Resolving dependencies...
cabal: Could not resolve dependencies:
trying: GLFW-b-1.4.7.3/installed-fef... (user goal)
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-0.7.0.0, 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: GLFW-b => base==4.8.1.0/installed-4f7..., eventloop => base>=4.7 &&
<4.8)
Backjump limit reached (change with --max-backjumps).

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