Re: c++/6507: auto type promotion of referee in reference member variable initialization

[Hill Stephen-STEHILL1 <Stephen dot Hill at motorola dot com>]

The following reply was made to PR c++/6507; it has been noted by GNATS.

From: Hill Stephen-STEHILL1 <Stephen.Hill@motorola.com>
To: Hill Stephen-STEHILL1 <Stephen.Hill@motorola.com>,
   "'gcc-gnats@gcc.gnu.org'" <gcc-gnats@gcc.gnu.org>,
   "'gcc-prs@gcc.gnu.org'" <gcc-prs@gcc.gnu.org>,
   "'gcc-bugs@gcc.gnu.org'"
	 <gcc-bugs@gcc.gnu.org>,
   "'nobody@gcc.gnu.org'" <nobody@gcc.gnu.org>
Cc:  
Subject: Re: c++/6507: auto type promotion of referee in reference member 
	variable initialization
Date: Fri, 17 Jan 2003 14:41:56 -0000

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 Apologies,
 I had some email issues which led to my mail of the testcase (attached)
 being bounced. This got missed in the email deluge on my return from a
 holiday. So here is the testcase again.
 
 Thanks
 
 Steve 
 
 
  <<bug_test.cc>>
 http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&p
 r=6507
 
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 /*	gcc version 3.1  configured with configure  --enable-threads =
 --with-cpu=3Di686
 	first discovered on g++ version 2.95.2 19991024 (release)=20
 =09
 	bug_test - steve hill 29/04/02.  email: stephen.hill@motorola.com
 =09
 	a,b are constant references to private member variables p_a,p_b. If we =
 get the class wrong on p_b (line 52), then b and p_b are of different =
 classes
 	but the compiler does not issue a warning or error, and makes p_b =
 refer to a different address than the one we intend - probably because =
 the automatic=20
 	type promotion is invoked. No warning is issued that auto type =
 promotion (or whatever) has changed the address of the referee. */
 #include <iostream>
 using namespace std;
 
 typedef unsigned short int ID;
 
 class Foo
 {
 	int i;
 =09
 	public:
 		Foo(int j) 			//no bug if this is declared as explicit
 			:i(j)
 		{};
 	=09
 /*	 //Issues a compile error if this is included because auto type =
 promotion is not now possible
 		Foo()
 			:i(0)
 		{};=20
 */
 		~Foo()
 		{};
 };
 
 
 class bug_test
 {
 	public:
 		const ID &a;
 		const Foo &b; =20
 =09
 		bug_test()
 			:a(p_a),b(p_b),p_a(1),p_b(2)
 		{
 			cerr<<"Reference addresses:\t" << &a << " " << &b  << "\n";
 			cerr<<"Referee addresses:\t"<<&p_a << " " << &p_b  << "\n";
 		};
 
 		~bug_test()
 		{};
 =09
 	private:
 		ID p_a;
 		ID p_b;		// !! should be declared as a Foo !! 			=09
 };
 
 int main()
 {
 	bug_test b;
 	return 0;
 }
 
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