[GHC] #12742: Instantiation of invisible type family arguments is too eager
#12742: Instantiation of invisible type family arguments is too eager -------------------------------------+------------------------------------- Reporter: goldfire | Owner: goldfire Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: GHC rejects Unknown/Multiple | valid program Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- This module looks, to me, like it should be accepted: {{{ {-# LANGUAGE TypeInType, RankNTypes, TypeFamilies #-} module Bug where import Data.Kind type family F :: forall k2. (k1, k2) data T :: (forall k2. (Bool, k2)) -> Type type S = T F }}} But it's not. The problem is that `TcHsType.handle_tyfams` eagerly instantiates ''all'' invisible arguments to a type family at every occurrence. Instead, it should instantiate only those that are counted in the TF's arity -- that is, those "before the colon". Will fix. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12742 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#12742: Instantiation of invisible type family arguments is too eager -------------------------------------+------------------------------------- Reporter: goldfire | Owner: goldfire Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 Resolution: | Keywords: TypeInType Operating System: Unknown/Multiple | Architecture: Type of failure: GHC rejects | Unknown/Multiple valid program | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by simonpj): * keywords: => TypeInType -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12742#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#12742: Instantiation of invisible type family arguments is too eager -------------------------------------+------------------------------------- Reporter: goldfire | Owner: goldfire Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 Resolution: | Keywords: TypeInType Operating System: Unknown/Multiple | Architecture: Type of failure: GHC rejects | Unknown/Multiple valid program | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by goldfire): This is fixed now. Will add a regression test. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12742#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#12742: Instantiation of invisible type family arguments is too eager
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Reporter: goldfire | Owner: goldfire
Type: bug | Status: new
Priority: normal | Milestone:
Component: Compiler | Version: 8.0.1
Resolution: | Keywords: TypeInType
Operating System: Unknown/Multiple | Architecture:
Type of failure: GHC rejects | Unknown/Multiple
valid program | Test Case:
Blocked By: | Blocking:
Related Tickets: | Differential Rev(s):
Wiki Page: |
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Comment (by Ben Gamari
#12742: Instantiation of invisible type family arguments is too eager -------------------------------------+------------------------------------- Reporter: goldfire | Owner: goldfire Type: bug | Status: closed Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 Resolution: fixed | Keywords: TypeInType Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: GHC rejects | Test Case: valid program | dependent/should_compile/T12742 Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by RyanGlScott): * testcase: => dependent/should_compile/T12742 * status: new => closed * resolution: => fixed Comment: As noted in comment:2 and comment:3, this has been fixed, and a regression test has been added. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12742#comment:4 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
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