* pt.c (convert_nontype_argument): Don't call
	build_converted_constant_expr if it could involve calling a conversion
	function with a instantiation-dependent constructor as its argument.

	* g++.dg/cpp0x/constexpr-conv3.C: New test.
	* g++.dg/cpp0x/constexpr-conv4.C: New test.

From-SVN: r270178