[Bug c++/26671] New: Missing "warning: reference to local variable returned"

[Bug c++/26671] New: Missing "warning: reference to local variable returned"

[carolh at sinavigator dot com]

class test
{
public:
  int secondMember;
};
class test2
{
public:
  int requiredForTest;
  int secondMember;

};
int &
returnRefToLocalOK()
{
  test local;

  return local.secondMember;
}
int &
returnRefToLocalMissing()
{
  test2 local;

  return local.secondMember;
}
int
main()
{
  return returnRefToLocalOK();
  return returnRefToLocalMissing();
}

===========
gcc fails to generate the warning "reference to local variable returned" for
function returnRefToLocalMissing().


Reading specs from /usr/local/lib/gcc-lib/i686-pc-linux-gnu/3.3.6/specs
Configured with: ../configure 
Thread model: posix
gcc version 3.3.6

the command line and resulting output:
gcc test.cc
test.cc: In function `int& returnRefToLocalOK()':
test.cc:16: warning: reference to local variable `local' returned

the preprocessed file:
# 1 "test.cc"
# 1 "<built-in>"
# 1 "<command line>"
# 1 "test.cc"
class test
{
public:
  int secondMember;
};
class test2
{
public:
  int requiredForTest;
  int secondMember;

};
int &
returnRefToLocalOK()
{
  test local;

  return local.secondMember;
}
int &
returnRefToLocalMissing()
{
  test2 local;

  return local.secondMember;
}
int
main()
{
  return returnRefToLocalOK();
  return returnRefToLocalMissing();
}

Also  occurs in gcc versions 3.3.3 through 3.3.5.


-- 
           Summary: Missing "warning: reference to local variable returned"
           Product: gcc
           Version: 3.3.6
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: carolh at sinavigator dot com
  GCC host triplet: i686-pc-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26671

[Bug c++/26671] [4.0/4.1/4.2 Regression] Missing "warning: reference to local variable returned"

[pinskia at gcc dot gnu dot org]

------- Comment #1 from pinskia at gcc dot gnu dot org  2006-03-14 00:10 -------
It is even worse in 4.0.0 and above where we don't warn at all, I will look
into this later this week.

I am going to mark this as a regression for 4.0 because I think my fix will
also fix both reference to local variable problem.

Oh and the C front-end is not affected.

Related to the old PR 14156.


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |pinskia at gcc dot gnu dot
                   |                            |org
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
           Keywords|                            |diagnostic
      Known to fail|                            |4.0.0 4.1.0 4.2.0
   Last reconfirmed|0000-00-00 00:00:00         |2006-03-14 00:10:44
               date|                            |
            Summary|Missing "warning: reference |[4.0/4.1/4.2 Regression]
                   |to local variable returned" |Missing "warning: reference
                   |                            |to local variable returned"
   Target Milestone|---                         |4.0.4


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26671

[Bug c++/26671] [4.0/4.1/4.2 Regression] Missing "warning: reference to local variable returned"

[mmitchel at gcc dot gnu dot org]

-- 

mmitchel at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P2


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26671

[Bug c++/26671] [4.0/4.1/4.2 Regression] Missing "warning: reference to local variable returned"

[pluto at agmk dot net]

------- Comment #2 from pluto at agmk dot net  2006-06-28 08:56 -------
following testcase doesn't generate warning in 4.1.2svn.
3.3.6 works fine.

#include <string>
std::string const& foo()
{
        std::string tab[ 1 ] = { std::string( "text" ) };
        int const idx = 0;
        return tab[ idx ];
}


-- 

pluto at agmk dot net changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |pluto at agmk dot net


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26671

[Bug c++/26671] [4.0/4.1/4.2 Regression] Missing "warning: reference to local variable returned"

[jason at gcc dot gnu dot org]

------- Comment #3 from jason at gcc dot gnu dot org  2006-07-05 18:19 -------
added known to work in 3.3.6


-- 

jason at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to work|                            |3.3.6


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26671

[Bug c++/26671] [4.0/4.1/4.2 Regression] Missing "warning: reference to local variable returned"

[jason at gcc dot gnu dot org]

-- 

jason at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |jason at gcc dot gnu dot org
                   |dot org                     |
             Status|NEW                         |ASSIGNED
   Last reconfirmed|2006-03-14 00:10:44         |2006-09-06 00:23:58
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26671

[Bug c++/26671] [4.0/4.1/4.2 Regression] Missing "warning: reference to local variable returned"

[jason at gcc dot gnu dot org]

------- Comment #4 from jason at gcc dot gnu dot org  2006-09-06 05:25 -------
Subject: Bug 26671

Author: jason
Date: Wed Sep  6 05:25:29 2006
New Revision: 116714

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=116714
Log:
        PR c++/26671
        * typeck.c (maybe_warn_about_returning_address_of_local): Look
        through COMPONENT_REF and ARRAY_REF.

