[3.7] bpo-33363: raise SyntaxError for async for/with outside async functions (GH-6616). (GH-6619)

Author: zsol

Lib/test/test_coroutines.py

@@ -362,7 +362,22 @@ async def bar(): pass
  """def foo():
  async def bar():
  pass\nawait a
- """]
+ """,
+ """def foo():
+ async for i in arange(2):
+ pass
+ """,
+ """def foo():
+ async with resource:
+ pass
+ """,
+ """async with resource:
+ pass
+ """,
+ """async for i in arange(2):
+ pass
+ """,
+ ]
 
  for code in samples:
  with self.subTest(code=code), self.assertRaises(SyntaxError):

Misc/NEWS.d/next/Core and Builtins/2018-04-26-22-48-28.bpo-33363.8RCnN2.rst

@@ -0,0 +1,2 @@
+Raise a SyntaxError for ``async with`` and ``async for`` statements outside
+of async functions.

Python/compile.c

@@ -2339,6 +2339,10 @@ compiler_async_for(struct compiler *c, stmt_ty s)
  basicblock *try, *except, *end, *after_try, *try_cleanup,
  *after_loop_else;
 
+ if (c->u->u_scope_type != COMPILER_SCOPE_ASYNC_FUNCTION) {
+ return compiler_error(c, "'async for' outside async function");
+ }
+
  PyObject *stop_aiter_error = _PyUnicode_FromId(&PyId_StopAsyncIteration);
  if (stop_aiter_error == NULL) {
  return 0;
@@ -4204,6 +4208,9 @@ compiler_async_with(struct compiler *c, stmt_ty s, int pos)
  withitem_ty item = asdl_seq_GET(s->v.AsyncWith.items, pos);
 
  assert(s->kind == AsyncWith_kind);
+ if (c->u->u_scope_type != COMPILER_SCOPE_ASYNC_FUNCTION) {
+ return compiler_error(c, "'async with' outside async function");
+ }
 
  block = compiler_new_block(c);
  finally = compiler_new_block(c);