22b4470f2a
Update all links to C++ Core Guidelines to `e49158a`.
Refresh done using the following script and some manual edits:
db76e34e74/personal/fred-tingaud/rspec/refresh-cppcoreguidelines.py
When re-using this script, be mindful that:
- it does not cover `shared_content`
- it does not properly escape inline code in links (e.g., "[=]" or "`mutex`es")
- it does not change `C++` to `{cpp}` in link titles.
Co-authored-by: Marco Borgeaud <marco.borgeaud@sonarsource.com>
80 lines
2.1 KiB
Plaintext
80 lines
2.1 KiB
Plaintext
== Why is this an issue?
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When inheriting from a class, if you need to inherit its constructors without additional initialization you should prefer ``++using-declaration++`` to inherit all base class's constructors instead of writing them by hand.
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``++using-declaration++`` for inheriting constructor is a {cpp}11 feature that makes all constructors of the base visible to the overload resolution when initializing the derived class.
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If you need to change the accessibility of one of the inherited constructors, you can do it by keeping the ``++using-declaration++`` and declaring that constructor explicitly as private:
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----
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class Base {
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public:
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Base(int p) {}
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Base(int p1, int p2) {}
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};
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class Derived : public Base {
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using Base::Base;
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Derived(int p1, int p2); // Changes constructor to private accessibility
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};
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int f(){
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Derived b(1); // Base(int p) is visible when initializing the derived class
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Derived b1(1,2); // Compilation error: Base(int p1, int p2) is not visible when initializing the derived class
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}
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----
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This rule raises an issue when a constructor inherits the base class constructor without requiring any additional initialization.
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=== Noncompliant code example
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[source,cpp]
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----
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class Base {
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public:
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Base(int p) {}
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};
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class Derived : public Base {
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public:
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Derived(int p) : Base(p) {} // Noncompliant
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};
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----
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=== Compliant solution
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[source,cpp]
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----
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class Base {
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public:
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Base(int p) {}
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};
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class Derived : public Base {
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using Base::Base;
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};
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----
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== Resources
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* {cpp} Core Guidelines - https://github.com/isocpp/CppCoreGuidelines/blob/e49158a/CppCoreGuidelines.md#c52-use-inheriting-constructors-to-import-constructors-into-a-derived-class-that-does-not-need-further-explicit-initialization[C.52: Use inheriting constructors to import constructors into a derived class that does not need further explicit initialization]
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ifdef::env-github,rspecator-view[]
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'''
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== Implementation Specification
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(visible only on this page)
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=== Message
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Replace inherited constructors without additional initialization by a "using" declaration.
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endif::env-github,rspecator-view[]
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