Skip to content

GitLab

  • Menu
Projects Groups Snippets
    • Loading...
  • Help
    • Help
    • Support
    • Community forum
    • Submit feedback
  • Sign in / Register
  • GHC GHC
  • Project information
    • Project information
    • Activity
    • Labels
    • Members
  • Repository
    • Repository
    • Files
    • Commits
    • Branches
    • Tags
    • Contributors
    • Graph
    • Compare
    • Locked Files
  • Issues 4,842
    • Issues 4,842
    • List
    • Boards
    • Service Desk
    • Milestones
    • Iterations
  • Merge requests 456
    • Merge requests 456
  • CI/CD
    • CI/CD
    • Pipelines
    • Jobs
    • Schedules
    • Test Cases
  • Deployments
    • Deployments
    • Releases
  • Analytics
    • Analytics
    • CI/CD
    • Code review
    • Insights
    • Issue
    • Repository
    • Value stream
  • Wiki
    • Wiki
  • Snippets
    • Snippets
  • Activity
  • Graph
  • Create a new issue
  • Jobs
  • Commits
  • Issue Boards
Collapse sidebar
  • Glasgow Haskell Compiler
  • GHCGHC
  • Issues
  • #11399

Closed
Open
Created Jan 10, 2016 by Ryan Scott@RyanGlScottMaintainer

Ill-kinded instance head involving -XTypeInType can invoke GHC panic

This code:

{-# LANGUAGE FlexibleInstances, TypeInType #-}
module FvProvFallsIntoAHole where

import Data.Kind

newtype UhOh (k :: * -> *) (a :: k *) = UhOh (k *)
instance Functor k => Functor (UhOh k) where

produces this GHC panic:

$ /opt/ghc/head/bin/ghc FvProvFallsIntoAHole.hs
[1 of 1] Compiling FvProvFallsIntoAHole ( FvProvFallsIntoAHole.hs, FvProvFallsIntoAHole.o )
ghc: panic! (the 'impossible' happened)
  (GHC version 8.1.20160108 for x86_64-unknown-linux):
        fvProv falls into a hole {aq6}

Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug
Trac metadata
Trac field Value
Version 8.1
Type Bug
TypeOfFailure OtherFailure
Priority normal
Resolution Unresolved
Component Compiler (Type checker)
Test case
Differential revisions
BlockedBy
Related
Blocking
CC goldfire
Operating system
Architecture
To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information
Assignee
Assign to
Time tracking