Resolving dependencies...
cabal: Could not resolve dependencies:
next goal: btree-concurrent (user goal)
rejecting: btree-concurrent-0.1.5 (global constraint requires ==0.1.4)
trying: btree-concurrent-0.1.4
trying: bytestring-0.10.6.0/installed-236... (dependency of
btree-concurrent-0.1.4)
next goal: deepseq (dependency of bytestring-0.10.6.0/installed-236...)
rejecting: deepseq-1.4.1.1/installed-8fb... (conflict: deepseq =>
array==0.5.1.0/installed-d42..., btree-concurrent => array==0.4.*)
rejecting: deepseq-1.4.1.2, 1.4.1.1, 1.4.1.0, 1.4.0.0, 1.3.0.2, 1.3.0.1,
1.3.0.0, 1.2.0.1, 1.2.0.0, 1.1.0.2, 1.1.0.1, 1.1.0.0, 1.0.0.0 (conflict:
bytestring => deepseq==1.4.1.1/installed-8fb...)
Dependency tree exhaustively searched.