Resolving dependencies...
cabal: Could not resolve dependencies:
next goal: graphviz (user goal)
rejecting: graphviz-2999.17.0.2, 2999.17.0.1, 2999.17.0.0, 2999.16.0.0,
2999.15.0.1, 2999.15.0.0, 2999.14.1.0, 2999.14.0.0, 2999.13.0.3, 2999.13.0.2,
2999.13.0.1, 2999.13.0.0, 2999.12.0.4, 2999.12.0.3, 2999.12.0.2, 2999.12.0.1,
2999.12.0.0, 2999.11.0.0, 2999.10.0.1 (global constraint requires
==2999.10.0.0)
trying: graphviz-2999.10.0.0
trying: base-4.7.0.1/installed-e4b... (dependency of graphviz-2999.10.0.0)
next goal: polyparse (dependency of graphviz-2999.10.0.0)
rejecting: polyparse-1.11, 1.10, 1.9, 1.8, 1.7, 1.6, 1.5 (conflict: graphviz
=> polyparse==1.4.*)
rejecting: polyparse-1.4.1, 1.4 (conflict: base==4.7.0.1/installed-e4b...,
polyparse => base<4.4)
rejecting: polyparse-1.3, 1.2, 1.1, 1.0 (conflict: graphviz =>
polyparse==1.4.*)
Dependency tree exhaustively searched.