Warning: The install command is a part of the legacy v1 style of cabal usage.

Please switch to using either the new project style and the new-install
command or the legacy v1-install alias as new-style projects will become the
default in the next version of cabal-install. Please file a bug if you cannot
replicate a working v1- use case with the new-style commands.

For more information, see: https://wiki.haskell.org/Cabal/NewBuild

Resolving dependencies...
Starting     dec-0.0.3
Building     dec-0.0.3
Completed    dec-0.0.3
Downloading  singleton-bool-0.1.5
Downloaded   singleton-bool-0.1.5
Starting     singleton-bool-0.1.5
Building     singleton-bool-0.1.5
Completed    singleton-bool-0.1.5