Resolving dependencies...
cabal: Could not resolve dependencies:
next goal: kevin (user goal)
rejecting: kevin-0.11.0, 0.10.0, 0.9.0, 0.8.2, 0.8.1, 0.8, 0.7.2, 0.7.1, 0.7,
0.6.1, 0.6, 0.5, 0.4, 0.2, 0.1.6, 0.1.5.4, 0.1.5.3, 0.1.5.2 (global constraint
requires ==0.1.5.1)
trying: kevin-0.1.5.1
next goal: tls-extra (dependency of kevin-0.1.5.1)
rejecting: tls-extra-0.6.6, 0.6.5, 0.6.4, 0.6.3, 0.6.1, 0.6.0, 0.5.1, 0.5.0
(conflict: kevin => tls-extra==0.4.*)
trying: tls-extra-0.4.7.1
next goal: certificate (dependency of tls-extra-0.4.7.1)
rejecting: certificate-1.3.9, 1.3.8, 1.3.7, 1.3.6, 1.3.5, 1.3.3, 1.3.2, 1.3.1,
1.3.0 (conflict: tls-extra => certificate>=1.2.0 && <1.3.0)
trying: certificate-1.2.9
trying: process-1.2.0.0/installed-163... (dependency of certificate-1.2.9)
next goal: unix (dependency of process-1.2.0.0/installed-163...)
rejecting: unix-2.7.0.1/installed-0d8... (conflict: unix =>
bytestring==0.10.4.0/installed-9f4..., kevin => bytestring==0.9.*)
rejecting: unix-2.7.1.0, 2.7.0.1, 2.7.0.0, 2.6.0.1, 2.6.0.0, 2.5.1.1, 2.5.1.0,
2.5.0.0, 2.4.2.0, 2.4.1.0, 2.4.0.2, 2.4.0.1, 2.4.0.0, 2.3.2.0, 2.3.1.0,
2.3.0.0, 2.2.0.0, 2.0 (conflict: process => unix==2.7.0.1/installed-0d8...)
Dependency tree exhaustively searched.