#12844: No Skolem Info with PartialTypeSignatures -------------------------------------+------------------------------------- Reporter: crockeea | Owner: Type: bug | Status: closed Priority: normal | Milestone: 8.0.2 Component: Compiler | Version: 8.0.1 Resolution: fixed | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: Compile-time | Test Case: partial- crash or panic | sigs/should_compile/T12844 Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by bgamari): * status: merge => closed * resolution: => fixed * milestone: => 8.0.2 @@ -3,1 +3,1 @@ - {{{ + {{{#!hs New description: The following program triggers a panic: {{{#!hs {-# LANGUAGE DataKinds #-} {-# LANGUAGE PartialTypeSignatures #-} {-# LANGUAGE PolyKinds #-} {-# LANGUAGE TypeFamilies #-} {-# LANGUAGE TypeOperators #-} barWraper :: ('(r,r') ~ Head rngs, Foo rngs) => FooData rngs barWraper = bar bar :: (_) => FooData rngs bar = foo data FooData rngs class Foo xs where foo :: (Head xs ~ '(r,r')) => FooData xs type family Head (xs :: [k]) where Head (x ': xs) = x }}} {{{

ghci NoSkolem.hs [1 of 1] Compiling Main ( NoSkolem.hs, NoSkolem.o )

NoSkolem.hs:8:13: error:ghc: panic! (the 'impossible' happened) (GHC version 8.0.1 for x86_64-unknown-linux): No skolem info: k_aYV[sk] }}} I haven't tested with 8.0.2 or head. -- Comment: Merged to `ghc-8.0` as 4212674ba92971734eec064809f8e1a45bca992a. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12844#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler