The build is unreachable.

Build log

> /tmp/stackage-build2454$ stack unpack scrypt-0.5.0@sha256:d01de43bb28cc449c085932201be5d5e9f141761a424600594f00cfce7f53edb
Unpacked scrypt-0.5.0 to /tmp/stackage-build2454/scrypt-0.5.0/
> /tmp/stackage-build2454/scrypt-0.5.0$ 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-build2454/scrypt-0.5.0$ ./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/scrypt-0.5.0 --htmldir=/home/circleci/project/builds/nightly/doc/scrypt-0.5.0 --haddockdir=/home/circleci/project/builds/nightly/doc/scrypt-0.5.0
Configuring scrypt-0.5.0...
> /tmp/stackage-build2454/scrypt-0.5.0$ ghc -clear-package-db -global-package-db -package-db=/home/circleci/project/builds/nightly/pkgdb Setup
> /tmp/stackage-build2454/scrypt-0.5.0$ ./Setup build
Preprocessing library for scrypt-0.5.0..
Building library for scrypt-0.5.0..
[1 of 1] Compiling Crypto.Scrypt    ( src/Crypto/Scrypt.hs, dist/build/Crypto/Scrypt.o )

src/Crypto/Scrypt.hs:24:1: warning: [-Wunused-imports]
    The import of ‘Control.Applicative’ is redundant
      except perhaps to import instances from ‘Control.Applicative’
    To import instances alone, use: import Control.Applicative()
   |
24 | import Control.Applicative
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^
> /tmp/stackage-build2454/scrypt-0.5.0$ ghc -clear-package-db -global-package-db -package-db=/home/circleci/project/builds/nightly/pkgdb Setup
> /tmp/stackage-build2454/scrypt-0.5.0$ ./Setup copy
Installing library in /home/circleci/project/builds/nightly/lib/x86_64-linux-ghc-8.7.20181117/scrypt-0.5.0-GV1V8vwImNQDlU4HXmeBjT
> /tmp/stackage-build2454/scrypt-0.5.0$ ghc -clear-package-db -global-package-db -package-db=/home/circleci/project/builds/nightly/pkgdb Setup
> /tmp/stackage-build2454/scrypt-0.5.0$ ./Setup register
Registering library for scrypt-0.5.0..