#11291: DfltProb1(optasm): panic CoreToStg.myCollectArgs -------------------------------------+------------------------------------- Reporter: thomie | Owner: Type: bug | Status: new Priority: highest | Milestone: 8.0.1 Component: Compiler | Version: 7.11 (CodeGen) | Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: Compile-time | Test Case: crash | typecheck/should_compile/DfltProb1 | (optasm) Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by bgamari): * failure: None/Unknown => Compile-time crash * component: Compiler => Compiler (CodeGen) Old description:

The program looks like this: {{{ module DfltProb1 where

import Control.Monad.ST import Prelude hiding (traverse)

traverse :: a -> ST s [a] traverse = undefined

-- WORKS with signature test :: Num a => [a] test = runST (traverse 1)

main = print test }}}

This is the failure: {{{ $ ghc-7.11.20151225 -O DfltProb1.hs ghc-stage2: panic! (the 'impossible' happened) (GHC version 7.11.20151224 for x86_64-unknown-linux): CoreToStg.myCollectArgs (case traverse of _ [Occ=Dead] { }) realWorld# }}}

New description: The program looks like this: {{{#!hs module DfltProb1 where import Control.Monad.ST import Prelude hiding (traverse) traverse :: a -> ST s [a] traverse = undefined -- WORKS with signature test :: Num a => [a] test = runST (traverse 1) main = print test }}} This is the failure: {{{ $ ghc-7.11.20151225 -O DfltProb1.hs ghc-stage2: panic! (the 'impossible' happened) (GHC version 7.11.20151224 for x86_64-unknown-linux): CoreToStg.myCollectArgs (case traverse of _ [Occ=Dead] { }) realWorld# }}} -- Comment: I believe this is fixed on `master`. I have a suspicion that this is due to d990354473239943d83ee90f8906f3737b53fe65. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11291#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler

#11291: DfltProb1(optasm): panic CoreToStg.myCollectArgs -------------------------------------+------------------------------------- Reporter: thomie | Owner: Type: bug | Status: new Priority: highest | Milestone: 8.0.1 Component: Compiler | Version: 7.11 (CodeGen) | Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: Compile-time | Test Case: crash | typecheck/should_compile/DfltProb1 | (optasm) Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by thomie): Maybe you forgot `-O`, or `-fforce-recomp`. I just tried with 7.11.20151229 from https://launchpad.net/~hvr/+archive/ubuntu/ghc, and I can still reproduce. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11291#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler

#11291: DfltProb1(optasm): panic CoreToStg.myCollectArgs -------------------------------------+------------------------------------- Reporter: thomie | Owner: Type: bug | Status: new Priority: highest | Milestone: 8.0.1 Component: Compiler | Version: 7.11 (CodeGen) | Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: Compile-time | Test Case: crash | typecheck/should_compile/DfltProb1 | (optasm) Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by thomie): Hmm, Harbormaster also fails on `TEST=DfltProb1 WAY=optasm` (and a bunch of other tests): https://phabricator.haskell.org/D1652#50905 -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11291#comment:5 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler

#11291: DfltProb1(optasm): panic CoreToStg.myCollectArgs -------------------------------------+------------------------------------- Reporter: thomie | Owner: simonpj Type: bug | Status: new Priority: highest | Milestone: 8.0.1 Component: Compiler | Version: 7.11 (CodeGen) | Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: Compile-time | Test Case: crash | typecheck/should_compile/DfltProb1 | (optasm) Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by Simon Peyton Jones ): In [changeset:"f3cc34568b13abb29de7b54a5f657681e9e116ca/ghc" f3cc345/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="f3cc34568b13abb29de7b54a5f657681e9e116ca" Add strictness for runRW# runRW# isn't inlined until CorePrep, so it's good to expose its strictness. Moreover, if we don't we can get obscure failures in coreToStg; see Note [runRW arg] in CorePrep. This fixes Trac #11291, and makes DfltProb1 compile with -O always in order to expose it more vigorously }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11291#comment:7 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler

#11291: DfltProb1(optasm): panic CoreToStg.myCollectArgs -------------------------------------+------------------------------------- Reporter: thomie | Owner: simonpj Type: bug | Status: closed Priority: highest | Milestone: 8.0.1 Component: Compiler | Version: 7.11 (CodeGen) | Resolution: fixed | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: Compile-time | Test Case: crash | typecheck/should_compile/DfltProb1 | (optasm) Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by hvr): Replying to [comment:8 simonpj]:

I've fixed this one.

I assume this is supposed to be merged to the GHC-8.0 branch as well? -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11291#comment:9 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler