enable support for yield in return expressions

--HG--
extra : transplant_source : %94%87%D7e%B9%82%EF%926%26o%C0%8E%0DcY%C3%E3n%DB

Cython/Compiler/ParseTreeTransforms.py

@@ -2096,13 +2096,14 @@ class YieldNodeCollector(TreeVisitor):
         self.has_return_value = False
 
     def visit_Node(self, node):
-        return self.visitchildren(node)
+        self.visitchildren(node)
 
     def visit_YieldExprNode(self, node):
         self.yields.append(node)
         self.visitchildren(node)
 
     def visit_ReturnStatNode(self, node):
+        self.visitchildren(node)
         if node.value:
             self.has_return_value = True
         self.returns.append(node)
@@ -2119,6 +2120,7 @@ class YieldNodeCollector(TreeVisitor):
     def visit_GeneratorExpressionNode(self, node):
         pass
 
+
 class MarkClosureVisitor(CythonTransform):
 
     def visit_ModuleNode(self, node):

tests/run/yield_from_pep380.pyx

@@ -1004,3 +1004,17 @@ def test_delegating_generators_claim_to_be_running_close():
     ret = next(g1)
     g1.close()
     return ret
+
+
+def yield_in_return(x):
+    """
+    >>> x = yield_in_return(range(3))
+    >>> while True:
+    ...     try:
+    ...         print(next(x))
+    ...     except StopIteration as exc:
+    ...         print(exc.value)
+    ...     break
+
+    """
+    return (yield from x)