Resolving dependencies...
Error: cabal: Could not resolve dependencies:
[__0] trying: hMPC-0.1.0.0 (user goal)
[__1] trying: vector-0.13.1.0 (dependency of hMPC)
[__2] trying: primitive-0.9.0.0 (dependency of vector)
[__3] trying: transformers-0.6.1.0/installed-0.6.1.0 (dependency of primitive)
[__4] next goal: mtl (dependency of hMPC)
[__4] rejecting: mtl-2.3.1/installed-2.3.1 (conflict: hMPC => mtl>=2.2.2 &&
<2.3)
[__4] skipping: mtl-2.3.1 (has the same characteristics that caused the
previous version to fail: excluded by constraint '>=2.2.2 && <2.3' from
'hMPC')
[__4] rejecting: mtl-2.2.2 (conflict: transformers==0.6.1.0/installed-0.6.1.0,
mtl => transformers>=0.4 && <0.6)
[__4] skipping: mtl-2.2.1, mtl-2.2.0.1, mtl-2.2, mtl-2.1.3.1, mtl-2.1.2,
mtl-2.1.1, mtl-2.0.1.1, mtl-2.0.1.0, mtl-2.0.0.0 (has the same characteristics
that caused the previous version to fail: excludes 'transformers' version
0.6.1.0)
[__4] rejecting: mtl-1.1.1.1 (conflict: hMPC => mtl>=2.2.2 && <2.3)
[__4] skipping: mtl-1.1.1.0, mtl-1.1.0.2, mtl-1.1.0.1, mtl-1.1.0.0, mtl-1.0,
mtl-2.3, mtl-2.1 (has the same characteristics that caused the previous
version to fail: excluded by constraint '>=2.2.2 && <2.3' from 'hMPC')
[__4] fail (backjumping, conflict set: hMPC, mtl, transformers)
After searching the rest of the dependency tree exhaustively, these were the
goals I've had most trouble fulfilling: hMPC, lens, base, semigroupoids,
transformers, vector, mtl, primitive
Try running with --minimize-conflict-set to improve the error message.