[GHC] #11440: GHC.Prim does not export Constraint
#11440: GHC.Prim does not export Constraint -------------------------------------+------------------------------------- Reporter: thomie | Owner: Type: bug | Status: new Priority: highest | Milestone: 8.0.1 Component: Compiler | Version: 8.0.1-rc1 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: -------------------------------------+------------------------------------- This code from the `effect-monad` library worked in ghc-7.10, but fails with ghc-8.0.1-rc1: {{{ {-# LANGUAGE TypeFamilies, ConstraintKinds, PolyKinds #-} module Control.Effect.Cond where import GHC.Prim class Cond (m :: k -> * -> *) where type AltInv m (s :: k) (t :: k) :: Constraint }}} It seems one now needs to import `Constraint` from `GHC.Exts`. This should be mentioned in the migration guide (https://ghc.haskell.org/trac/ghc/wiki/Migration/8.0), together with any other breaking changes there might be from the kind equalities patch (6746549772c5cc0ac66c0fce562f297f4d4b80a2). -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11440 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#11440: GHC.Prim does not export Constraint -------------------------------------+------------------------------------- Reporter: thomie | Owner: Type: bug | Status: new Priority: highest | Milestone: 8.0.1 Component: Compiler | Version: 8.0.1-rc1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by goldfire): As I understand it, `GHC.Exts` is the One Official Place from where to import magic GHC gubbins, so I didn't worry too much about moving things around behind the scenes. I'll add a note to the migration guide. There should not be other breakages from the kind equalities patch. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11440#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#11440: GHC.Prim does not export Constraint -------------------------------------+------------------------------------- Reporter: thomie | Owner: Type: bug | Status: closed Priority: highest | Milestone: 8.0.1 Component: Compiler | Version: 8.0.1-rc1 Resolution: fixed | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by goldfire): * status: new => closed * resolution: => fixed Comment: Updated the wiki page. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11440#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#11440: GHC.Prim does not export Constraint -------------------------------------+------------------------------------- Reporter: thomie | Owner: Type: bug | Status: closed Priority: highest | Milestone: 8.0.1 Component: Compiler | Version: 8.0.1-rc1 Resolution: fixed | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by thomie): Thank you. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11440#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
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