Resolving dependencies...
cabal: Could not resolve dependencies:
next goal: ghc-core (user goal)
rejecting: ghc-core-0.5.6, ghc-core-0.5.5, ghc-core-0.5.4, ghc-core-0.5.3,
ghc-core-0.5.2, ghc-core-0.5.1, ghc-core-0.5, ghc-core-0.4.3, ghc-core-0.4.2,
ghc-core-0.4.1, ghc-core-0.4 (constraint from user target requires ==0.3.0.1)
trying: ghc-core-0.3.0.1
trying: base-4.9.0.0/installed-4.9... (dependency of ghc-core-0.3.0.1)
next goal: hscolour (dependency of ghc-core-0.3.0.1)
rejecting: hscolour-1.24.1, hscolour-1.24, hscolour-1.23, hscolour-1.22,
hscolour-1.21, hscolour-1.20.3, hscolour-1.20.2, hscolour-1.20.1,
hscolour-1.20, hscolour-1.19, hscolour-1.18, hscolour-1.17, hscolour-1.16,
hscolour-1.15, hscolour-1.14, hscolour-1.13, hscolour-1.12, hscolour-1.11,
hscolour-1.10.1, hscolour-1.10 (conflict: ghc-core => hscolour==1.9)
rejecting: hscolour-1.9 (conflict: base==4.9.0.0/installed-4.9..., hscolour =>
base<4.4)
rejecting: hscolour-1.6 (conflict: ghc-core => hscolour==1.9)
Dependency tree exhaustively searched.