MISRA.SPEC.ILL

Explicit instantiation of a template makes the code ill-formed.

MISRA-C++ Rule 14-7-2 (required): For any given template specialization, an explicit instantiation of the template with the template-arguments used in the specialization shall not render the program ill-formed.

Rationale

An implicit template specialization does not instantiate every member of the template. Where instantiation of a member would result in an ill-formed program it is not clear that the template should be used with the supplied template-arguments.

Example

template <typename T>
class A
{
public:
   void f1 ()
   {
      // ...
   }
   void f2 ()
   {
      T t;
      t.x = 0;   // Will only work for types that have a .x member
   }
};
void b ()
{
   A<int32_t> a; // A<int32_t>::f2 is not instantiated.
   a.f1 ();
}
template class A<int32_t>;  // Non-compliant - instantiation of f2
                            // results in "ill-formed" program.