Resolving dependencies...
cabal: Could not resolve dependencies:
[__0] trying: ihaskell-hvega-0.3.2.0 (user goal)
[__1] trying: ihaskell-0.10.1.2 (dependency of ihaskell-hvega)
[__2] trying: shelly-1.9.0 (dependency of ihaskell)
[__3] trying: async-2.2.2 (dependency of shelly)
[__4] trying: ipython-kernel-0.10.2.1 (dependency of ihaskell)
[__5] next goal: zeromq4-haskell (dependency of ipython-kernel)
[__5] rejecting: zeromq4-haskell-0.8.0, 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 (conflict: pkg-config package libzmq(==4.0 || >4.0) &&
<5.0, not found in the pkg-config database)
[__5] rejecting: zeromq4-haskell-0.6.3 (conflict: async==2.2.2,
zeromq4-haskell => async==2.0.*)
[__5] skipping: 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, zeromq4-haskell-0.2,
zeromq4-haskell-0.1 (has the same characteristics that caused the previous
version to fail: excludes 'async' version 2.2.2)
[__5] fail (backjumping, conflict set: async, ipython-kernel, zeromq4-haskell)
After searching the rest of the dependency tree exhaustively, these were the
goals I've had most trouble fulfilling: async, zeromq4-haskell, ihaskell,
shelly, ipython-kernel, base, ihaskell-hvega
Try running with --minimize-conflict-set to improve the error message.