Re: [GHC] #11715: Constraint vs *

#11715: Constraint vs * -------------------------------------+------------------------------------- Reporter: bgamari | Owner: goldfire Type: bug | Status: new Priority: high | Milestone: Component: Compiler (Type | Version: 8.0.1-rc1 checker) | Keywords: Typeable, Resolution: | LevityPolymorphism, Roles Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D3316 Wiki Page: | -------------------------------------+------------------------------------- Comment (by Simon Peyton Jones ): In [changeset:"c5d31df70b16dc346b5860077c8bbe585ddb7a78/ghc" c5d31df7/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="c5d31df70b16dc346b5860077c8bbe585ddb7a78" Treat isConstraintKind more consistently It turned out that we were not being consistent about our use of isConstraintKind. It's delicate, because the typechecker treats Constraint and Type as /distinct/, whereas they are the /same/ in the rest of the compiler (Trac #11715). And had it wrong, which led to Trac #15412. This patch does the following: * Rename isConstraintKind to tcIsConstraintKind returnsConstraintKind to tcReturnsConstraintKind to emphasise that they use the 'tcView' view of types. * Move these functions, and some related ones (tcIsLiftedTypeKind), from Kind.hs, to group together in Type.hs, alongside isPredTy. It feels very unsatisfactory that these 'tcX' functions live in Type, but it happens because isPredTy is called later in the compiler too. But it's a consequence of the 'Constraint vs Type' dilemma. }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11715#comment:81 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler