Resolving dependencies... cabal: Could not resolve dependencies: next goal: yesod-auth-kerberos (user goal) rejecting: yesod-auth-kerberos-1.4.3, 1.4.2 (global constraint requires ==1.4.1) trying: yesod-auth-kerberos-1.4.1 next goal: transformers (dependency of yesod-auth-kerberos-1.4.1) rejecting: transformers-0.4.2.0/installed-21d..., 0.4.3.0, 0.4.2.0, 0.4.1.0 (conflict: yesod-auth-kerberos => transformers>=0.2.2 && <0.4) trying: transformers-0.3.0.0 trying: shakespeare-2.0.7 (dependency of yesod-auth-kerberos-1.4.1) trying: exceptions-0.8.0.2 (dependency of shakespeare-2.0.7) trying: transformers-compat-0.4.0.4 (dependency of exceptions-0.8.0.2) trying: transformers-compat-0.4.0.4:-two rejecting: transformers-compat-0.4.0.4:-three (conflict: transformers==0.3.0.0, transformers-compat-0.4.0.4:three => transformers>=0.4.1 && <0.5) rejecting: transformers-compat-0.4.0.4:+three (manual flag can only be changed explicitly) Dependency tree exhaustively searched.