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#12024: GHC leaks GHC.Prim.~# into type -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: Type: feature | Status: new request | Priority: normal | Milestone: Component: Compiler | Version: 7.10.3 (Type checker) | 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: -------------------------------------+------------------------------------- {{{#!hs data A a where X :: A [xxx] pattern X' = X }}} the inferred type of which is {{{ pattern X' :: () => t GHC.Prim.~# [xxx] => A t }}} Casts use unlifted equality as I understand it, but lifted would present a nicer UI: {{{#!hs pattern X' :: () => t ~> [xxx] => A t pattern X' = X }}} In my own code this means I get the following monster {{{#!hs pattern MkArr :: () => (GetTy a, GetTy b, GetTy t, a GHC.Prim.~# 'Sca ('Number 'I32), b GHC.Prim.~# 'Sca a1, t GHC.Prim.~# 'Arr a1, GetSca a1) => Exp a -> Id -> Exp b -> Exp t }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12024 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler