<html>

    <head>

      <base href="https://llvm.org/bugs/" />

    </head>

    <body><table border="1" cellspacing="0" cellpadding="8">

        <tr>

          <th>Bug ID</th>

          <td><a class="bz_bug_link 

          bz_status_NEW "

   title="NEW --- - "error: default initialization of an object of const type 'const Z' requires a user-provided default constructor" even when no constructor needed."

   href="https://llvm.org/bugs/show_bug.cgi?id=23381">23381</a>

          </td>

        </tr>

        <tr>

          <th>Summary</th>

          <td>"error: default initialization of an object of const type 'const Z' requires a user-provided default constructor" even when no constructor needed.

          </td>

        </tr>

        <tr>

          <th>Product</th>

          <td>compiler-rt

          </td>

        </tr>

        <tr>

          <th>Version</th>

          <td>3.4

          </td>

        </tr>

        <tr>

          <th>Hardware</th>

          <td>PC

          </td>

        </tr>

        <tr>

          <th>OS</th>

          <td>Linux

          </td>

        </tr>

        <tr>

          <th>Status</th>

          <td>NEW

          </td>

        </tr>

        <tr>

          <th>Severity</th>

          <td>normal

          </td>

        </tr>

        <tr>

          <th>Priority</th>

          <td>P

          </td>

        </tr>

        <tr>

          <th>Component</th>

          <td>compiler-rt

          </td>

        </tr>

        <tr>

          <th>Assignee</th>

          <td>unassignedbugs@nondot.org

          </td>

        </tr>

        <tr>

          <th>Reporter</th>

          <td>daniel.black@openquery.com.au

          </td>

        </tr>

        <tr>

          <th>CC</th>

          <td>llvmbugs@cs.uiuc.edu

          </td>

        </tr>

        <tr>

          <th>Classification</th>

          <td>Unclassified

          </td>

        </tr></table>

      <p>

        <div>

        <pre>"error: default initialization of an object of const type 'const Z' requires a

user-provided default constructor" even when no constructor needed.

<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#253">http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#253</a>

$ cat  >  /tmp/x.cc

  struct Z {

        // no data members

        operator int() const { return 0; }

    };

    void f() {

        const Z z1;         // ill-formed: no initializer

        const Z z2 = { };   // well-formed

    }

$ clang++ -c /tmp/x.cc

/tmp/x.cc:7:17: error: default initialization of an object of const type 'const

Z' requires a user-provided default constructor

        const Z z1;         // ill-formed: no initializer

                ^

1 error generated.

g++ compiles without error

clang++ --version

clang version 3.4.2 (tags/RELEASE_34/dot2-final)

Target: x86_64-redhat-linux-gnu

Thread model: posix

g++ (GCC) 4.8.3 20140911 (Red Hat 4.8.3-7)

This is free software; see the source for copying conditions.  There is NO

warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.</pre>

        </div>

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