Merge pull request #11382 from felixzhuologist/master

Fix  #11312: nonlocal does not raise SyntaxError

IPython/core/async_helpers.py

@@ -97,14 +97,22 b' class _AsyncSyntaxErrorVisitor(ast.NodeVisitor):'
     the implementation involves wrapping the repl in an async function, it
     is erroneously allowed (e.g. yield or return at the top level)
     """
+    def __init__(self):
+        self.depth = 0
+        super().__init__()
 
     def generic_visit(self, node):
         func_types = (ast.FunctionDef, ast.AsyncFunctionDef)
-        invalid_types = (ast.Return, ast.Yield, ast.YieldFrom)
-
-        if isinstance(node, func_types):
-            return  # Don't recurse into functions
-        elif isinstance(node, invalid_types):
+        invalid_types_by_depth = {
+            0: (ast.Return, ast.Yield, ast.YieldFrom),
+            1: (ast.Nonlocal,)
+        }
+
+        should_traverse = self.depth < max(invalid_types_by_depth.keys())
+        if isinstance(node, func_types) and should_traverse:
+            self.depth += 1
+            super().generic_visit(node)
+        elif isinstance(node, invalid_types_by_depth[self.depth]):
             raise SyntaxError()
         else:
             super().generic_visit(node)

IPython/core/tests/test_async_helpers.py

@@ -227,6 +227,35 b' if sys.version_info > (3, 5):'
                             else:
                                 iprc(cell)
 
+        def test_nonlocal(self):
+            # fails if outer scope is not a function scope or if var not defined
+            with self.assertRaises(SyntaxError):
+                iprc("nonlocal x")
+                iprc("""
+                x = 1
+                def f():
+                    nonlocal x
+                    x = 10000
+                    yield x
+                """)
+                iprc("""
+                def f():
+                    def g():
+                        nonlocal x
+                        x = 10000
+                        yield x
+                """)
+
+            # works if outer scope is a function scope and var exists
+            iprc("""
+            def f():
+                x = 20
+                def g():
+                    nonlocal x
+                    x = 10000
+                    yield x
+            """)
+
 
         def test_execute(self):
             iprc("""