The build is unreachable.
Build log
> /tmp/stackage-build2456$ stack unpack flay-0.4@sha256:c5c312f5df6a149eda5e5c8e8ee1ae296ccab8837ea31e2e29eb517b8b0ac426
Unpacked flay-0.4 to /tmp/stackage-build2456/flay-0.4/
> /tmp/stackage-build2456/flay-0.4$ 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/flay-0.4$ ./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/flay-0.4 --htmldir=/home/circleci/project/builds/nightly/doc/flay-0.4 --haddockdir=/home/circleci/project/builds/nightly/doc/flay-0.4
Configuring flay-0.4...
> /tmp/stackage-build2456/flay-0.4$ ghc -clear-package-db -global-package-db -package-db=/home/circleci/project/builds/nightly/pkgdb Setup
> /tmp/stackage-build2456/flay-0.4$ ./Setup build
Preprocessing library for flay-0.4..
Building library for flay-0.4..
[1 of 1] Compiling Flay ( src/Flay.hs, dist/build/Flay.o )
> /tmp/stackage-build2456/flay-0.4$ ghc -clear-package-db -global-package-db -package-db=/home/circleci/project/builds/nightly/pkgdb Setup
> /tmp/stackage-build2456/flay-0.4$ ./Setup copy
Installing library in /home/circleci/project/builds/nightly/lib/x86_64-linux-ghc-8.7.20181117/flay-0.4-AxqQHtbHnSZAEK0C0htqBz
> /tmp/stackage-build2456/flay-0.4$ ghc -clear-package-db -global-package-db -package-db=/home/circleci/project/builds/nightly/pkgdb Setup
> /tmp/stackage-build2456/flay-0.4$ ./Setup register
Registering library for flay-0.4..