Package: src:ghc Version: 8.8.1+dfsg1+is+8.6.5+dfsg1-2 Something like this seems to be needed because the install target does not ensure that directories are created before files that are installed into them:
diff -Nru ghc-8.8.1+dfsg1+is+8.6.5+dfsg1/debian/rules ghc-8.8.1+dfsg1+is+8.6.5+dfsg1/debian/rules --- ghc-8.8.1+dfsg1+is+8.6.5+dfsg1/debian/rules 2019-09-21 12:06:31.000000000 +0200 +++ ghc-8.8.1+dfsg1+is+8.6.5+dfsg1/debian/rules 2019-11-10 19:03:00.000000000 +0100 @@ -174,7 +174,7 @@ PROF_FILE = \( -name "*.p_*" -o -name "lib*_p.a" \) override_dh_auto_install: - dh_auto_install + dh_auto_install --no-parallel # Delete all the library LICENSE files rm -f debian/tmp/usr/share/doc/ghc-doc/html/libraries/*/LICENSE I saw a build failure due to a missing debian/tmp/usr/bin directory when symlinking haddock, and after the change above, it was gone.