Dangers of using an implicit string conversion operator?

Question

What are the dangers of using an implicit string conversion operator in a custom string class?

class MyString
{
public:

   ...

   inline operator string() const { return str; }

private:
   std::string str;
};

Answer 1

The main "danger" of implicit conversion is mostly: You might get an unexpected conversion.

If your string class can logically be used as a std::string, I do not think there is a problem.