The build is unreachable.
Build log
> /tmp/stackage-build2456$ stack unpack rainbox-0.20.0.0@sha256:92e08d1d6b2c0a2361e26b38590349e8a57ddfa4aa0484ab3bce5c20b71e5176
Unpacked rainbox-0.20.0.0 to /tmp/stackage-build2456/rainbox-0.20.0.0/
> /tmp/stackage-build2456/rainbox-0.20.0.0$ ghc -clear-package-db -global-package-db -package-db=/home/circleci/project/builds/nightly/pkgdb Setup
[1 of 1] Compiling Main ( Setup.hs, Setup.o )
Linking Setup ...
> /tmp/stackage-build2456/rainbox-0.20.0.0$ ./Setup configure --package-db=clear --package-db=global --package-db=/home/circleci/project/builds/nightly/pkgdb --libdir=/home/circleci/project/builds/nightly/lib --bindir=/home/circleci/project/builds/nightly/bin --datadir=/home/circleci/project/builds/nightly/share --libexecdir=/home/circleci/project/builds/nightly/libexec --sysconfdir=/home/circleci/project/builds/nightly/etc --docdir=/home/circleci/project/builds/nightly/doc/rainbox-0.20.0.0 --htmldir=/home/circleci/project/builds/nightly/doc/rainbox-0.20.0.0 --haddockdir=/home/circleci/project/builds/nightly/doc/rainbox-0.20.0.0
Configuring rainbox-0.20.0.0...
> /tmp/stackage-build2456/rainbox-0.20.0.0$ ghc -clear-package-db -global-package-db -package-db=/home/circleci/project/builds/nightly/pkgdb Setup
> /tmp/stackage-build2456/rainbox-0.20.0.0$ ./Setup build
Preprocessing library for rainbox-0.20.0.0..
Building library for rainbox-0.20.0.0..
[1 of 4] Compiling Paths_rainbox ( dist/build/autogen/Paths_rainbox.hs, dist/build/Paths_rainbox.o )
[2 of 4] Compiling Rainbox.Core ( lib/Rainbox/Core.hs, dist/build/Rainbox/Core.o )
[3 of 4] Compiling Rainbox ( lib/Rainbox.hs, dist/build/Rainbox.o )
[4 of 4] Compiling Rainbox.Tutorial ( lib/Rainbox/Tutorial.hs, dist/build/Rainbox/Tutorial.o )
> /tmp/stackage-build2456/rainbox-0.20.0.0$ ghc -clear-package-db -global-package-db -package-db=/home/circleci/project/builds/nightly/pkgdb Setup
> /tmp/stackage-build2456/rainbox-0.20.0.0$ ./Setup copy
Installing library in /home/circleci/project/builds/nightly/lib/x86_64-linux-ghc-8.7.20181116/rainbox-0.20.0.0-1VYurLd8PfT2MnwWosw0iP
> /tmp/stackage-build2456/rainbox-0.20.0.0$ ghc -clear-package-db -global-package-db -package-db=/home/circleci/project/builds/nightly/pkgdb Setup
> /tmp/stackage-build2456/rainbox-0.20.0.0$ ./Setup register
Registering library for rainbox-0.20.0.0..