Resolving dependencies...
cabal: Could not resolve dependencies:
[__0] next goal: hakyll (user goal)
[__0] rejecting: hakyll-4.13.4.1, hakyll-4.13.4.0, hakyll-4.13.3.0,
hakyll-4.13.2.0 (constraint from user target requires ==4.13.1.0)
[__0] trying: hakyll-4.13.1.0
[__1] trying: hakyll:+usepandoc
[__2] next goal: pandoc (dependency of hakyll +usepandoc)
[__2] rejecting: pandoc-2.11.0.4, pandoc-2.11.0.2, pandoc-2.11.0.1,
pandoc-2.11, pandoc-2.10.1, pandoc-2.10 (conflict: hakyll +usepandoc =>
pandoc>=2.0.5 && <2.10)
[__2] trying: pandoc-2.9.2.1
[__3] next goal: haddock-library (dependency of pandoc)
[__3] rejecting: haddock-library-1.9.0 (conflict: pandoc =>
haddock-library>=1.8 && <1.9)
[__3] trying: haddock-library-1.8.0
[__4] next goal: base (dependency of hakyll)
[__4] rejecting: base-4.14.1.0/installed-4.14.1.0 (conflict: haddock-library
=> base>=4.7 && <4.14)
[__4] skipping: base-4.14.0.0 (has the same characteristics that caused the
previous version to fail: excluded by constraint '>=4.7 && <4.14' from
'haddock-library')
[__4] rejecting: base-4.13.0.0, base-4.12.0.0, base-4.11.1.0, base-4.11.0.0,
base-4.10.1.0, base-4.10.0.0, base-4.9.1.0, base-4.9.0.0, base-4.8.2.0,
base-4.8.1.0, base-4.8.0.0, base-4.7.0.2, base-4.7.0.1, base-4.7.0.0,
base-4.6.0.1, base-4.6.0.0, base-4.5.1.0, base-4.5.0.0, base-4.4.1.0,
base-4.4.0.0, base-4.3.1.0, base-4.3.0.0, base-4.2.0.2, base-4.2.0.1,
base-4.2.0.0, base-4.1.0.0, base-4.0.0.0, base-3.0.3.2, base-3.0.3.1
(constraint from non-upgradeable package requires installed instance)
[__4] fail (backjumping, conflict set: base, haddock-library, hakyll)
After searching the rest of the dependency tree exhaustively, these were the
goals I've had most trouble fulfilling: hakyll, pandoc, base, haddock-library,
hakyll:usepandoc
Try running with --minimize-conflict-set to improve the error message.