Silence a warning under clang/asan

This should silence the following warning:

dump.c:459:57: warning: comparison of constant 85 with expression of
   type 'svtype' is always false [-Wtautological-constant-out-of-range-compare]

The warning is a false positive, this code is /meant/ to detect
conditions that should not happen.

1 files changed, 2 insertions, 1 deletions

diff --git a/dump.c b/dump.c
index c802732c7d..fcc63fcd8f 100644
--- a/dump.c
+++ b/dump.c
@@ -456,7 +456,8 @@ Perl_sv_peek(pTHX_ SV *sv)
 	sv_catpv(t, "VOID");
 	goto finish;
     }
-    else if (sv == (const SV *)0x55555555 || SvTYPE(sv) == 'U') {
+    else if (sv == (const SV *)0x55555555 || ((char)SvTYPE(sv)) == 'U') {
+        /* detect data corruption under memory poisoning */
 	sv_catpv(t, "WILD");
 	goto finish;
     }