diff --git a/Modules/_sre.c b/Modules/_sre.c
index f4f9d01dfccf..6518e98f04e4 100644
--- a/Modules/_sre.c
+++ b/Modules/_sre.c
@@ -1002,7 +1002,6 @@ pattern_subx(PatternObject* self, PyObject* ptemplate, PyObject* string,
         int literal;
         view.buf = NULL;
         ptr = getstring(ptemplate, &n, &isbytes, &charsize, &view);
-        b = charsize;
         if (ptr) {
             if (charsize == 1)
                 literal = memchr(ptr, '\\', n) == NULL;