[Bug c++/49577] New: [C++0x] narrowing conversion not rejected

[Bug c++/49577] New: [C++0x] narrowing conversion not rejected

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49577

           Summary: [C++0x] narrowing conversion not rejected
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Keywords: accepts-invalid
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: redi@gcc.gnu.org
                CC: jason@gcc.gnu.org


unsigned u{ -1 };
char c = char{ u };

I believe this should be rejected because char{u} is a narrowing conversion and
the FDIS says in [dcl.init.list]/3:

- Otherwise, if the initializer list has a single element, the object or
reference is initialized from that element; if a narrowing conversion (see
below) is required to convert the element to T, the program is ill-formed.


These are correctly rejected:
char c1{ u };
char c2 = { u };
char* p = new char{ u };

[Bug c++/49577] [C++0x] narrowing conversion not rejected

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49577

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> 2011-06-29 12:43:16 UTC ---
... or does this not count as a narrowing conversion because it's not  an
implicit conversion?

[Bug c++/49577] [C++0x] narrowing conversion not rejected

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49577

--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> 2011-06-29 12:49:07 UTC ---
G++ also accepts this, which the example in [dcl.init.list]/7 says is an error:

unsigned int ui1 = {-1}; // error: narrows

[Bug c++/49577] [C++0x] narrowing conversion not rejected

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49577

--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> 2011-06-29 12:54:54 UTC ---
And the following line in the same example:

signed int si1 =
  { (unsigned int)-1 }; // error: narrows

[Bug c++/49577] [C++0x] narrowing conversion not rejected

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49577

Jason Merrill <jason at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2011.08.02 20:00:06
         AssignedTo|unassigned at gcc dot       |jason at gcc dot gnu.org
                   |gnu.org                     |
     Ever Confirmed|0                           |1

[Bug c++/49577] [C++0x] narrowing conversion not rejected

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49577

--- Comment #4 from Jason Merrill <jason at gcc dot gnu.org> 2011-08-02 21:09:20 UTC ---
Author: jason
Date: Tue Aug  2 21:09:17 2011
New Revision: 177215

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=177215
Log:
    PR c++/49577
    * typeck2.c (check_narrowing): Check unsigned mismatch.
    * semantics.c (finish_compound_literal): check_narrowing.

Modified:
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/semantics.c
    trunk/gcc/cp/typeck2.c
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/testsuite/g++.dg/cpp0x/initlist5.C
    trunk/gcc/testsuite/g++.dg/opt/range-test-1.C

[Bug c++/49577] [C++0x] narrowing conversion not rejected

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49577

Jason Merrill <jason at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|---                         |4.7.0

--- Comment #5 from Jason Merrill <jason at gcc dot gnu.org> 2011-08-02 21:33:02 UTC ---
Fixed for 4.7.