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POCompile error when calling a move overloaded function with an implicitly convertible object
 

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  1. POCompile error when calling a move overloaded function with an implicitly convertible object
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    <p>This program does not compile using <code>clang++ test.cpp -std=c++0x</code>:</p> <pre><code>class A { public: A() {} A(const A&amp;) {} A(A&amp;&amp;) {} A&amp; operator = (const A&amp;) { return *this; } A&amp; operator = (A&amp;&amp;) { return *this; } }; class B { A m_a; public: operator const A &amp;() const { return m_a; } }; int main(int, char**) { A a; B b; a = b; // compile error } </code></pre> <p>Compile errors: </p> <pre><code>Apple clang version 3.0 (tags/Apple/clang-211.10.1) (based on LLVM 3.0svn) test.cpp:25:9: error: no viable conversion from 'B' to 'A' a = b; ^ test.cpp:5:5: note: candidate constructor not viable: no known conversion from 'B' to 'const A &amp;' for 1st argument A(const A&amp;) {} ^ test.cpp:6:5: note: candidate constructor not viable: no known conversion from 'B' to 'A &amp;&amp;' for 1st argument A(A&amp;&amp;) {} ^ test.cpp:15:5: note: candidate function operator const A &amp;() const ^ test.cpp:8:23: note: passing argument to parameter here A&amp; operator = (A&amp;&amp;) { return *this; } ^ </code></pre> <p>Why does it not compile? Why does the compiler prefer <code>A::operator&nbsp;=&nbsp;(A&amp;&amp;)</code> over <code>A::operator&nbsp;=&nbsp;(const A&amp;)</code>?</p> <p>In addition, why would <code>A a = b;</code> compile while both <code>A a; a = b;</code> (the above program) and <code>A a(b);</code> do not?</p>
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    1. USDavid Lin
    1. USDavid Lin
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      1. POCompile error when calling a move overloaded function with an implicitly convertible object
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      1. VTUpMod
    2. VO
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    3. VO
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      1. POCompile error when calling a move overloaded function with an implicitly convertible object
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      1. VTUpMod
    1. COWhat version of Clang?
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      1. POCompile error when calling a move overloaded function with an implicitly convertible object
      1. USildjarn
    2. COFWIW, your code compiles as-is with `clang version 3.0 (tags/RELEASE_30/final) Target: x86_64-pc-linux-gnu Thread model: posix` and GCC 4.5.3 or 4.6.2 (but I have no idea if that is normal or not)
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      1. POCompile error when calling a move overloaded function with an implicitly convertible object
      1. USMat
    3. COSeems like clang bug.
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      1. USMr.Anubis
 

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