diff --git a/ChangeLog b/ChangeLog
index 0e43e1df72..f093b8412d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Tue May  6 23:28:47 2014  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* parse.y (local_tbl_gen): remove local variables duplicated with
+	  arguments.
+
 Tue May  6 18:48:50 2014  Tanaka Akira  <akr@fsij.org>
 
 	* lib/time.rb (Time.make_time): Adjust the time zone of "now".
diff --git a/parse.y b/parse.y
index 8fcbe3a2c0..888b12c75e 100644
--- a/parse.y
+++ b/parse.y
@@ -9714,31 +9714,26 @@ local_pop_gen(struct parser_params *parser)
 }
 
 #ifndef RIPPER
-static ID*
-vtable_tblcpy(ID *buf, const struct vtable *src)
-{
-    int i, cnt = vtable_size(src);
-
-    if (cnt > 0) {
-        buf[0] = cnt;
-        for (i = 0; i < cnt; i++) {
-            buf[i] = src->tbl[i];
-        }
-        return buf;
-    }
-    return 0;
-}
-
 static ID*
 local_tbl_gen(struct parser_params *parser)
 {
-    int cnt = vtable_size(lvtbl->args) + vtable_size(lvtbl->vars);
+    int cnt_args = vtable_size(lvtbl->args);
+    int cnt_vars = vtable_size(lvtbl->vars);
+    int cnt = cnt_args + cnt_vars;
+    int i, j;
     ID *buf;
 
     if (cnt <= 0) return 0;
     buf = ALLOC_N(ID, cnt + 1);
-    vtable_tblcpy(buf+1, lvtbl->args);
-    vtable_tblcpy(buf+vtable_size(lvtbl->args)+1, lvtbl->vars);
+    MEMCPY(buf+1, lvtbl->args->tbl, ID, cnt_args);
+    /* remove IDs duplicated to warn shadowing */
+    for (i = 0, j = cnt_args+1; i < cnt_vars; ++i) {
+	ID id = lvtbl->vars->tbl[i];
+	if (!vtable_included(lvtbl->args, id)) {
+	    buf[j++] = id;
+	}
+    }
+    if (--j < cnt) REALLOC_N(buf, ID, (cnt = j) + 1);
     buf[0] = cnt;
     return buf;
 }
diff --git a/test/ruby/test_variable.rb b/test/ruby/test_variable.rb
index ab4d44938a..89f1d58348 100644
--- a/test/ruby/test_variable.rb
+++ b/test/ruby/test_variable.rb
@@ -83,6 +83,12 @@ class TestVariable < Test::Unit::TestCase
     end.call
   end
 
+  def test_shadowing_local_variables
+    bug9486 = '[ruby-core:60501] [Bug #9486]'
+    x = tap {|x| break local_variables}
+    assert_equal([:x, :bug9486, :x], x)
+  end
+
   def local_variables_of(bind)
     this_should_not_be_in_bind = 2
     bind.local_variables