[GHC] #7696: Another kindFunResult panic
#7696: Another kindFunResult panic -----------------------------+---------------------------------------------- Reporter: nwf | Owner: Type: bug | Status: new Priority: normal | Component: Compiler Version: 7.6.2 | Keywords: Os: Unknown/Multiple | Architecture: Unknown/Multiple Failure: None/Unknown | Blockedby: Blocking: | Related: -----------------------------+---------------------------------------------- While working at the GHCi prompt, I left off a pair of parens, yielding: {{{
import Control.Applicative import Control.Monad.Trans :type \x -> (either (fmap Right) id) <$> lift $ x ghc: panic! (the 'impossible' happened) (GHC version 7.7.20130214 for x86_64-unknown-linux): kindFunResult <<details unavailable>>
Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug }}} Replacing `<$> lift $ x` with `<$> (lift $ x)`, which is what I'd meant, makes everybody happier. But as this happens in both 7.6.2 and 7.7.20130214, I thought I should do what it says and report it. Thanks! -- Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/7696 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#7696: Another kindFunResult panic -----------------------------+---------------------------------------------- Reporter: nwf | Owner: Type: bug | Status: new Priority: normal | Component: Compiler Version: 7.6.2 | Keywords: Os: Unknown/Multiple | Architecture: Unknown/Multiple Failure: None/Unknown | Blockedby: Blocking: | Related: -----------------------------+---------------------------------------------- Comment(by monoidal): There are two different issues here: one causes panic in HEAD, the other in 7.6.2. Panic in HEAD (7.6 correctly reports error): {{{ f1 :: (m a, t m) f1 = undefined f2 :: ((), m ()) f2 = f1 }}} Panic in 7.6 (HEAD correctly reports error): {{{ lift :: m a -> t m a lift = undefined k :: f (Either Int Int) k = lift }}} The second one is probably the same cause as #7368, which was left unfixed in 7.6. -- Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/7696#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#7696: Another kindFunResult panic
-----------------------------+----------------------------------------------
Reporter: nwf | Owner:
Type: bug | Status: new
Priority: normal | Component: Compiler
Version: 7.6.2 | Keywords:
Os: Unknown/Multiple | Architecture: Unknown/Multiple
Failure: None/Unknown | Blockedby:
Blocking: | Related:
-----------------------------+----------------------------------------------
Comment(by simonpj@…):
commit c969cc3d2cfcd31fc8e7222c7c9ec116191c136b
{{{
Author: Simon Peyton Jones
#7696: Another kindFunResult panic ------------------------------------------+--------------------------------- Reporter: nwf | Owner: Type: bug | Status: closed Priority: normal | Milestone: Component: Compiler | Version: 7.6.2 Resolution: fixed | Keywords: Os: Unknown/Multiple | Architecture: Unknown/Multiple Failure: None/Unknown | Difficulty: Unknown Testcase: typecheck/should_fail/T7696 | Blockedby: Blocking: | Related: ------------------------------------------+--------------------------------- Changes (by simonpj): * cc: dimitris@… (added) * difficulty: => Unknown * status: new => closed * resolution: => fixed * testcase: => typecheck/should_fail/T7696 Comment: Excellent point! Actually this bug revealed a pretty significant shortcoming in the constraint solver (see the commit message). Fortunately, I found rather a neat solution, so all is good now. Thanks for identifying it so compactly. Simon -- Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/7696#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
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