Resolving dependencies...
cabal: Could not resolve dependencies:
next goal: Cabal (user goal)
rejecting: Cabal-1.22.7.0, 1.22.6.0, 1.22.5.0, 1.22.4.0, 1.22.3.0, 1.22.2.0,
1.22.1.1, 1.22.1.0, 1.22.0.0, 1.20.0.4, 1.20.0.3, 1.20.0.2, 1.20.0.1, 1.20.0.0
(global constraint requires ==1.18.1.7)
trying: Cabal-1.18.1.7
trying: base-4.8.1.0/installed-4f7... (dependency of Cabal-1.18.1.7)
trying: aeson-0.10.0.0/installed-9c6... (user goal)
trying: aeson-0.10.0.0/installed-9c6... (user goal)
next goal: eventloop (user goal)
rejecting: eventloop-0.7.0.0/installed-667... (conflict:
aeson==0.10.0.0/installed-9c6..., eventloop =>
aeson==0.8.1.1/installed-3f9...)
rejecting: eventloop-0.7.0.1, 0.7.0.0, 0.6.0.0, 0.5.1.0, 0.5.0.0, 0.4.1.2
(conflict: aeson==0.10.0.0/installed-9c6..., eventloop => aeson>=0.8 && <0.9)
rejecting: eventloop-0.4.1.1, 0.4.1.0, 0.4.0.0, 0.3.0.0, 0.2.1.2, 0.2.1.1
(conflict: base==4.8.1.0/installed-4f7..., eventloop => base>=4.7 && <4.8)
Dependency tree exhaustively searched.

Note: when using a sandbox, all packages are required to have consistent
dependencies. Try reinstalling/unregistering the offending packages or
recreating the sandbox.