Resolving dependencies...
cabal: Could not resolve dependencies:
next goal: blakesum (user goal)
rejecting: blakesum-0.5 (constraint from user target requires ==0.4)
trying: blakesum-0.4
trying: base-4.9.0.0/installed-4.9... (dependency of blakesum-0.4)
next goal: haskell98 (dependency of blakesum-0.4)
rejecting: haskell98-2.0.0.3, haskell98-2.0.0.2, haskell98-2.0.0.1,
haskell98-2.0.0.0 (conflict: blakesum => haskell98>=1 && <2)
rejecting: haskell98-1.1.0.1, haskell98-1.1.0.0, haskell98-1.0.1.1 (conflict:
base==4.9.0.0/installed-4.9..., haskell98 => base>=3 && <4.6)
rejecting: haskell98-1.0.1.0 (conflict: base==4.9.0.0/installed-4.9...,
haskell98 => base<4.6)
rejecting: haskell98-1.0 (conflict: base==4.9.0.0/installed-4.9..., haskell98
=> base<4.3)
Dependency tree exhaustively searched.