// if not overloaded, would be RvalueDatumExpr
let arg = unpack_datum!(bcx, trans(bcx, &**subexpr));
trans_overloaded_op(bcx, expr, MethodCall::expr(expr.id),
// if not overloaded, would be RvalueDatumExpr
let arg = unpack_datum!(bcx, trans(bcx, &**subexpr));
trans_overloaded_op(bcx, expr, MethodCall::expr(expr.id),