1 files changed, 2 insertions, 2 deletions
diff --git a/proto.h b/proto.h
index ea56c4d604..2de342bc85 100644
--- a/proto.h
+++ b/proto.h
@@ -5095,10 +5095,10 @@ Perl_utf16_to_utf8_reversed(pTHX_ U8 *p, U8 *d, Size_t bytelen, Size_t *newlen);
         assert(p); assert(d); assert(newlen)
 
 PERL_CALLCONV STRLEN
-Perl_utf8_length(pTHX_ const U8 *s, const U8 *e)
+Perl_utf8_length(pTHX_ const U8 *s0, const U8 *e)
         __attribute__warn_unused_result__;
 #define PERL_ARGS_ASSERT_UTF8_LENGTH            \
-        assert(s); assert(e)
+        assert(s0); assert(e)
 
 PERL_CALLCONV U8 *
 Perl_utf8_to_bytes(pTHX_ U8 *s, STRLEN *lenp);