B012 Fix false positive with continue/break in loops in finally (#107)

bugbear.py

@@ -285,18 +285,21 @@ def check_for_b011(self, node):
             self.errors.append(B011(node.lineno, node.col_offset))
 
     def check_for_b012(self, node):
-        def _loop(node):
+        def _loop(node, bad_node_types):
             if isinstance(node, (ast.AsyncFunctionDef, ast.FunctionDef)):
                 return
 
-            if isinstance(node, (ast.Return, ast.Continue, ast.Break)):
+            if isinstance(node, (ast.While, ast.For)):
+                bad_node_types = (ast.Return,)
+
+            elif isinstance(node, bad_node_types):
                 self.errors.append(B012(node.lineno, node.col_offset))
 
             for child in ast.iter_child_nodes(node):
-                _loop(child)
+                _loop(child, bad_node_types)
 
         for child in node.finalbody:
-            _loop(child)
+            _loop(child, (ast.Return, ast.Continue, ast.Break))
 
     def walk_function_body(self, node):
         def _loop(parent, node):

tests/b012.py

@@ -82,6 +82,18 @@ def j():
                     continue  # no warning
 
 
+def k():
+    try:
+        pass
+    finally:
+        while True:
+            break  # no warning
+        while True:
+            continue  # no warning
+        while True:
+            return  # warning
+
+
 while True:
     try:
         pass

tests/test_bugbear.py

@@ -132,8 +132,9 @@ def test_b012(self):
             B012(44, 20),
             B012(66, 12),
             B012(78, 12),
-            B012(89, 8),
-            B012(95, 8),
+            B012(94, 12),
+            B012(101, 8),
+            B012(107, 8),
         ]
         self.assertEqual(errors, self.errors(*all_errors))