From: Christian Bauer <Christian.Bauer@uni-mainz.de>
Date: Fri, 20 Aug 2004 20:13:09 +0000 (+0000)
Subject: cache other.p in assignment; this should fix the "assignment of
X-Git-Tag: release_1-3-0~31
X-Git-Url: https://www.ginac.de/ginac.git//ginac.git?p=ginac.git;a=commitdiff_plain;h=dffb4439ad438c76002d6b7798e5e3b651a2ac19

cache other.p in assignment; this should fix the "assignment of
sub-expression" problem with operator[]
---

diff --git a/ginac/ptr.h b/ginac/ptr.h
index 7f305fe1..4c4ea71d 100644
--- a/ginac/ptr.h
+++ b/ginac/ptr.h
@@ -80,11 +80,14 @@ public:
 
 	ptr &operator=(const ptr & other)
 	{
-		// NB: must first add reference to "other", since other might be *this.
-		other.p->add_reference();
+		// NB1: Must first add reference to "other", since other might be *this.
+		// NB2: Cache other.p, because if "other" is a subexpression of p,
+		//      deleting p will also invalidate "other".
+		T *otherp = other.p;
+		otherp->add_reference();
 		if (p->remove_reference() == 0)
 			delete p;
-		p = other.p;
+		p = otherp;
 		return *this;
 	}