--- string.c.old	Tue Aug  3 19:41:41 2010
+++ string.c	Tue Aug  3 19:41:58 2010
@@ -1723,7 +1723,7 @@
 	else if (len <= RSTRING_EMBED_LEN_MAX) {
 	    char *ptr = RSTRING(str)->as.heap.ptr;
 	    STR_SET_EMBED(str);
-	    if (slen > 0) MEMCPY(RSTRING(str)->as.ary, ptr, char, len);
+	    if (len > 0) MEMCPY(RSTRING(str)->as.ary, ptr, char, len);
 	    RSTRING(str)->as.ary[len] = '\0';
 	    STR_SET_EMBED_LEN(str, len);
 	    if (independent) xfree(ptr);