Skip to content

GitLab

  • Menu
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 4,869
    • Issues 4,869
    • 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
    • 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 Compiler
  • GHCGHC
  • Issues
  • #14983
Closed
Open
Created Mar 29, 2018 by Icelandjack@IcelandjackReporter

Have custom type errors imply Void

This is a very minor issue, but TypeError (CustomTypeErrors) should entail a constraint like

import Data.Void

class (forall x. x) => No where
  no :: Void

so users don't have to use undefined or error ..:

instance TypeError (Text "Can't show functions") => Show (a -> b) where
  show :: (a -> b) -> String
  show = no & absurd
Edited Mar 10, 2019 by Icelandjack
To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information
Assignee
Assign to
Time tracking