Sub-issue of #9036: Fix incorrect use of Py_CHARMASK.
diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c
index b182927..81b62e4 100644
--- a/Objects/unicodeobject.c
+++ b/Objects/unicodeobject.c
@@ -8417,7 +8417,7 @@
                 else if (c >= '0' && c <= '9') {
                     prec = c - '0';
                     while (--fmtcnt >= 0) {
-                        c = Py_CHARMASK(*fmt++);
+                        c = *fmt++;
                         if (c < '0' || c > '9')
                             break;
                         if ((prec*10) / 10 != prec) {