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  1. using System;
  2. using System.Collections.Generic;
  3.  
  4. internal class GenericEqualityComparer<T> : EqualityComparer<T> where T : IEquatable<T>
  5. {
  6.     public override bool Equals(T x, T y)
  7.     {
  8.         if (x != null)
  9.         {
  10.             if (y != null) return x.Equals(y);
  11.             return false;
  12.         }
  13.         if (y != null) return false;
  14.         return true;
  15.     }
  16.  
  17.     public override int GetHashCode(T obj) => obj?.GetHashCode() ?? 0;
  18.  
  19.     // ...
  20. }
  21.  
  22. internal struct Foo : IEquatable<Foo>
  23. {
  24.     public bool Equals(Foo other)
  25.     {
  26.         Console.WriteLine("Equals(Foo other)");
  27.         return true;
  28.     }
  29.  
  30.     public override bool Equals(object obj)
  31.     {
  32.         Console.WriteLine("Equals(object obj)");
  33.         return true;
  34.     }
  35.  
  36.     public override int GetHashCode() => 0;
  37. }
  38.  
  39. internal static class Program
  40. {
  41.     private static void Main()
  42.     {
  43.         var comparer = new GenericEqualityComparer<Foo>();
  44.         var x = new Foo();
  45.         var y = new Foo();
  46.         var equal = comparer.Equals(x, y);
  47.         Console.WriteLine(equal);
  48.     }
  49. }
  50.  
Success #stdin #stdout 0.02s 29800KB
comments (?)
stdin 
Standard input is empty
stdout 
Equals(Foo other)
True
https://ideone.com/9tlRqT
language:
C# (gmcs 5.20.1)
created:
7 years ago
visibility:
public

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