#16220: -Wmissing-signatures should warn when top-level signature is partial -------------------------------------+------------------------------------- Reporter: aspiwack | Owner: (none) Type: feature | Status: new request | Priority: normal | Milestone: Component: Compiler | Version: 8.6.3 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: -------------------------------------+------------------------------------- I'd like GHC to emit a warning for the following definition: {{{#!hs g :: _ g = True }}} But not for that one: {{{#!hs f :: Int f = x where x :: _ x = 1 }}} The context is that I'm using partial signatures to help the type checker give the right type to a binding, with no intention of filling the holes later. (what Richard calls elision [https://github.com/ghc-proposals/ghc- proposals/pull/194 here]) The warning accompanying partial signatures (`-Wpartial-type-signatures`) effectively treats `_`-s in type signatures as holes which are meant to be filled (the type-level equivalent of typed holes). Which is not useful to my usage. I can deactivate `-Wpartial-type-signatures`, however, it seems to me that, in that case, a partial top-level signature is just as bad as a missing top-level signature. So it seems to me that whenever I have `-Wmissing-signatures` enabled I also want to warn for partial top-level signatures. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/16220 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler