1 (conflict: free =>
comonad>=1.1.1.5 && <1.2)
rejecting: comonad-1.1.1, 1.1.0.2, 1.1.0.1, 1.1.0, 1.0.3, 1.0.2, 1.0.1, 1.0,
0.9.0.1, 0.9.0, 0.7.0, 0.6.2.1, 0.6.2, 0.6.1.2, 0.6.1.1, 0.6.1, 0.6.0, 0.5.0,
0.4.0, 0.3.0, 0.1.1, 0.1.0 (conflict: trifecta => comonad>=1.1.1.1 && <1.2)
Dependency tree exhaustively searched.