Resolving dependencies...
cabal: Could not resolve dependencies:
[__0] trying: yi-frontend-vty-0.18.0 (user goal)
[__1] next goal: yi-language (dependency of yi-frontend-vty)
[__1] rejecting: yi-language-0.17.1, yi-language-0.17.0, yi-language-0.16.0,
yi-language-0.15.0, yi-language-0.14.1, yi-language-0.14.0,
yi-language-0.13.7, yi-language-0.13.6, yi-language-0.13.5,
yi-language-0.13.4, yi-language-0.13.3, yi-language-0.13.2,
yi-language-0.13.1, yi-language-0.13.0.2, yi-language-0.13.0.1,
yi-language-0.13, yi-language-0.2.1, yi-language-0.2.0, yi-language-0.1.1.0,
yi-language-0.1.0.8, yi-language-0.1.0.7, yi-language-0.1.0.6,
yi-language-0.1.0.5, yi-language-0.1.0.4, yi-language-0.1.0.3,
yi-language-0.1.0.2, yi-language-0.1.0.1, yi-language-0.1.0.0 (conflict:
yi-frontend-vty => yi-language>=0.18)
After searching the rest of the dependency tree exhaustively, these were the
goals I've had most trouble fulfilling: yi-frontend-vty, yi-language