16f6c0aecf
Inline adoc files when they are included exactly once. Also fix language tags because this inlining gives us better information on what language the code is written in.
75 lines
1.9 KiB
Plaintext
75 lines
1.9 KiB
Plaintext
== Why is this an issue?
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When you implement ``++IComparable++`` or ``++IComparable<T>++`` on a class you should also override ``++Equals(object)++`` and overload the comparison operators (``++==++``, ``++!=++``, ``++<++``, ``++<=++``, ``++>++``, ``++>=++``). That's because the CLR cannot automatically call your ``++CompareTo++`` implementation from ``++Equals(object)++`` or from the base comparison operator implementations. Additionally, it is best practice to override ``++GetHashCode++`` along with ``++Equals++``.
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This rule raises an issue when a class implements ``++IComparable++`` without also overriding ``++Equals(object)++`` and the comparison operators.
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=== Noncompliant code example
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[source,csharp]
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----
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public class Foo: IComparable // Noncompliant
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{
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public int CompareTo(object obj) { /* ... */ }
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}
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----
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=== Compliant solution
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[source,csharp]
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----
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public class Foo: IComparable
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{
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public int CompareTo(object obj) { /* ... */ }
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public override bool Equals(object obj)
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{
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var other = obj as Foo;
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if (object.ReferenceEquals(other, null))
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{
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return false;
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}
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return this.CompareTo(other) == 0;
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}
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public int GetHashCode() { /* ... */ }
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public static bool operator == (Foo left, Foo right)
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{
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if (object.ReferenceEquals(left, null))
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{
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return object.ReferenceEquals(right, null);
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}
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return left.Equals(right);
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}
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public static bool operator > (Foo left, Foo right)
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{
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return Compare(left, right) > 0;
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}
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public static bool operator < (Foo left, Foo right)
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{
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return Compare(left, right) < 0;
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}
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public static bool operator != (Foo left, Foo right)
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{
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return !(left == right);
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}
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}
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----
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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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When implementing {0}, you should also override {1}.
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'''
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== Comments And Links
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(visible only on this page)
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include::../comments-and-links.adoc[]
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endif::env-github,rspecator-view[]
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