X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2FcoreSyn%2FCoreFVs.lhs;h=3ff583ee2006c02f5a2c3c1ab2f43f80b1be685c;hp=f94f61d25ebd30ea2a1fd0578de933deb5b7a283;hb=6a944ae7fe1e8e2e456c68717188463263f8978f;hpb=72462499b891d5779c19f3bda03f96e24f9554ae

diff --git a/compiler/coreSyn/CoreFVs.lhs b/compiler/coreSyn/CoreFVs.lhs
index f94f61d..3ff583e 100644
--- a/compiler/coreSyn/CoreFVs.lhs
+++ b/compiler/coreSyn/CoreFVs.lhs
@@ -416,8 +416,11 @@ idRuleRhsVars id = foldr (unionVarSet . ruleRhsFreeVars)
 idUnfoldingVars :: Id -> VarSet
 -- Produce free vars for an unfolding, but NOT for an ordinary
 -- (non-inline) unfolding, since it is a dup of the rhs
+-- and we'll get exponential behaviour if we look at both unf and rhs!
+-- But do look at the *real* unfolding, even for loop breakers, else
+-- we might get out-of-scope variables
 idUnfoldingVars id
-  = case idUnfolding id of
+  = case realIdUnfolding id of
       CoreUnfolding { uf_tmpl = rhs, uf_guidance = InlineRule {} }
 	                   -> exprFreeVars rhs
       DFunUnfolding _ args -> exprsFreeVars args