The build is unreachable.

Build log

> /tmp/stackage-build2452$ stack unpack doctest-0.16.0.1@sha256:0c8d44a0a781a6c277260788d9c1929f853cf2cb7d2ca36691222d01ddac1934
Unpacked doctest-0.16.0.1 to /tmp/stackage-build2452/doctest-0.16.0.1/
> /tmp/stackage-build2452/doctest-0.16.0.1$ 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-build2452/doctest-0.16.0.1$ ./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/doctest-0.16.0.1 --htmldir=/home/circleci/project/builds/nightly/doc/doctest-0.16.0.1 --haddockdir=/home/circleci/project/builds/nightly/doc/doctest-0.16.0.1
Configuring doctest-0.16.0.1...
> /tmp/stackage-build2452/doctest-0.16.0.1$ ghc -clear-package-db -global-package-db -package-db=/home/circleci/project/builds/nightly/pkgdb Setup
> /tmp/stackage-build2452/doctest-0.16.0.1$ ./Setup build
Preprocessing library for doctest-0.16.0.1..
Building library for doctest-0.16.0.1..
[ 1 of 16] Compiling GhcUtil          ( src/GhcUtil.hs, dist/build/GhcUtil.o )
[ 2 of 16] Compiling Language.Haskell.GhciWrapper ( ghci-wrapper/src/Language/Haskell/GhciWrapper.hs, dist/build/Language/Haskell/GhciWrapper.o )
[ 3 of 16] Compiling Interpreter      ( src/Interpreter.hs, dist/build/Interpreter.o )
[ 4 of 16] Compiling Location         ( src/Location.hs, dist/build/Location.o )
[ 5 of 16] Compiling Paths_doctest    ( dist/build/autogen/Paths_doctest.hs, dist/build/Paths_doctest.o )
[ 6 of 16] Compiling Options          ( src/Options.hs, dist/build/Options.o )
[ 7 of 16] Compiling Sandbox          ( src/Sandbox.hs, dist/build/Sandbox.o )
[ 8 of 16] Compiling PackageDBs       ( src/PackageDBs.hs, dist/build/PackageDBs.o )
[ 9 of 16] Compiling Util             ( src/Util.hs, dist/build/Util.o )
[10 of 16] Compiling Extract          ( src/Extract.hs, dist/build/Extract.o )
[11 of 16] Compiling Parse            ( src/Parse.hs, dist/build/Parse.o )
[12 of 16] Compiling Runner.Example   ( src/Runner/Example.hs, dist/build/Runner/Example.o )
[13 of 16] Compiling Property         ( src/Property.hs, dist/build/Property.o )
[14 of 16] Compiling Runner           ( src/Runner.hs, dist/build/Runner.o )
[15 of 16] Compiling Run              ( src/Run.hs, dist/build/Run.o )
[16 of 16] Compiling Test.DocTest     ( src/Test/DocTest.hs, dist/build/Test/DocTest.o )
Preprocessing executable 'doctest' for doctest-0.16.0.1..
Building executable 'doctest' for doctest-0.16.0.1..
[1 of 2] Compiling Main             ( driver/Main.hs, dist/build/doctest/doctest-tmp/Main.o )
[2 of 2] Compiling Paths_doctest    ( dist/build/doctest/autogen/Paths_doctest.hs, dist/build/doctest/doctest-tmp/Paths_doctest.o )
Linking dist/build/doctest/doctest ...
> /tmp/stackage-build2452/doctest-0.16.0.1$ ghc -clear-package-db -global-package-db -package-db=/home/circleci/project/builds/nightly/pkgdb Setup
> /tmp/stackage-build2452/doctest-0.16.0.1$ ./Setup copy
Installing library in /home/circleci/project/builds/nightly/lib/x86_64-linux-ghc-8.7.20181119/doctest-0.16.0.1-EEzlFGmYhRY43Iv9evZ7Q6
Installing executable doctest in /home/circleci/project/builds/nightly/bin
> /tmp/stackage-build2452/doctest-0.16.0.1$ ghc -clear-package-db -global-package-db -package-db=/home/circleci/project/builds/nightly/pkgdb Setup
> /tmp/stackage-build2452/doctest-0.16.0.1$ ./Setup register
Registering library for doctest-0.16.0.1..