Why can I prevent implicit conversions for primitives but not user-defined types?

Question

The High Integrity C++ Standards suggest that rvalue arguments to functions can be deleted thus preventing implicit conversions.

http://www.codingstandard.com/rule/8-3-4

Answer 1

There are 3 possible overloads

• 1 is viable.
• 2 is viable
• 3 isn't

2 is better match (template (non exact match) vs regular method (with one user define conversion)).

You may look at http://en.cppreference.com/w/cpp/language/overload_resolution to see a complete set of rules needed