# Extra Clang Tools 18.1.8 documentation

## clang-tidy - bugprone-copy-constructor-init

# bugprone-copy-constructor-init

Finds copy constructors where the constructor doesn’t call the copy constructor of the base class.

    class Copyable {
    public:
      Copyable() = default;
      Copyable(const Copyable &) = default;

      int memberToBeCopied = 0;
    };

    class X2 : public Copyable {
      X2(const X2 &other) {} // Copyable(other) is missing
    };

Also finds copy constructors where the constructor of the base class don’t have parameter.

    class X3 : public Copyable {
      X3(const X3 &other) : Copyable() {} // other is missing
    };

Failure to properly initialize base class sub-objects during copy construction can result in undefined behavior, crashes, data corruption, or other unexpected outcomes. The check ensures that the copy constructor of a derived class properly calls the copy constructor of the base class, helping to prevent bugs and improve code quality.

Limitations:

- It won’t generate warnings for empty classes, as there are no class members (including base class sub-objects) to worry about.

- It won’t generate warnings for base classes that have copy constructor private or deleted.

- It won’t generate warnings for base classes that are initialized using other non-default constructor, as this could be intentional.

The check also suggests a fix-its in some cases.