Resolving dependencies...
cabal: Could not resolve dependencies:
next goal: ForSyDe (user goal)
rejecting: ForSyDe-3.1.1 (constraint from user target requires ==3.1)
trying: ForSyDe-3.1
trying: base-4.9.0.0/installed-4.9... (dependency of ForSyDe-3.1)
next goal: packedstring (dependency of ForSyDe-3.1)
rejecting: packedstring-0.1.0.1 (conflict: base==4.9.0.0/installed-4.9...,
packedstring => base<4.4)
rejecting: packedstring-0.1.0.0 (conflict: base==4.9.0.0/installed-4.9...,
packedstring => base<4.3)
Dependency tree exhaustively searched.