[GHC] #15867: STG scope error

[GHC]

#15867: STG scope error
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        Reporter:  csabahruska       |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.7
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Description changed by csabahruska:

Old description:

> StgRhsClosure can contain duplicated names in its free variable and
> argument list.
>
> Example bug: libraries/integer-gmp/src/GHC/Integer/Type.hs
>
> GHC HEAD and 8.2.2 has this issue.
>
> I have not checked with other versions.
>
> I've extended the STG linter to do scope checking. See the patch
> attached.
>
> To reproduce:
>  * patch GHC head: `git apply StgScopeCheck.patch`
>  * make sure every compiled stg is linted: add `-dstg-lint` to
> GhcStage2HcOpts GhcLibHcOpts GhcRtsHcOpts config vars
>  * compile GHC HEAD
>
> Background info:
>  I've found this issue because I'm using GHC as a Haskell fronted for my
> whole program compiler project. I work on The GRIN Compiler
> (https://github.com/grin-tech) where GHC/GRIN compiles STG to GRIN.

New description:

 StgRhsClosure can contain duplicated names in its free variable and
 argument list.

 Example bug: libraries/integer-gmp/src/GHC/Integer/Type.hs

 GHC HEAD and 8.2.2 has this issue.

 I have not checked with other versions.

 I've extended the STG linter to do scope checking. See the patch attached.

 To reproduce:
  * patch GHC head: `git apply StgScopeCheck.patch`
  * make sure every compiled stg is linted: add the following to
 `mk/build.mk`\\
 {{{
 GhcStage2HcOpts += -dstg-lint
 GhcLibHcOpts += -dstg-lint
 GhcRtsHcOpts += -dstg-lint
 }}}
  * compile GHC HEAD

 Background info:
  I've found this issue because I'm using GHC as a Haskell fronted for my
 whole program compiler project. I work on The GRIN Compiler
 (https://github.com/grin-tech) where GHC/GRIN compiles STG to GRIN.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15867#comment:1>
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