The build is unreachable.

Build log

> /tmp/stackage-build2455$ stack unpack csp-1.4.0@sha256:051beb4864f737ea42377918e0c13a7aef4ee5c6f4f39993cc224f6f5bbf470d
Unpacked csp-1.4.0 to /tmp/stackage-build2455/csp-1.4.0/
> /tmp/stackage-build2455/csp-1.4.0$ 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-build2455/csp-1.4.0$ ./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/csp-1.4.0 --htmldir=/home/circleci/project/builds/nightly/doc/csp-1.4.0 --haddockdir=/home/circleci/project/builds/nightly/doc/csp-1.4.0
Configuring csp-1.4.0...
> /tmp/stackage-build2455/csp-1.4.0$ ghc -clear-package-db -global-package-db -package-db=/home/circleci/project/builds/nightly/pkgdb Setup
> /tmp/stackage-build2455/csp-1.4.0$ ./Setup build
Preprocessing library for csp-1.4.0..
Building library for csp-1.4.0..
[1 of 1] Compiling Control.Monad.CSP ( src/Control/Monad/CSP.hs, dist/build/Control/Monad/CSP.o )
> /tmp/stackage-build2455/csp-1.4.0$ ghc -clear-package-db -global-package-db -package-db=/home/circleci/project/builds/nightly/pkgdb Setup
> /tmp/stackage-build2455/csp-1.4.0$ ./Setup copy
Installing library in /home/circleci/project/builds/nightly/lib/x86_64-linux-ghc-8.7.20181122/csp-1.4.0-HivsAr4rP4vHWzlvTG0fld
> /tmp/stackage-build2455/csp-1.4.0$ ghc -clear-package-db -global-package-db -package-db=/home/circleci/project/builds/nightly/pkgdb Setup
> /tmp/stackage-build2455/csp-1.4.0$ ./Setup register
Registering library for csp-1.4.0..