Fix type error in MkZipCfg

- Fixes a bug introduced with the patch named
  'check for unreachable code only with -DDEBUG'
- Breakage occured only without -DDEBUG (which is 'valdiate's default!)

diff --git a/compiler/cmm/MkZipCfg.hs b/compiler/cmm/MkZipCfg.hs
index dc19197..8b0284c 100644 (file)
--- a/compiler/cmm/MkZipCfg.hs
+++ b/compiler/cmm/MkZipCfg.hs
@@ -327,7 +327,7 @@ note_this_code_becomes_unreachable = u
                                     -- Note [Branch follows branch]
           u tail = fail ("unreachable code: " ++ showSDoc (ppr tail))
 #else
-note_this_code_becomes_unreachable = return ()
+note_this_code_becomes_unreachable _ = return ()
 #endif
 
 {-