#15838: Warn about unused dependencies -------------------------------------+------------------------------------- Reporter: Yuras | Owner: (none) Type: feature | Status: new request | Priority: normal | Milestone: Component: Compiler | Version: 8.6.1 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- GHC loads packages lazily, so at the end of compilation (at least in `--make` mode) it knows all the dependencies, required to compile the code. See `eps_PIT` in `ExternalPackageState`. If we compare this list with the list of packages, passed on command like via `--package-id`, then we'll get a list of unused dependencies. I propose to add a flag `-Wunused-packages`, off by default, which will report the unused packages if any. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15838 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler