[Bug c++/48728] New: cannot construct a vector of unique_ptr from an initializer list

[Bug c++/48728] New: cannot construct a vector of unique_ptr from an initializer list

[john.salmon at deshaw dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48728

           Summary: cannot construct a vector of unique_ptr from an
                    initializer list
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: john.salmon@deshaw.com


I think the problem here is that the vector constructor is trying to invoke a
copy-constructor to create the elements of the vector from the elements of the
initializer list.  But there is no copy-constructor for a unique_ptr. 
According to Table 97 of the FCD, the elements, T, need only be
MoveConstructible, not CopyConstructible, so I think the library is wrong to
invoke the copy constructor.

salmonj@drdlogin0039.en.desres$ cat v.cpp
#include <memory>
#include <vector>

struct Foo{
    int i;
};
typedef std::unique_ptr<Foo> up;

std::vector<up> bad{up{new Foo}, up{new Foo}};



salmonj@drdlogin0039.en.desres$ desres-cleanenv -m gcc/4.6.0-23A/bin g++ -v
-save-temps -std=c++0x -Wall -c -o v.o v.cpp
Reading specs from
/proj/desrad-c/root/Linux/x86_64/gcc/4.6.0-23A/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.6.0/specs
COLLECT_GCC=g++
COLLECT_LTO_WRAPPER=/proj/desrad-c/root/Linux/x86_64/gcc/4.6.0-23A/bin/../libexec/gcc/x86_64-unknown-linux-gnu/4.6.0/lto-wrapper
Target: x86_64-unknown-linux-gnu
Configured with:
/state/partition1/tmp/desres-install.158e2ef1dc69/gcc-4.6.0-23A/gcc-4.6.0/configure
--prefix=/proj/desres/root/Linux/x86_64/gcc/4.6.0-23A
--with-local-prefix=/proj/desres/root/Linux/x86_64/gcc/4.6.0-23A/local
--enable-languages=c,c++,fortran,java
Thread model: posix
gcc version 4.6.0 (GCC) 
COLLECT_GCC_OPTIONS='-v' '-save-temps' '-std=c++0x' '-Wall' '-c' '-o' 'v.o'
'-shared-libgcc' '-mtune=generic' '-march=x86-64'

/proj/desrad-c/root/Linux/x86_64/gcc/4.6.0-23A/bin/../libexec/gcc/x86_64-unknown-linux-gnu/4.6.0/cc1plus
-E -quiet -v -iprefix
/proj/desrad-c/root/Linux/x86_64/gcc/4.6.0-23A/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.6.0/
-D_GNU_SOURCE v.cpp -mtune=generic -march=x86-64 -std=c++0x -Wall
-fpch-preprocess -o v.ii
ignoring nonexistent directory
"/proj/desrad-c/root/Linux/x86_64/gcc/4.6.0-23A/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.6.0/../../../../x86_64-unknown-linux-gnu/include"
ignoring duplicate directory
"/proj/desrad-c/root/Linux/x86_64/gcc/4.6.0-23A/bin/../lib/gcc/../../lib/gcc/x86_64-unknown-linux-gnu/4.6.0/../../../../include/c++/4.6.0"
ignoring duplicate directory
"/proj/desrad-c/root/Linux/x86_64/gcc/4.6.0-23A/bin/../lib/gcc/../../lib/gcc/x86_64-unknown-linux-gnu/4.6.0/../../../../include/c++/4.6.0/x86_64-unknown-linux-gnu"
ignoring duplicate directory
"/proj/desrad-c/root/Linux/x86_64/gcc/4.6.0-23A/bin/../lib/gcc/../../lib/gcc/x86_64-unknown-linux-gnu/4.6.0/../../../../include/c++/4.6.0/backward"
ignoring duplicate directory
"/proj/desrad-c/root/Linux/x86_64/gcc/4.6.0-23A/bin/../lib/gcc/../../lib/gcc/x86_64-unknown-linux-gnu/4.6.0/include"
ignoring nonexistent directory
"/proj/desres/root/Linux/x86_64/gcc/4.6.0-23A/local/include"
ignoring duplicate directory
"/proj/desrad-c/root/Linux/x86_64/gcc/4.6.0-23A/bin/../lib/gcc/../../lib/gcc/x86_64-unknown-linux-gnu/4.6.0/include-fixed"
ignoring nonexistent directory
"/proj/desrad-c/root/Linux/x86_64/gcc/4.6.0-23A/bin/../lib/gcc/../../lib/gcc/x86_64-unknown-linux-gnu/4.6.0/../../../../x86_64-unknown-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:

/proj/desrad-c/root/Linux/x86_64/gcc/4.6.0-23A/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.6.0/../../../../include/c++/4.6.0

/proj/desrad-c/root/Linux/x86_64/gcc/4.6.0-23A/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.6.0/../../../../include/c++/4.6.0/x86_64-unknown-linux-gnu

/proj/desrad-c/root/Linux/x86_64/gcc/4.6.0-23A/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.6.0/../../../../include/c++/4.6.0/backward

/proj/desrad-c/root/Linux/x86_64/gcc/4.6.0-23A/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.6.0/include

/proj/desrad-c/root/Linux/x86_64/gcc/4.6.0-23A/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.6.0/include-fixed
 /proj/desrad-c/root/Linux/x86_64/gcc/4.6.0-23A/bin/../lib/gcc/../../include
 /usr/include
End of search list.
COLLECT_GCC_OPTIONS='-v' '-save-temps' '-std=c++0x' '-Wall' '-c' '-o' 'v.o'
'-shared-libgcc' '-mtune=generic' '-march=x86-64'

