[Bug c++/56976] New: using braces to initialize a reference forces copy construction

[akim.demaille at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56976



             Bug #: 56976

           Summary: using braces to initialize a reference forces copy

                    construction

    Classification: Unclassified

           Product: gcc

           Version: 4.8.0

            Status: UNCONFIRMED

          Severity: normal

          Priority: P3

         Component: c++

        AssignedTo: unassig...@gcc.gnu.org

        ReportedBy: akim.demai...@gmail.com





Hi all,



I hope this is not yet another buggy bug report.  I have browsed the draft (I

don't have the current standard), and saw nothing clear cut, yet the principle

of least surprise tends to think this is really a bug.



Below, using braces to initialize a const-ref forces a call to a

copy-constructor.  clang compiles this without error/warning.  Cheers!





$ cat bar.cc

struct bar

{

  bar() = default;

  bar(const bar&) = delete;

};



int main()

{

  bar b;

  const bar& b1_(b);

  const bar& b2_{b};

}

$ g++-mp-4.8 -std=c++11 -Wall -Wno-unused-variable bar.cc

bar.cc: In function 'int main()':

bar.cc:11:19: error: use of deleted function 'bar::bar(const bar&)'

   const bar& b2_{b};

                   ^

bar.cc:4:3: error: declared here

   bar(const bar&) = delete;

   ^

$ clang++-mp-3.2 -std=c++11 -Wall bar.cc -Wno-unused-variable

$