[GHC] #11976: Error message mentions impredicative polymorphism
#11976: Error message mentions impredicative polymorphism -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.3 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: -------------------------------------+------------------------------------- When we apply `Lens` to too many arguments in the `:kind` command we get a sensible error message {{{ ghci> type Lens s a = forall f. Functor f => (a -> f a) -> (s -> f s) ghci> :kind Lens _ _ Lens _ _ :: * ghci> :kind Lens _ _ _ <interactive>:1:1: error: • Expecting one fewer argument to ‘Lens t0 t1’ Expected kind ‘k0 -> k1’, but ‘Lens t0 t1’ has kind ‘*’ • In the type ‘Lens _ _ _’ }}} but use the same in a type signature or annotation and it complains about impredicative polymorphism {{{ ghci> :t undefined :: Lens _ _ _ <interactive>:1:1: error: • Illegal polymorphic type: Lens _ _1 GHC doesn't yet support impredicative polymorphism • In the expression: undefined :: Lens _ _ _ ghci> a :: Lens _ _ _; a = undefined <interactive>:6:1: error: Illegal polymorphic type: Lens _ _1 GHC doesn't yet support impredicative polymorphism }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11976 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#11976: Error message mentions impredicative polymorphism
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Reporter: Iceland_jack | Owner:
Type: bug | Status: new
Priority: normal | Milestone:
Component: Compiler | Version: 7.10.3
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: |
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Comment (by Simon Peyton Jones
#11976: Error message mentions impredicative polymorphism -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: Type: bug | Status: merge Priority: normal | Milestone: 8.0.2 Component: Compiler | Version: 7.10.3 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: partial- | sigs/should_fail/T11976 Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by simonpj): * status: new => merge * testcase: => partial-sigs/should_fail/T11976 * milestone: => 8.0.2 Comment: This fixes a real bug, and I don't think it'll break anything, but I'm doubtful about merging anything after the final release candidate. So let's leave this for the patch release. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11976#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#11976: Error message mentions impredicative polymorphism -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: Type: bug | Status: closed Priority: normal | Milestone: 8.0.2 Component: Compiler | Version: 7.10.3 Resolution: fixed | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: partial- | sigs/should_fail/T11976 Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by bgamari): * status: merge => closed * resolution: => fixed Comment: Merged to `ghc-8.0` as 7a69acc846e19562a0e07f8f5f9a5c01f8084e83. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11976#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
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