Resolving dependencies...
cabal: Could not resolve dependencies:
[__0] trying: zeromq4-clone-pattern-0.1.0.0 (user goal)
[__1] next goal: zeromq4-haskell (dependency of zeromq4-clone-pattern)
[__1] rejecting: zeromq4-haskell-0.7.0, zeromq4-haskell-0.6.7,
zeromq4-haskell-0.6.6, zeromq4-haskell-0.6.5, zeromq4-haskell-0.6.4,
zeromq4-haskell-0.6.3, zeromq4-haskell-0.6.2, zeromq4-haskell-0.6.1,
zeromq4-haskell-0.6, zeromq4-haskell-0.5.1, zeromq4-haskell-0.5,
zeromq4-haskell-0.4.1, zeromq4-haskell-0.4, zeromq4-haskell-0.3.2,
zeromq4-haskell-0.3.1, zeromq4-haskell-0.3 (conflict: pkg-config package
libzmq>=4.0 && <5.0, not found in the pkg-config database)
[__1] trying: zeromq4-haskell-0.2
[__2] trying: MonadCatchIO-transformers-0.3.1.3 (dependency of
zeromq4-haskell)
[__3] next goal: transformers (dependency of zeromq4-clone-pattern)
[__3] rejecting: transformers-0.5.2.0/installed-0.5..., transformers-0.5.5.0,
transformers-0.5.4.0, transformers-0.5.2.0, transformers-0.5.1.0,
transformers-0.5.0.1, transformers-0.5.0.0 (conflict:
MonadCatchIO-transformers => transformers>=0.2 && <0.5)
[__3] trying: transformers-0.4.3.0
[__4] next goal: base (dependency of zeromq4-clone-pattern)
[__4] rejecting: base-4.10.1.0/installed-4.1... (conflict:
MonadCatchIO-transformers => base<4.9)
[__4] rejecting: 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: MonadCatchIO-transformers, base,
zeromq4-clone-pattern)
After searching the rest of the dependency tree exhaustively, these were the
goals I've had most trouble fulfilling: MonadCatchIO-transformers,
transformers, base, zeromq4-haskell, zeromq4-clone-pattern