Skip to content

GitLab

  • Projects
  • Groups
  • Snippets
  • Help
    • Loading...
  • Help
    • Help
    • Support
    • Community forum
    • Submit feedback
  • Sign in / Register
GHC
GHC
  • Project overview
    • Project overview
    • Details
    • Activity
    • Releases
  • Repository
    • Repository
    • Files
    • Commits
    • Branches
    • Tags
    • Contributors
    • Graph
    • Compare
    • Locked Files
  • Issues 4,323
    • Issues 4,323
    • List
    • Boards
    • Labels
    • Service Desk
    • Milestones
    • Iterations
  • Merge Requests 362
    • Merge Requests 362
  • Requirements
    • Requirements
    • List
  • CI / CD
    • CI / CD
    • Pipelines
    • Jobs
    • Schedules
  • Security & Compliance
    • Security & Compliance
    • Dependency List
    • License Compliance
  • Operations
    • Operations
    • Incidents
    • Environments
  • Analytics
    • Analytics
    • CI / CD
    • Code Review
    • Insights
    • Issue
    • Repository
    • Value Stream
  • Wiki
    • Wiki
  • Snippets
    • Snippets
  • Members
    • Members
  • Collapse sidebar
  • Activity
  • Graph
  • Create a new issue
  • Jobs
  • Commits
  • Issue Boards
  • Glasgow Haskell Compiler
  • GHCGHC
  • Issues
  • #14117

Closed
Open
Opened Aug 15, 2017 by Ben Gamari@bgamari🐢Maintainer

stg-lint fails on unlifted-type join point binding

While validating GHC with BuildFlavour=devel2 and -dstg-lint I found that the linter chokes when it finds a join point of unlifted type (like this one from the Binary module),

ghc-stage1: panic! (the 'impossible' happened)
  (GHC version 8.3.20170815 for x86_64-unknown-linux):
          *** Stg Lint ErrMsgs: in Stg2Stg ***
  <no location info>: warning:
       [RHS of $j_sDSL :: (# State# RealWorld, () #)]
      Let(rec) binder ‘$j_sDSL’ has unlifted type ‘(# State# RealWorld,
                                                      () #)’
      RHS: \r []
               src<compiler/utils/Binary.hs:516:9-17>
               src<compiler/utils/Binary.hs:(516,21)-(518,26)>
               src<compiler/utils/Binary.hs:260:1-45>
               src<compiler/utils/Binary.hs:(239,1)-(246,34)>
               case readIntArray# [ww_sDSF 0# w1_sDSJ] of {
...

If I'm not mistaken there is no problem with join points having unlifted type (see Note [CoreSyn let/app invariant]). We just need to update the STG linter appropriately.

Trac metadata
Trac field Value
Version 8.2.1
Type Bug
TypeOfFailure OtherFailure
Priority normal
Resolution Unresolved
Component Compiler
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system
Architecture
Assignee
Assign to
8.4.1
Milestone
8.4.1 (Past due)
Assign milestone
Time tracking
None
Due date
None
Reference: ghc/ghc#14117