diff -r 47618b00405b Tools/clinic/clinic.py
--- a/Tools/clinic/clinic.py	Sat Oct 19 10:45:48 2013 +0300
+++ b/Tools/clinic/clinic.py	Sat Oct 19 20:28:11 2013 +0300
@@ -138,12 +138,7 @@
     return s
 
 def rstrip_lines(s):
-    text, add, output = _text_accumulator()
-    for line in s.split('\n'):
-        add(line.rstrip())
-        add('\n')
-    text.pop()
-    return output()
+    return '\n'.join(line.rstrip() for line in s.split('\n'))
 
 def linear_format(s, **kwargs):
     """
@@ -268,11 +263,11 @@
 
 def permute_left_option_groups(l):
     """
-    Given [1, 2, 3], should yield:
+    Given [[1, 2], [3, 4], [5, 6]], should yield:
        ()
-       (3,)
-       (2, 3)
-       (1, 2, 3)
+       (5, 6,)
+       (3, 4, 5, 6)
+       (1, 2, 3, 4, 5, 6)
     """
     yield tuple()
     accumulator = []
@@ -283,11 +278,11 @@
 
 def permute_right_option_groups(l):
     """
-    Given [1, 2, 3], should yield:
+    Given [[1, 2], [3, 4], [5, 6]], should yield:
       ()
-      (1,)
       (1, 2)
-      (1, 2, 3)
+      (1, 2, 3, 4)
+      (1, 2, 3, 4, 5, 6)
     """
     yield tuple()
     accumulator = []
@@ -307,23 +302,19 @@
     If required is empty, left must also be empty.
     """
     required = tuple(required)
-    result = []
 
     if not required:
         assert not left
 
-    accumulator = []
-    counts = set()
+    d = {}
+    plog = tuple(permute_left_option_groups(left))
     for r in permute_right_option_groups(right):
-        for l in permute_left_option_groups(left):
+        for l in plog:
             t = l + required + r
-            if len(t) in counts:
-                continue
-            counts.add(len(t))
-            accumulator.append(t)
-
-    accumulator.sort(key=len)
-    return tuple(accumulator)
+            if len(t) not in d:
+                d[len(t)] = t
+
+    return tuple(sorted(d.values(), key=len))
 
 
 class CLanguage(Language):