Undocumented GHC flags -fbuilding-cabal-package and --package-db

Question

The output of cabal build --verbose mentions flags that are not documented in the man pages. GHC is given a flag -fbuilding-cabal-package . ghc-pkg is given a flag --package-db . My guess is that the latter is a synonym for --package-conf . Am I right? And what is the former?

Answer 1

--package-db is documented in the user guide . It is indeed similar to the old --package-conf flag, see user guide for older ghc .

-fbuilding-cabal-package is indeed undocumented, there is a ticket about that. It is designed to be used by cabal only. It changes few compiler messages to look more clear when building package using cabal.