Resolving dependencies...
cabal: Could not resolve dependencies:
[__0] trying: zre-0.1.1.0 (user goal)
[__1] next goal: zeromq4-haskell (dependency of zre)
[__1] 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, 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 || >4.0) && <5.0, not found in the pkg-config
database)
[__1] trying: zeromq4-haskell-0.2
[__2] trying: transformers-0.5.5.0/installed-0.5.5.0 (dependency of
zeromq4-haskell)
[__3] next goal: MonadCatchIO-transformers (dependency of zeromq4-haskell)
[__3] rejecting: MonadCatchIO-transformers-0.3.1.3 (conflict: transformers =>
base==4.12.0.0/installed-4.12.0.0, MonadCatchIO-transformers => base<4.9)
[__3] rejecting: MonadCatchIO-transformers-0.3.1.2,
MonadCatchIO-transformers-0.3.1.1, MonadCatchIO-transformers-0.3.1.0
(conflict: transformers => base==4.12.0.0/installed-4.12.0.0,
MonadCatchIO-transformers => base<4.8)
[__3] rejecting: MonadCatchIO-transformers-0.3.0.0,
MonadCatchIO-transformers-0.2.2.3, MonadCatchIO-transformers-0.2.2.2,
MonadCatchIO-transformers-0.2.2.1, MonadCatchIO-transformers-0.2.2.0,
MonadCatchIO-transformers-0.2.1.0, MonadCatchIO-transformers-0.2.0.0
(conflict: transformers => base==4.12.0.0/installed-4.12.0.0,
MonadCatchIO-transformers => base<4.7)
[__3] rejecting: MonadCatchIO-transformers-0.1.0.1 (conflict:
transformers==0.5.5.0/installed-0.5.5.0, MonadCatchIO-transformers =>
transformers==0.1.*)
[__3] skipping: MonadCatchIO-transformers-0.1.0.0,
MonadCatchIO-transformers-0.0.2.0, MonadCatchIO-transformers-0.0.1.0 (has the
same characteristics that caused the previous version to fail: excludes
'transformers' version 0.5.5.0)
[__3] fail (backjumping, conflict set: MonadCatchIO-transformers,
transformers, zeromq4-haskell)
After searching the rest of the dependency tree exhaustively, these were the
goals I've had most trouble fulfilling: MonadCatchIO-transformers,
transformers, zeromq4-haskell, base, zre
Try running with --minimize-conflict-set to improve the error message.