`A8-4-7`: Exclude user defined operators from this rule

[lcartey]

Affected rules

• A8-4-7

Description

User defined operators are expected to conform to a particular prototype, and should not be flagged by this rule.

We should also consider whether there are any other examples of fixed prototype functions that might be erroneously reported by theis rule.

Example

class some_base_class {
 public:
  constexpr some_base_class() noexcept = default;
  constexpr std::size_t size() const noexcept { return 0; }

 protected:
...
  some_base_class& operator=(const some_base_class&) = default; // error here
};