The build is unreachable.

Build log

> /tmp/stackage-build2456$ stack unpack rot13-0.2.0.1@sha256:bd7d540f00b97e2d5106ebe8cf24efab3febb6f0ea5fa73b056ce5839ae18d1d
Unpacked rot13-0.2.0.1 to /tmp/stackage-build2456/rot13-0.2.0.1/
> /tmp/stackage-build2456/rot13-0.2.0.1$ 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/rot13-0.2.0.1$ ./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/rot13-0.2.0.1 --htmldir=/home/circleci/project/builds/nightly/doc/rot13-0.2.0.1 --haddockdir=/home/circleci/project/builds/nightly/doc/rot13-0.2.0.1
Configuring rot13-0.2.0.1...
Warning: Packages using 'cabal-version: >= 1.10' must specify the
'default-language' field for each component (e.g. Haskell98 or Haskell2010).
If a component uses different languages in different modules then list the
other ones in the 'other-languages' field.
> /tmp/stackage-build2456/rot13-0.2.0.1$ ghc -clear-package-db -global-package-db -package-db=/home/circleci/project/builds/nightly/pkgdb Setup
> /tmp/stackage-build2456/rot13-0.2.0.1$ ./Setup build
Preprocessing library for rot13-0.2.0.1..
Building library for rot13-0.2.0.1..
[1 of 1] Compiling Codec.Rot13      ( src/Codec/Rot13.hs, dist/build/Codec/Rot13.o )
> /tmp/stackage-build2456/rot13-0.2.0.1$ ghc -clear-package-db -global-package-db -package-db=/home/circleci/project/builds/nightly/pkgdb Setup
> /tmp/stackage-build2456/rot13-0.2.0.1$ ./Setup copy
Installing library in /home/circleci/project/builds/nightly/lib/x86_64-linux-ghc-8.7.20181117/rot13-0.2.0.1-G1SREXh86lmJEBHgjzNnx8
> /tmp/stackage-build2456/rot13-0.2.0.1$ ghc -clear-package-db -global-package-db -package-db=/home/circleci/project/builds/nightly/pkgdb Setup
> /tmp/stackage-build2456/rot13-0.2.0.1$ ./Setup register
Registering library for rot13-0.2.0.1..