MISRA.NS.USING_DECL

Multiple declarations for identifier straddle using-declaration for that identifier.

MISRA-C++ Rule 7-3-5 (required): Multiple declarations for an identifier in the same namespace shall not straddle a using-declaration for that identifier.

Rationale

The set of identifiers introduced by a using-declaration does not include any declarations that may be added by a subsequent declaration in the namespace. Any subsequent declarations will not be found through the using-declaration, which may not be consistent with developer expectations.

Example

namespace NS1
{
   void f( uint16_t ); // Example 1
}
using NS1::f;

namespace NS1
{
   void f( uint32_t ); // Example 2 — Non-compliant
}
void bar()
{
   f( 0U );
}

In the above example, moving the using-declaration below the second namespace would result in Example 2 being called, as it is a better match than Example 1.