Synopsis: [2003-01-01]c++ ignores cast operator State-Changed-From-To: analyzed->closed State-Changed-By: bajo State-Changed-When: Mon May 5 01:14:02 2003 State-Changed-Why: Not a bug. "a1 = (A1)a2" is a type conversion in cast notation (§5.4). "a1 = const_cast(a2)" is ill-formed, but "a1 = static_cast(a2)" is well-formed, because "a1 = A1(a2)" is well-formed (this is the exact condition specified by §5.2.9p2). Thus, for §5.4p5, the cast notation is equivalent to the static_cast notation. The static_cast notation is then equivalent to "a1 = A1(a2)", which upcasts a2 to const A& implicitally, and then invokes A1(const A&). G++ behaves exactly as the standard prescribes, and all the other compilers I have agree. If you need to force the use of the custom conversion operator, you can still do it using the syntax "a1 = a2.operator A1()". http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=4337