Skip to content
GitLab
Projects Groups Snippets
  • /
  • 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 5,243
    • Issues 5,243
    • List
    • Boards
    • Service Desk
    • Milestones
    • Iterations
  • Merge requests 567
    • Merge requests 567
  • CI/CD
    • CI/CD
    • Pipelines
    • Jobs
    • Schedules
    • Test Cases
  • Deployments
    • Deployments
    • Releases
  • Analytics
    • Analytics
    • Value stream
    • CI/CD
    • Code review
    • Insights
    • Issue
    • Repository
  • Wiki
    • Wiki
  • Snippets
    • Snippets
  • Activity
  • Graph
  • Create a new issue
  • Jobs
  • Commits
  • Issue Boards
Collapse sidebar
  • Glasgow Haskell CompilerGlasgow Haskell Compiler
  • GHCGHC
  • Issues
  • #2516
Closed
Open
Issue created Aug 14, 2008 by josef@trac-josef

Panic in typechecker when checking rules

GHC will panic when given either of the following modules. The error messages are somewhat different for the two different rules.

module GHCBug1 where

foo :: (forall a . a -> f a) -> f Int
foo f = f undefined

{-# RULES
    "bug1"
    forall (g :: a -> f a) .
    head (foo g) = undefined
 #-}
module GHCBug2 where

foo :: (forall a . a -> f a) -> f Int
foo f = f undefined

{-# RULES
    "bug2"
    forall (g :: forall a . a -> f a) .
    head (foo g) = undefined
 #-}
Trac metadata
Trac field Value
Version 6.8.2
Type Bug
TypeOfFailure OtherFailure
Priority normal
Resolution Unresolved
Component Compiler (Type checker)
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
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