/proj/desrad-c/root/Linux/x86_64/gcc/4.6.0-23A/bin/../libexec/gcc/x86_64-unknown-linux-gnu/4.6.0/cc1plus
-fpreprocessed v.ii -quiet -dumpbase v.cpp -mtune=generic -march=x86-64
-auxbase-strip v.o -Wall -std=c++0x -version -o v.s
GNU C++ (GCC) version 4.6.0 (x86_64-unknown-linux-gnu)
    compiled by GNU C version 4.6.0, GMP version 4.3.2, MPFR version 2.4.2, MPC
version 0.8.1
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
GNU C++ (GCC) version 4.6.0 (x86_64-unknown-linux-gnu)
    compiled by GNU C version 4.6.0, GMP version 4.3.2, MPFR version 2.4.2, MPC
version 0.8.1
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: 5005a2e86ab024b8579a7b8cfdb44c26
In file included from
/proj/desrad-c/root/Linux/x86_64/gcc/4.6.0-23A/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.6.0/../../../../include/c++/4.6.0/memory:66:0,
                 from v.cpp:1:
/proj/desrad-c/root/Linux/x86_64/gcc/4.6.0-23A/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.6.0/../../../../include/c++/4.6.0/bits/stl_construct.h:
In function 'void std::_Construct(_T1*, _Args&& ...) [with _T1 =
std::unique_ptr<Foo>, _Args = {const std::unique_ptr<Foo>&}]':
/proj/desrad-c/root/Linux/x86_64/gcc/4.6.0-23A/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.6.0/../../../../include/c++/4.6.0/bits/stl_uninitialized.h:77:3:
  instantiated from 'static _ForwardIterator
std::__uninitialized_copy<_TrivialValueTypes>::__uninit_copy(_InputIterator,
_InputIterator, _ForwardIterator) [with _InputIterator = const
std::unique_ptr<Foo>*, _ForwardIterator = std::unique_ptr<Foo>*, bool
_TrivialValueTypes = false]'
/proj/desrad-c/root/Linux/x86_64/gcc/4.6.0-23A/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.6.0/../../../../include/c++/4.6.0/bits/stl_uninitialized.h:119:41:
  instantiated from '_ForwardIterator std::uninitialized_copy(_InputIterator,
_InputIterator, _ForwardIterator) [with _InputIterator = const
std::unique_ptr<Foo>*, _ForwardIterator = std::unique_ptr<Foo>*]'
/proj/desrad-c/root/Linux/x86_64/gcc/4.6.0-23A/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.6.0/../../../../include/c++/4.6.0/bits/stl_uninitialized.h:259:63:
  instantiated from '_ForwardIterator
std::__uninitialized_copy_a(_InputIterator, _InputIterator, _ForwardIterator,
std::allocator<_Tp>&) [with _InputIterator = const std::unique_ptr<Foo>*,
_ForwardIterator = std::unique_ptr<Foo>*, _Tp = std::unique_ptr<Foo>]'
/proj/desrad-c/root/Linux/x86_64/gcc/4.6.0-23A/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.6.0/../../../../include/c++/4.6.0/bits/stl_vector.h:1113:4:
  instantiated from 'void std::vector<_Tp,
_Alloc>::_M_range_initialize(_ForwardIterator, _ForwardIterator,
std::forward_iterator_tag) [with _ForwardIterator = const
std::unique_ptr<Foo>*, _Tp = std::unique_ptr<Foo>, _Alloc =
std::allocator<std::unique_ptr<Foo> >]'
/proj/desrad-c/root/Linux/x86_64/gcc/4.6.0-23A/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.6.0/../../../../include/c++/4.6.0/bits/stl_vector.h:312:2:
  instantiated from 'std::vector<_Tp,
_Alloc>::vector(std::initializer_list<_Tp>, const allocator_type&) [with _Tp =
std::unique_ptr<Foo>, _Alloc = std::allocator<std::unique_ptr<Foo> >,
std::vector<_Tp, _Alloc>::allocator_type = std::allocator<std::unique_ptr<Foo>
>]'
v.cpp:9:45:   instantiated from here
/proj/desrad-c/root/Linux/x86_64/gcc/4.6.0-23A/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.6.0/../../../../include/c++/4.6.0/bits/stl_construct.h:76:7:
error: use of deleted function 'std::unique_ptr<_Tp, _Dp>::unique_ptr(const
std::unique_ptr<_Tp, _Dp>&) [with _Tp = Foo, _Dp = std::default_delete<Foo>,
std::unique_ptr<_Tp, _Dp> = std::unique_ptr<Foo>]'
/proj/desrad-c/root/Linux/x86_64/gcc/4.6.0-23A/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.6.0/../../../../include/c++/4.6.0/bits/unique_ptr.h:254:7:
error: declared here
salmonj@drdlogin0039.en.desres$

[Bug c++/48728] cannot construct a vector of unique_ptr from an initializer list

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48728

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> 2011-04-22 16:16:26 UTC ---
See Table 100 in the FDIS, X(il) is equivalent to X(il.begin(), il.end()) and
those functions return a const T*, which cannot be moved, so I think the
library is correct and this bug is invalid

[Bug c++/48728] cannot construct a vector of unique_ptr from an initializer list

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48728

Paolo Carlini <paolo.carlini at oracle dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |INVALID

--- Comment #2 from Paolo Carlini <paolo.carlini at oracle dot com> 2011-04-22 16:21:45 UTC ---
I agree.