The build is unreachable.

Build log

> /tmp/stackage-build2451$ stack unpack monad-loops-0.4.3@sha256:ada4f1295ece07f9a7398bc5b40c4532f95a733a8604d2a2f57f05f878766df2
Unpacked monad-loops-0.4.3 to /tmp/stackage-build2451/monad-loops-0.4.3/
> /tmp/stackage-build2451/monad-loops-0.4.3$ 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-build2451/monad-loops-0.4.3$ ./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/monad-loops-0.4.3 --htmldir=/home/circleci/project/builds/nightly/doc/monad-loops-0.4.3 --haddockdir=/home/circleci/project/builds/nightly/doc/monad-loops-0.4.3
Configuring monad-loops-0.4.3...
> /tmp/stackage-build2451/monad-loops-0.4.3$ ghc -clear-package-db -global-package-db -package-db=/home/circleci/project/builds/nightly/pkgdb Setup
> /tmp/stackage-build2451/monad-loops-0.4.3$ ./Setup build
Preprocessing library for monad-loops-0.4.3..
Building library for monad-loops-0.4.3..
[1 of 1] Compiling Control.Monad.Loops ( src/Control/Monad/Loops.hs, dist/build/Control/Monad/Loops.o )
> /tmp/stackage-build2451/monad-loops-0.4.3$ ghc -clear-package-db -global-package-db -package-db=/home/circleci/project/builds/nightly/pkgdb Setup
> /tmp/stackage-build2451/monad-loops-0.4.3$ ./Setup copy
Installing library in /home/circleci/project/builds/nightly/lib/x86_64-linux-ghc-8.7.20181119/monad-loops-0.4.3-1JmYXd2DuhL32x6L8Quh7l
> /tmp/stackage-build2451/monad-loops-0.4.3$ ghc -clear-package-db -global-package-db -package-db=/home/circleci/project/builds/nightly/pkgdb Setup
> /tmp/stackage-build2451/monad-loops-0.4.3$ ./Setup register
Registering library for monad-loops-0.4.3..