BUG: Full Koenig Lookup Works Only for Operators

View products that this article applies to.

This article was previously published under Q242190

Expand all | Collapse all

SYMPTOMS

Argument-dependent name lookup, also known as Koenig lookup, works only for operators and not regular functions in a namespace.

Back to the top

The compiler does not fully support argument-dependent name lookup as specified in the C++ Standard. Please refer to the C++ Standard, section 3.4.2, for information on argument-dependent name lookup.

Back to the top

STATUS

Microsoft has confirmed that this is a bug in the Microsoft products that are listed at the beginning of this article.

Back to the top

MORE INFORMATION

Steps to Reproduce Behavior

The following code example demonstrates the error:

//test.cpp
// compiler option needed:/GX  
#include <iostream>
namespace N1 {
	struct T1 {
	};
	void g(T1) {
	}
 	T1 operator+( T1 x, T1 y) {
		std::cout<< "In N1::+" <<std::endl;
		return y;
	}
}

int main() {
	N1::T1 t1 ,t2;
	g(t1);	// error C2065: 'g' : undeclared identifier
	t1 + t2; // works fine calls N1::operator+
	return 0;
}

Back to the top