Added:
    trunk/gcc/testsuite/g++.dg/warn/return-reference2.C
Modified:
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/typeck.c


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26671

[Bug c++/26671] [4.0/4.1 Regression] Missing "warning: reference to local variable returned"

[jason at gcc dot gnu dot org]

------- Comment #5 from jason at gcc dot gnu dot org  2006-09-07 22:27 -------
Subject: Bug 26671

Author: jason
Date: Thu Sep  7 22:27:01 2006
New Revision: 116763

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=116763
Log:
        PR c++/26195
        * decl.c (make_rtl_for_nonlocal_decl),
        (start_preparsed_function): Don't use lbasename on
        input_filename when calling get_fileinfo.
        * semantics.c (begin_class_definition): Likewise.
        * lex.c (cxx_make_type): Likewise.
        (handle_pragma_interface): Call get_fileinfo on input_filename,
        not on the parameter to the directive.

        PR c++/26696
        * cvt.c (convert_to_void): Replace a subexpression with no side
        effects with void_zero_node.
        * tree.c (is_overloaded_fn): Look through COMPONENT_REF.
        (get_first_fn): Ditto.
        * decl.c (grokdeclarator): No need to look through COMPONENT_REF.

        PR c++/26571
        * parser.c (cp_parser_diagnose_invalid_type_name): Handle the case
        where the name is a type used incorrectly.

        PR c++/26671
        * typeck.c (maybe_warn_about_returning_address_of_local): Look
        through COMPONENT_REF and ARRAY_REF.

        PR c++/26102
        * name-lookup.c (do_class_using_decl): Try to find the base even
        if bases_dependent_p.
        * pt.c (type_dependent_expression_p): A USING_DECL is dependent.

        PR c++/19809
        * pt.c (tsubst_friend_function): Set DECL_INITIAL before pushdecl.

Modified:
    branches/gcc-4_1-branch/gcc/cp/ChangeLog
    branches/gcc-4_1-branch/gcc/cp/cvt.c
    branches/gcc-4_1-branch/gcc/cp/decl.c
    branches/gcc-4_1-branch/gcc/cp/lex.c
    branches/gcc-4_1-branch/gcc/cp/name-lookup.c
    branches/gcc-4_1-branch/gcc/cp/parser.c
    branches/gcc-4_1-branch/gcc/cp/pt.c
    branches/gcc-4_1-branch/gcc/cp/semantics.c
    branches/gcc-4_1-branch/gcc/cp/tree.c
    branches/gcc-4_1-branch/gcc/cp/typeck.c


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26671

[Bug c++/26671] [4.0/4.1 Regression] Missing "warning: reference to local variable returned"

[jason at gcc dot gnu dot org]

------- Comment #6 from jason at gcc dot gnu dot org  2006-09-07 22:38 -------
Subject: Bug 26671

Author: jason
Date: Thu Sep  7 22:38:03 2006
New Revision: 116764

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=116764
Log:
        PR c++/26195
        * decl.c (make_rtl_for_nonlocal_decl),
        (start_preparsed_function): Don't use lbasename on
        input_filename when calling get_fileinfo.
        * semantics.c (begin_class_definition): Likewise.
        * lex.c (cxx_make_type): Likewise.
        (handle_pragma_interface): Call get_fileinfo on input_filename,
        not on the parameter to the directive.

        PR c++/26696
        * cvt.c (convert_to_void): Replace a subexpression with no side
        effects with void_zero_node.
        * tree.c (is_overloaded_fn): Look through COMPONENT_REF.
        (get_first_fn): Ditto.
        * decl.c (grokdeclarator): No need to look through COMPONENT_REF.

        PR c++/26571
        * parser.c (cp_parser_diagnose_invalid_type_name): Handle the case
        where the name is a type used incorrectly.

        PR c++/26671
        * typeck.c (maybe_warn_about_returning_address_of_local): Look
        through COMPONENT_REF and ARRAY_REF.

        PR c++/19809
        * pt.c (tsubst_friend_function): Set DECL_INITIAL before pushdecl.

Modified:
    branches/gcc-4_0-branch/gcc/cp/ChangeLog
    branches/gcc-4_0-branch/gcc/cp/cvt.c
    branches/gcc-4_0-branch/gcc/cp/decl.c
    branches/gcc-4_0-branch/gcc/cp/lex.c
    branches/gcc-4_0-branch/gcc/cp/parser.c
    branches/gcc-4_0-branch/gcc/cp/pt.c
    branches/gcc-4_0-branch/gcc/cp/semantics.c
    branches/gcc-4_0-branch/gcc/cp/tree.c
    branches/gcc-4_0-branch/gcc/cp/typeck.c


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26671

[Bug c++/26671] [4.0/4.1 Regression] Missing "warning: reference to local variable returned"

[jason at gcc dot gnu dot org]

------- Comment #7 from jason at gcc dot gnu dot org  2006-09-07 23:05 -------
Fixed


-- 

jason at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26671