#11376: Inconsistent specified type variables among functions and datatypes/classes when using -XTypeApplications -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: goldfire Type: bug | Status: new Priority: normal | Milestone: Component: Compiler (Type | Version: 8.1 checker) | Keywords: Resolution: | TypeApplications Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: Other | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by goldfire): You're talking about `Note [Instantiate when inferring a type]` in !TcBinds. Yes. When we infer a type, we instantiate. The Note has the details, but this design makes it so that values with inferred types never have any variables available for type application. This is good. With `:type`, though, we don't want to instantiate, because doing so might change specified variables to invisible ones. Or in cases like `forall a. (a ~ Int) => ...`, instantiating and then solving will actually get rid of a variable. Instantiating ''when there are no more specified variables'' isn't ruinous, but I'm sure implementing the special case will cause confusion. Given that this is, essentially, a pretty-printing issue, maybe it should be controlled by `-fprint-explicit-foralls`? With the flag set, we never instantiate. Otherwise, we always instantiate. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11376#comment:19 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler