Unused parameters should be unnamed

Reason

Readability. Suppression of unused parameter warnings.

Example

widget* find(const set<widget>& s, const widget& w, Hint);   // once upon a time, a hint was used

Note

Allowing parameters to be unnamed was introduced in the early 1980s to address this problem.

If parameters are conditionally unused, declare them with the [[maybe_unused]] attribute. For example:

template <typename Value>
Value* find(const set<Value>& s, const Value& v, [[maybe_unused]] Hint h)
{
    if constexpr (sizeof(Value) > CacheSize)
    {
        // a hint is used only if Value is of a certain size
    }
}

Enforcement

Flag named unused parameters.