c++/10754: cast-as-lvalue extension breaks valid programs

c++/10754: cast-as-lvalue extension breaks valid programs

[jbuck]

>Number:         10754
>Category:       c++
>Synopsis:       cast-as-lvalue extension breaks valid programs
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          wrong-code
>Submitter-Id:   net
>Arrival-Date:   Mon May 12 17:06:00 UTC 2003
>Closed-Date:
>Last-Modified:
>Originator:     Joe Buck
>Release:        3.2.3, 3.3-pre, 3.4-pre
>Organization:
>Environment:

>Description:
The cast-as-lvalue extension causes g++ to incorrectly resolve
overloaded functions when the argument is a cast.  For example, compile and run the following program:

----------------
#include <iostream>

void foo(int&) {
    std::cout << "foo(int&) called\n";
}

void foo(const int&) {
    std::cout << "foo(const int&) called\n";
}

int main(int, char**) {
    unsigned u = 0;
    foo((int)u);
}
>How-To-Repeat:
Compile the above program, run it, and you'll get the message

foo(int&) called

instead of the correct answer,

foo(const int&) called.

This is broken at least as far back as 2.95.2, however,
2.7.2.1 handles it correctly (if iostream.h is used and
the std:: references are dropped).
>Fix:

>Release-Note:
>Audit-Trail:
>Unformatted: