The build is unreachable.

Build log

> /tmp/stackage-build2453$ stack unpack half-0.3@sha256:48cc70e3cd42ccd13039b8d5865ca3aeffe526572aff7e2baf9cf9c28bc31eeb
Unpacked half-0.3 to /tmp/stackage-build2453/half-0.3/
> /tmp/stackage-build2453/half-0.3$ 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-build2453/half-0.3$ ./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/half-0.3 --htmldir=/home/circleci/project/builds/nightly/doc/half-0.3 --haddockdir=/home/circleci/project/builds/nightly/doc/half-0.3
Configuring half-0.3...
> /tmp/stackage-build2453/half-0.3$ ghc -clear-package-db -global-package-db -package-db=/home/circleci/project/builds/nightly/pkgdb Setup
> /tmp/stackage-build2453/half-0.3$ ./Setup build
Preprocessing library for half-0.3..
Building library for half-0.3..
[1 of 1] Compiling Numeric.Half     ( src/Numeric/Half.hs, dist/build/Numeric/Half.o )
> /tmp/stackage-build2453/half-0.3$ ghc -clear-package-db -global-package-db -package-db=/home/circleci/project/builds/nightly/pkgdb Setup
> /tmp/stackage-build2453/half-0.3$ ./Setup copy
Installing library in /home/circleci/project/builds/nightly/lib/x86_64-linux-ghc-8.7.20181115/half-0.3-KRMSyzUdV8g8FBP2q6oD8T
> /tmp/stackage-build2453/half-0.3$ ghc -clear-package-db -global-package-db -package-db=/home/circleci/project/builds/nightly/pkgdb Setup
> /tmp/stackage-build2453/half-0.3$ ./Setup register
Registering library for half-0.3..