[GHC] #14127: -fignore-interface-pragmas and -fspecialise do not go well together

[GHC]

#14127: -fignore-interface-pragmas and -fspecialise do not go well together
-------------------------------------+-------------------------------------
        Reporter:  lspitzner         |                Owner:  (none)
            Type:  bug               |               Status:  closed
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.0.2
      Resolution:  fixed             |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  crash or panic                     |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------
Changes (by RyanGlScott):

 * status:  infoneeded => closed
 * resolution:   => fixed


Comment:

 After reading the source code some more, I believe this was properly fixed
 in GHC 8.2. Specifically, in commit
 d49b2bb21691892ca6ac8f2403e31f2a5e53feb3 (Allow top-level string literals
 in Core (#8472)). That patch made the
 [http://git.haskell.org/ghc.git/blobdiff/a2a67b77c3048713541d1ed96ec0b95fb2542f9a..d49b2bb21691892ca6ac8f2403e31f2a5e53feb3:/compiler/coreSyn/CorePrep.hs
 following change]:

 {{{#!diff
 diff --git a/compiler/coreSyn/CorePrep.hs b/compiler/coreSyn/CorePrep.hs
 index c93a121..fb650f6 100644 (file)
 --- a/compiler/coreSyn/CorePrep.hs
 +++ b/compiler/coreSyn/CorePrep.hs
 @@ -1168,7 +1168,9 @@ deFloatTop (Floats _ floats)
    = foldrOL get [] floats
    where
      get (FloatLet b) bs = occurAnalyseRHSs b : bs
 -    get b            _  = pprPanic "corePrepPgm" (ppr b)
 +    get (FloatCase var body _) bs  =
 +      occurAnalyseRHSs (NonRec var body) : bs
 +    get b _ = pprPanic "corePrepPgm" (ppr b)

      -- See Note [Dead code in CorePrep]
      occurAnalyseRHSs (NonRec x e) = NonRec x
 (occurAnalyseExpr_NoBinderSwap e)
 }}}

 Before, `get` was being called on a `FloatCase`, which is the only
 constructor that could have given the output `[True]
 $s$fSelectorMetaMetaSel_a = "_dconf_dump_annotations"#`. But now that this
 case is covered properly, the issue appears to have gone away. So I'll opt
 to close this issue, since I can't reproduce the problem on 8.2, and
 coming up with a minimal regression test doesn't seem feasible.

 Please feel free to re-open the issue if you come across the same panic on
 GHC 8.2 or later.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14127#comment:5>
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