Resolving dependencies...
cabal: Could not resolve dependencies:
next goal: GPipe (user goal)
rejecting: GPipe-2.1.5, 1.4.1, 2.1.4, 2.1.3, 2.1.2, 2.1.1, 2.1, 2.0.2, 2.0.1,
2.0, 1.4, 1.3.2 (global constraint requires ==1.3.1)
trying: GPipe-1.3.1
trying: base-4.8.1.0/installed-4f7... (dependency of GPipe-1.3.1)
next goal: list-tries (dependency of GPipe-1.3.1)
rejecting: list-tries-0.6.1, 0.6.0, 0.5.2, 0.5.1, 0.5 (conflict: GPipe =>
list-tries>=0.4.1 && <0.5)
rejecting: list-tries-0.4.3 (conflict: base==4.8.1.0/installed-4f7...,
list-tries => base>=3 && <4.7)
rejecting: list-tries-0.4.2 (conflict: base==4.8.1.0/installed-4f7...,
list-tries => base>=3 && <4.6)
rejecting: list-tries-0.4.1 (conflict: base==4.8.1.0/installed-4f7...,
list-tries => base>=3 && <4.4)
rejecting: list-tries-0.4, 0.3, 0.2, 0.1, 0.0 (conflict: GPipe =>
list-tries>=0.4.1 && <0.5)
Dependency tree exhaustively searched.