https://git.ruby-lang.org/ruby.git/commit/?id=8f51da5d41

From 8f51da5d41f0642d5a971e4223d1ba14643c6398 Mon Sep 17 00:00:00 2001
From: Nobuyoshi Nakada <nobu@r...>
Date: Fri, 21 Jun 2019 22:42:14 +0900
Subject: Get rid of undefined behavior

* string.c (rb_str_sub_bang): str and repl can be same.
  [Bug #15946]

diff --git a/string.c b/string.c
index 3feeb8c..5a91f6b 100644
--- a/string.c
+++ b/string.c
@@ -5087,7 +5087,7 @@ rb_str_sub_bang(int argc, VALUE *argv, VALUE str) https://github.com/ruby/ruby/blob/trunk/string.c#L5087
 	if (rlen != plen) {
 	    memmove(p + beg0 + rlen, p + beg0 + plen, len - beg0 - plen);
 	}
-	memcpy(p + beg0, rp, rlen);
+	memmove(p + beg0, rp, rlen);
 	len += rlen - plen;
 	STR_SET_LEN(str, len);
 	TERM_FILL(&RSTRING_PTR(str)[len], TERM_LEN(str));
-- 
cgit v0.10.2


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