Skip to content
GitLab
Projects Groups Topics Snippets
  • /
  • Help
    • Help
    • Support
    • Community forum
    • Submit feedback
  • Register
  • Sign in
  • GHC GHC
  • Project information
    • Project information
    • Activity
    • Labels
    • Members
  • Repository
    • Repository
    • Files
    • Commits
    • Branches
    • Tags
    • Contributor statistics
    • Graph
    • Compare revisions
    • Locked files
  • Issues 5.5k
    • Issues 5.5k
    • List
    • Boards
    • Service Desk
    • Milestones
    • Iterations
  • Merge requests 631
    • Merge requests 631
  • CI/CD
    • CI/CD
    • Pipelines
    • Jobs
    • Artifacts
    • Schedules
    • Test cases
  • Deployments
    • Deployments
    • Releases
  • Packages and registries
    • Packages and registries
    • Model experiments
  • Analytics
    • Analytics
    • 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
  • #12373

Type error but types match

> unboxedsums git:(prim_sums_rebase_5) x cat primop_bug.hs
{-# LANGUAGE MagicHash, ScopedTypeVariables, UnboxedTuples #-}

module Main where

import GHC.MVar
import GHC.Prim
import GHC.Types

main :: IO ()
main = IO (\rw -> newMVar# rw) >> return ()

> unboxedsums git:(prim_sums_rebase_5) x ghc-stage1 primop_bug.hs -ddump-stg -ddump-cmm -ddump-to-file -fforce-recomp -dumpdir primop_fails -O -fprint-explicit-kinds
[1 of 1] Compiling Main             ( primop_bug.hs, primop_bug.o )

primop_bug.hs:10:19: error:
    • Couldn't match a lifted type with an unlifted type
      Expected type: (# State# RealWorld, MVar# RealWorld a0 #)
        Actual type: (# State# RealWorld, MVar# RealWorld a0 #)
    • In the expression: newMVar# rw
      In the first argument of ‘IO’, namely ‘(\ rw -> newMVar# rw)’
      In the first argument of ‘(>>)’, namely ‘IO (\ rw -> newMVar# rw)’

Tried with HEAD, 8.0.1.

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
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