#7165: "match_co bailing out" messages and compiler crash
--------------------------------+-------------------------------------------
Reporter: alang | Owner:
Type: bug | Status: new
Priority: normal | Component: Compiler
Version: 7.7 | Keywords:
Os: Linux | Architecture: x86_64 (amd64)
Failure: Compile-time crash | Testcase:
Blockedby: | Blocking:
Related: |
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{{{
$ cat > Blah.hs
{-# LANGUAGE GADTs #-}
module Blah where
blah :: (dd ~ (Double, Double)) => dd -> dd
blah (ax, bx)
| ax < bx = blah (bx, ax)
| otherwise = (0,0)
$ cat > Meh.hs
module Meh where
import Blah
meh = blah (0,0)
}}}
If we compile with -O2, in 2 separate calls to ghc, we get:
{{{
$ ghc -O2 Blah.hs
[1 of 1] Compiling Blah ( Blah.hs, Blah.o )
match_co baling out
<(ghc-prim:GHC.Types.Double{(w) tc 3u},
ghc-prim:GHC.Types.Double{(w) tc 3u})>
match_co baling out
<(ghc-prim:GHC.Types.Double{(w) tc 3u},
ghc-prim:GHC.Types.Double{(w) tc 3u})>
match_co baling out
<(ghc-prim:GHC.Types.Double{(w) tc 3u},
ghc-prim:GHC.Types.Double{(w) tc 3u})>
match_co baling out
<(ghc-prim:GHC.Types.Double{(w) tc 3u},
ghc-prim:GHC.Types.Double{(w) tc 3u})>
match_co baling out
<(ghc-prim:GHC.Types.Double{(w) tc 3u},
ghc-prim:GHC.Types.Double{(w) tc 3u})>
match_co baling out
<(ghc-prim:GHC.Types.Double{(w) tc 3u},
ghc-prim:GHC.Types.Double{(w) tc 3u})>
$ ghc -O2 Meh.hs
[2 of 2] Compiling Meh ( Meh.hs, Meh.o )
ghc: panic! (the 'impossible' happened)
(GHC version 7.4.2 for x86_64-unknown-linux):
tcIfaceType
Refl
(ghc-prim:GHC.Types.Double{(w) tc 3u},
ghc-prim:GHC.Types.Double{(w) tc 3u})
Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug
}}}
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7165>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler
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