iter_yield_expr should not work correctly.

parso/python/tree.py

@@ -108,7 +108,7 @@ class PythonLeaf(PythonMixin, Leaf):
         #   indent error leafs somehow? No idea how, though.
         previous_leaf = self.get_previous_leaf()
         if previous_leaf is not None and previous_leaf.type == 'error_leaf' \
-                and previous_leaf.original_type == 'error_dedent':
+                and previous_leaf.original_type in ('indent', 'error_dedent'):
             previous_leaf = previous_leaf.get_previous_leaf()
 
         if previous_leaf is None:

test/test_parser_tree.py

@@ -121,13 +121,21 @@ def get_yield_exprs(code, version):
     return list(parse(code, version=version).children[0].iter_yield_exprs())
 
 
+def get_return_stmts(code):
+    return list(parse(code).children[0].iter_return_stmts())
+
+
 def test_yields(each_version):
     y, = get_yield_exprs('def x(): yield', each_version)
     assert y.value == 'yield'
+    assert y.type == 'keyword'
 
     y, = get_yield_exprs('def x(): (yield 1)', each_version)
     assert y.type == 'yield_expr'
 
+    y, = get_yield_exprs('def x(): [1, (yield)]', each_version)
+    assert y.type == 'keyword'
+
 
 def test_yield_from():
     y, = get_yield_exprs('def x(): (yield from 1)', '3.3')