sandbox.out

# cabal v1-sandbox init
Writing a default package environment file to <ROOT>/sandbox.dist/cabal.sandbox.config
Creating a new sandbox at <ROOT>/sandbox.dist/sandbox
# cabal v1-sandbox add-source
# cabal v1-install
Resolving dependencies...
In order, the following would be installed:
Cabal-2.0.0.0 (new version)