Test that used variable in loop is considered used

Author: ryneeverett

pyflakes/test/test_other.py

@@ -534,6 +534,18 @@ def a():
             b = 2
         ''', m.UnusedVariable)
 
+    def test_variableUsedInLoop(self):
+        """
+        Shadowing a used variable cannot raise an UnusedVariable warning in the
+        context of a loop.
+        """
+        self.flakes('''
+        def a():
+            b = True
+            while b:
+                b = False
+        ''')
+
     def test_assignToGlobal(self):
         """
         Assigning to a global and then not using that global is perfectly