Resolving dependencies...
cabal: Could not resolve dependencies:
next goal: recursion-schemes (user goal)
rejecting: recursion-schemes-4.1.2, 4.1.1, 4.1, 4.0, 3.0.0.2, 3.0.0.1, 3.0,
2.1, 2.0.2, 2.0.1.2, 2.0.1.1, 2.0.1, 2.0 (global constraint requires
==1.8.0.2)
trying: recursion-schemes-1.8.0.2
trying: base-4.8.1.0/installed-4f7... (dependency of
recursion-schemes-1.8.0.2)
next goal: free (dependency of recursion-schemes-1.8.0.2)
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, 2.1.1.1, 2.1.1, 2.1, 2.0.3, 2.0.2,
2.0.1.1, 2.0.1, 2.0 (conflict: recursion-schemes => free>=1.8 && <1.9)
trying: free-1.8.0.4
next goal: semigroups (dependency of free-1.8.0.4)
rejecting: semigroups-0.18.0.1, 0.18, 0.17.0.1, 0.17, 0.16.2.2, 0.16.2.1,
0.16.2, 0.16.1, 0.16.0.1, 0.16, 0.15.4, 0.15.3, 0.15.2, 0.15.1, 0.15, 0.14,
0.13.0.1, 0.13, 0.12.2, 0.12.1, 0.12.0.1, 0.12, 0.11, 0.10, 0.9.2, 0.9.1, 0.9,
0.8.5, 0.8.4.1, 0.8.4, 0.8.3.2, 0.8.3.1, 0.8.3, 0.8.2, 0.8.0.1, 0.8, 0.7.1.2,
0.7.1.1, 0.7.1, 0.7.0 (conflict: free => semigroups>=0.6 && <0.7)
rejecting: semigroups-0.6.1, 0.6 (conflict: base==4.8.1.0/installed-4f7...,
semigroups => base>=4 && <4.5)
rejecting: semigroups-0.5.0.2, 0.5.0.1, 0.5.0, 0.4.0, 0.3.4.2, 0.3.4.1, 0.3.4,
0.3.3, 0.3.2, 0.3.1, 0.3.0, 0.2.0, 0.1.0 (conflict: free => semigroups>=0.6 &&
<0.7)
Dependency tree exhaustively searched.