The type checker can't narrow the type of the token value to string,
because it's only loosely correlated with the return token.

We know that a token of '#' should always have a "str" value.
Add an assertion.

Signed-off-by: John Snow <jsnow@redhat.com>
---
 scripts/qapi/parser.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/scripts/qapi/parser.py b/scripts/qapi/parser.py
index d620706fffb..0bc852eda72 100644
--- a/scripts/qapi/parser.py
+++ b/scripts/qapi/parser.py
@@ -304,6 +304,7 @@ def get_doc(self, info):
         cur_doc = QAPIDoc(self, info)
         self.accept(False)
         while self.tok == '#':
+            assert isinstance(self.val, str)
             if self.val.startswith('##'):
                 # End of doc comment
                 if self.val != '##':
-- 
2.30.2