diff --git a/Parser/tokenizer.c b/Parser/tokenizer.c
index 3f6be2f..5ba12a4 100644
--- a/Parser/tokenizer.c
+++ b/Parser/tokenizer.c
@@ -586,7 +586,10 @@
     if (badchar) {
         /* Need to add 1 to the line number, since this line
            has not been counted, yet.  */
-        filename = PyUnicode_DecodeFSDefault(tok->filename);
+        if (tok->filename != NULL)
+            filename = PyUnicode_DecodeFSDefault(tok->filename);
+        else
+            filename = PyUnicode_FromString("<file>");
         if (filename != NULL) {
             PyErr_Format(PyExc_SyntaxError,
                     "Non-UTF-8 code starting with '\\x%.2x' "