#12845: -XPartialTypeSignatures results in unbound variables -------------------------------------+------------------------------------- Reporter: crockeea | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: GHC rejects | Unknown/Multiple valid program | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by RyanGlScott): If I'm reading this right, this appears to work in GHC HEAD: {{{ $ /opt/ghc/head/bin/ghci Bug.hs GHCi, version 8.1.20161010: http://www.haskell.org/ghc/ :? for help Loaded GHCi configuration from /home/ryanglscott/.ghci [1 of 1] Compiling Main ( Bug.hs, interpreted ) Bug.hs:16:70: warning: [-Wpartial-type-signatures] • Found type wildcard ‘_’ standing for ‘() :: Constraint’ • In the type signature: broken :: forall r r' rngs. ('(r, r') ~ Head rngs, Bar r r' ~ True, _) => Foo r -> Proxy rngs -> () Ok, modules loaded: Main. }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12845#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler