Resolving dependencies...
cabal: Could not resolve dependencies:
next goal: btree-concurrent (user goal)
rejecting: btree-concurrent-0.1.5 (constraint from user target requires
==0.1.4)
trying: btree-concurrent-0.1.4
trying: bytestring-0.10.8.1/installed-0.1... (dependency of
btree-concurrent-0.1.4)
next goal: deepseq (dependency of bytestring-0.10.8.1/installed-0.1...)
rejecting: deepseq-1.4.2.0/installed-1.4... (conflict: deepseq =>
array==0.5.1.1/installed-0.5..., btree-concurrent => array==0.4.*)
rejecting: deepseq-1.4.2.0, deepseq-1.4.1.2, deepseq-1.4.1.1, deepseq-1.4.1.0,
deepseq-1.4.0.0, deepseq-1.3.0.2, deepseq-1.3.0.1, deepseq-1.3.0.0,
deepseq-1.2.0.1, deepseq-1.2.0.0, deepseq-1.1.0.2, deepseq-1.1.0.1,
deepseq-1.1.0.0, deepseq-1.0.0.0 (conflict: bytestring =>
deepseq==1.4.2.0/installed-1.4...)
Dependency tree exhaustively searched.