[Bug c++/81597] New: returns link to temporary value

["lisp2d at rambler dot ru" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81597

            Bug ID: 81597
           Summary: returns link to temporary value
           Product: gcc
           Version: 4.8.5
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: lisp2d at rambler dot ru
  Target Milestone: ---

Functions returning C && , C const && , C const & from temporary object will
ALWAYS with wrong result.
Warning is good but ...
To do : prevent return rvalue from those functions.

example :

//> g++ -std=c++11 returntemp.cpp -o returntemp
#include  <iostream>

int && f  ( ) {
  return  1 ; }

int && g  ( ) {
  return  2 ; }

int const &&  ft  ( ) {
  return  7 ; }

int const &&  gt  ( ) {
  return  8 ; }  

int const & fc  ( ) {
  return  5 ; }

int const & gc  ( ) {
  return  6 ; }

int fok ( ) {
  return  3 ; }

int gok ( ) {
  return  4 ; }  

int main  ( int , char  * * ) {
  std ::  cout  <<  "int &&"  <<  std ::  endl  ;
  { int &&  x ( f ( ) ) ;
    std ::  cout  <<  "x="  <<  x <<  std ::  endl  ;
    int &&  y ( g ( ) ) ;
    std ::  cout  <<  "y="  <<  y <<  std ::  endl  ;
    std ::  cout  <<  "x="  <<  x <<  std ::  endl  ; }
  std ::  cout  <<  "---"  <<  std ::  endl  ;
  std ::  cout  <<  "int const &&"  <<  std ::  endl  ;
  { int const &&  x ( ft  ( ) ) ;
    std ::  cout  <<  "x="  <<  x <<  std ::  endl  ;
    int const &&  y ( gt  ( ) ) ;
    std ::  cout  <<  "y="  <<  y <<  std ::  endl  ;
    std ::  cout  <<  "x="  <<  x <<  std ::  endl  ; }
  std ::  cout  <<  "---"  <<  std ::  endl  ;
  std ::  cout  <<  "int const &"  <<  std ::  endl  ;
  { int const & x ( fc  ( ) ) ;
    std ::  cout  <<  "x="  <<  x <<  std ::  endl  ;
    int const & y ( gc  ( ) ) ;
    std ::  cout  <<  "y="  <<  y <<  std ::  endl  ;
    std ::  cout  <<  "x="  <<  x <<  std ::  endl  ; }
  std ::  cout  <<  "---"  <<  std ::  endl  ;
  std ::  cout  <<  "int"  <<  std ::  endl  ;
  { int &&  x ( fok ( ) ) ;
    std ::  cout  <<  "x="  <<  x <<  std ::  endl  ;
    int &&  y ( gok ( ) ) ;
    std ::  cout  <<  "y="  <<  y <<  std ::  endl  ;
    std ::  cout  <<  "x="  <<  x <<  std ::  endl  ; } }

result :

int &&
x=1
y=2
x=32621
---
int const &&
x=7
y=8
x=32621
---
int const &
x=5
y=6
x=32621
---
int
x=3
y=4
x=3