Resolving dependencies...
cabal: Could not resolve dependencies:
next goal: reactivity (user goal)
rejecting: reactivity-0.3.2.4, reactivity-0.3.2.3, reactivity-0.3.2.1,
reactivity-0.3.2.0, reactivity-0.3.1.0, reactivity-0.3.0.0 (constraint from
user target requires ==0.2.3.0)
trying: reactivity-0.2.3.0
next goal: Displayable (dependency of reactivity-0.2.3.0)
Dependency tree exhaustively searched.