#11016: PartialTypeSignatures trigger bogus "unbound implicit parameter" error -------------------------------------+------------------------------------- Reporter: gridaphobe | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: GHC rejects | Unknown/Multiple valid program | Test Case: Blocked By: | Blocking: Related Tickets: #10846 | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by gridaphobe): I see that commit 1e041b7 addresses this issue and fixes the 'unbound implicit parameter' error (thanks!!), but ghc still refuses to compile `f2`. {{{ % ./inplace/bin/ghc-stage2 Bad.hs [1 of 1] Compiling Bad ( Bad.hs, Bad.o ) Bad.hs:9:1: error: • Could not deduce: ?loc::t from the context: ?loc::Int bound by the inferred type for ‘f2’: (?loc::Int) => t at Bad.hs:9:1-9 • When checking that the inferred type f2 :: forall t. (?loc::t) => t is as general as its (partial) signature f2 :: forall t. (?loc::Int) => t }}} I think this error is still bogus, because ghc should not have inferred {{{ f2 :: forall t. (?loc::t) => t }}} in the first place. It should have inferred {{{ f2 :: (?loc::Int) => Int }}} which is a valid instantiation of the partial signature, and so should be OK. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11016#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler