Warning: The install command is a part of the legacy v1 style of cabal usage.

Please switch to using either the new project style and the new-install
command or the legacy v1-install alias as new-style projects will become the
default in the next version of cabal-install. Please file a bug if you cannot
replicate a working v1- use case with the new-style commands.

For more information, see: https://wiki.haskell.org/Cabal/NewBuild

Resolving dependencies...
cabal: Could not resolve dependencies:
[__0] trying: itanium-abi-0.1.1.0 (user goal)
[__1] trying: unordered-containers-0.2.9.0 (dependency of itanium-abi)
[__2] trying: hashable-1.2.7.0 (dependency of unordered-containers)
[__3] trying: text-1.2.3.1/installed-1.2... (dependency of itanium-abi)
[__4] trying: boomerang-1.4.5.5 (dependency of itanium-abi)
[__5] next goal: template-haskell (dependency of boomerang)
[__5] rejecting: template-haskell-2.14.0.0/installed-2.1... (conflict:
boomerang => template-haskell<2.14)
[__5] rejecting: template-haskell-2.14.0.0, template-haskell-2.13.0.0,
template-haskell-2.12.0.0, template-haskell-2.11.1.0,
template-haskell-2.11.0.0, template-haskell-2.10.0.0,
template-haskell-2.9.0.0, template-haskell-2.8.0.0, template-haskell-2.7.0.0,
template-haskell-2.6.0.0, template-haskell-2.5.0.0, template-haskell-2.4.0.1,
template-haskell-2.4.0.0, template-haskell-2.3.0.1, template-haskell-2.3.0.0,
template-haskell-2.2.0.0 (constraint from non-upgradeable package requires
installed instance)
[__5] fail (backjumping, conflict set: boomerang, template-haskell)
After searching the rest of the dependency tree exhaustively, these were the
goals I've had most trouble fulfilling: template-haskell, text, pretty,
boomerang, itanium-abi, base, hashable, unordered-containers