#12081: TypeInType Compile-time Panic -------------------------------------+------------------------------------- Reporter: MichaelK | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1-rc4 Resolution: | Keywords: TypeInType Operating System: Unknown/Multiple | Architecture: Type of failure: Compile-time | Unknown/Multiple crash | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by goldfire): * keywords: => TypeInType Comment: GHC should never panic, so this is certainly a bug. However, your program is not type-correct: any type that classifies a runtime value must have kind `Type` (same as `*`). The type of `f` is given as `(a :: T n)`, which has kind `T n`, not `Type`. I'm not sure what your goal is here, but even without the panic, this program would be rejected by GHC. Thanks for reporting! -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12081#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler

#12081: TypeInType Compile-time Panic -------------------------------------+------------------------------------- Reporter: MichaelK | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1-rc4 Resolution: | Keywords: TypeInType Operating System: Unknown/Multiple | Architecture: Type of failure: Compile-time | Unknown/Multiple crash | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by MitchellSalad): I happened to hit this same panic with a simpler example: {{{#!hs {-# LANGUAGE DataKinds #-} {-# LANGUAGE ExistentialQuantification #-} {-# LANGUAGE KindSignatures #-} {-# LANGUAGE TypeInType #-} data Foo = forall (x :: Foo). Bar x }}} fails with: {{{ ghc: panic! (the 'impossible' happened) (GHC version 8.0.1 for x86_64-unknown-linux): isInjectiveTyCon sees a TcTyCon Foo }}} Without -XTypeInType, it fails with: {{{ foo.hs:5:25: error: • Type constructor ‘Foo’ cannot be used here (Perhaps you intended to use TypeInType) • In the kind ‘Foo’ In the definition of data constructor ‘Bar’ In the data declaration for ‘Foo’ }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12081#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler

#12081: TypeInType Compile-time Panic -------------------------------------+------------------------------------- Reporter: MichaelK | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1-rc4 Resolution: | Keywords: TypeInType Operating System: Unknown/Multiple | Architecture: Type of failure: Compile-time | Unknown/Multiple crash | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by Simon Peyton Jones ): In [changeset:"853cdaea7f8724cd071f4fa7ad6c5377a2a8a6e4/ghc" 853cdaea/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="853cdaea7f8724cd071f4fa7ad6c5377a2a8a6e4" Test Trac #12081 }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12081#comment:5 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler