id	summary	reporter	owner	description	type	status	milestone	component	version	severity	resolution	keywords	cc
11922	Rev f4a61d breaks introduces ambiguity.	layus	John Maddock	"The following code used to work before 1.60.

{{{
#include <memory>
#include <boost/multiprecision/cpp_int.hpp>
typedef boost::multiprecision::cpp_int mp_int;

class Int {
  public:
    Int(const mp_int& i) {};
    Int(const Int& i) = delete;
};

int main() {
    mp_int i(10);
    std::shared_ptr<Int> p = std::make_shared<Int>(i + 10);
    return 0;
}
}}}

But the changes introduced by the following commit, merged into boost-1.60.0, breaks it.
The compiler cannot pick the constructor because there is some ambiguity.
(i.e. ""call of overloaded ‘Int(...)’ is ambiguous"")

{{{
commit f4a61d5f47c4b03e2c0d3f2bed55fe8f7bb07620
Author: jzmaddock <XXX>
Date:   Thu Mar 12 17:55:13 2015 +0000

    Add explicit conversion operators and tests to expression templates.

}}}

I must admit I am not even sure why there is ambiguity, but since the only way to call Int(const Int&) is to call Int(const mp_int&) first to get an Int there should be no ambiguity for the compiler here.
"	Bugs	closed	To Be Determined	multiprecision	Boost 1.60.0	Regression	fixed		jzmaddock