Add and fix some async/await issues.

parso/python/normalizer.py

@@ -3,6 +3,7 @@ from contextlib import contextmanager
 from parso.normalizer import Normalizer, NormalizerConfig, Issue
 
 _BLOCK_STMTS = ('if_stmt', 'while_stmt', 'for_stmt', 'try_stmt', 'with_stmt')
+_ASYNC_FUNC_TYPES = 'async_funcdef', 'async_stmt'
 # This is the maximal block size given by python.
 _MAX_BLOCK_SIZE = 20
 
@@ -22,6 +23,7 @@ class Context(object):
     def __init__(self, node, parent_context=None):
         self.node = node
         self.blocks = []
+        self.parent_context = parent_context
 
     @contextmanager
     def add_block(self, node):
@@ -130,8 +132,13 @@ class ErrorFinder(Normalizer):
                 self._add_syntax_error("'%s' outside function" % leaf.value, leaf)
         elif leaf.value == 'await':
             if self._context.node.type != 'funcdef' \
-                    or self._context.node.parent.type != 'async_funcdef':
+                    or self._context.node.parent.type not in _ASYNC_FUNC_TYPES:
                 self._add_syntax_error("'await' outside async function", leaf)
+        elif leaf.value == 'from' and leaf.parent.type == 'yield_arg' \
+                and self._context.node.type == 'funcdef' \
+                and self._context.node.parent.type in _ASYNC_FUNC_TYPES:
+            yield_ = leaf.parent.parent
+            self._add_syntax_error("'yield from' inside async function", yield_)
         return ''
 
     def _add_indentation_error(self, message, spacing):

test/normalizer_issue_files/allowed_syntax_python3.5.py

@@ -0,0 +1,19 @@
+"""
+Mostly allowed syntax in Python 3.5.
+"""
+
+
+async def foo():
+    yield 1
+    await bar()
+    #: E901
+    yield from []
+
+
+# With decorator it's a different statement.
+@bla
+async def foo():
+    yield 1
+    await bar()
+    #: E901
+    yield from []

test/test_python_errors.py

@@ -59,8 +59,9 @@ def test_indentation_errors(code, positions):
 @pytest.mark.parametrize(
     'code', [
         # SyntaxError
-        pytest.mark.skipif('sys.version_info < (2, 6)', '1 +'),
-        pytest.mark.skipif('sys.version_info < (2, 6)', '?'),
+        # Python 2.6 has a bit different error messages here, so skip it.
+        pytest.mark.skipif('sys.version_info <= (2, 6)', '1 +'),
+        pytest.mark.skipif('sys.version_info <= (2, 6)', '?'),
         dedent('''\
             for a in [1]:
                 try:
@@ -97,6 +98,7 @@ def test_python_exception_matches(code):
         # SyntaxError
         ('async def bla():\n def x():  await bla()', '3.5'),
         ('yield from []', '3.5'),
+        ('async def foo(): yield from []', '3.5'),
     ]
 )
 def test_python_exception_matches_version(code, version):