Resolving dependencies...
cabal: Could not resolve dependencies:
next goal: ghc-core (user goal)
rejecting: ghc-core-0.5.6, 0.5.5, 0.5.4, 0.5.3, 0.5.2, 0.5.1, 0.5, 0.4.3,
0.4.2, 0.4.1, 0.4 (global constraint requires ==0.3.0.1)
trying: ghc-core-0.3.0.1
trying: base-4.7.0.1/installed-e4b... (dependency of ghc-core-0.3.0.1)
next goal: hscolour (dependency of ghc-core-0.3.0.1)
rejecting: hscolour-1.23, 1.22, 1.21, 1.20.3, 1.20.2, 1.20.1, 1.20, 1.19,
1.18, 1.17, 1.16, 1.15, 1.14, 1.13, 1.12, 1.11, 1.10.1, 1.10 (conflict:
ghc-core => hscolour==1.9)
rejecting: hscolour-1.9 (conflict: base==4.7.0.1/installed-e4b..., hscolour =>
base<4.4)
rejecting: hscolour-1.6 (conflict: ghc-core => hscolour==1.9)
Dependency tree exhaustively searched.