Implement GetHashCode() via HashCode.Combine()

Extensions/Xtensive.Orm.Security/Permission.cs

@@ -56,16 +56,7 @@ public override bool Equals(object obj)
     }
 
     /// <inheritdoc/>
-    public override int GetHashCode()
-    {
-      unchecked {
-        int result = (Type != null ? Type.GetHashCode() : 0);
-        result = (result*397) ^ CanRead.GetHashCode();
-        result = (result*397) ^ CanWrite.GetHashCode();
-        result = (result*397) ^ (Query != null ? Query.GetHashCode() : 0);
-        return result;
-      }
-    }
+    public override int GetHashCode() => HashCode.Combine(Type, CanRead, CanWrite, Query);
 
     #endregion
 

Orm/Xtensive.Orm.Tests.Core/Caching/CachePerformanceTest.cs

@@ -52,10 +52,7 @@ public override bool Equals(object obj)
         return Equals(obj as Item);
       }
 
-      public override int GetHashCode()
-      {
-        return (Value!=null ? Value.GetHashCode() : 0);
-      }
+      public override int GetHashCode() => Value?.GetHashCode() ?? 0;
 
       public override string ToString()
       {
@@ -174,4 +171,4 @@ private void FetchTest(int count)
       }
     }
   }
-}
+}

Orm/Xtensive.Orm.Tests.Core/Caching/WeakestCacheTest.cs

@@ -36,10 +36,7 @@ public override bool Equals(object obj)
         return Equals(obj as Item);
       }
 
-      public override int GetHashCode()
-      {
-        return (Value != null ? Value.GetHashCode() : 0);
-      }
+      public override int GetHashCode() => Value?.GetHashCode() ?? 0;
 
       public override string ToString()
       {
@@ -197,4 +194,4 @@ public void ProfileTest()
       }
     }
   }
-}
+}

Orm/Xtensive.Orm.Tests.Core/Modelling/IndexingModel/TypeInfo.cs

@@ -100,19 +100,7 @@ public override bool Equals(object obj)
     }
 
     /// <inheritdoc/>
-    public override int GetHashCode()
-    {
-      unchecked {
-        int result = (Type!=null ? Type.GetHashCode() : 0);
-        result = (result * 397) ^ (IsNullable ? 1 : 0);
-        result = (result * 397) ^ Length;
-        result = (result * 397) ^ Scale;
-        result = (result * 397) ^ Precision;
-        if (Culture!=null)
-          result = (result * 397) ^ Culture.GetHashCode();
-        return result;
-      }
-    }
+    public override int GetHashCode() => HashCode.Combine(Type, IsNullable, Length, Scale, Precision, Culture);
 
     /// <summary>
     /// Implements the operator ==.
@@ -216,4 +204,4 @@ public TypeInfo(Type type, bool isNullable, int length, int scale, int precision
       Precision = precision;
     }
   }
-}
+}

Orm/Xtensive.Orm.Tests.Framework/Dynamic.cs

@@ -219,11 +219,13 @@ internal class Signature : IEquatable<Signature>
     public Signature(IEnumerable<DynamicProperty> properties)
     {
       this.properties = properties.ToArray();
-      hashCode = 0;
+      HashCode hc = new();
       foreach (DynamicProperty p in properties)
       {
-        hashCode ^= p.Name.GetHashCode() ^ p.Type.GetHashCode();
+        hc.Add(p.Name);
+        hc.Add(p.Type);
       }
+      hashCode = hc.ToHashCode();
     }
 
     #region IEquatable<Signature> Members
@@ -241,10 +243,7 @@ public bool Equals(Signature other)
 
     #endregion
 
-    public override int GetHashCode()
-    {
-      return hashCode;
-    }
+    public override int GetHashCode() => hashCode;
 
     public override bool Equals(object obj)
     {
@@ -2298,4 +2297,4 @@ internal static class Res
     public const string CloseBracketOrCommaExpected = "']' or ',' expected";
     public const string IdentifierExpected = "Identifier expected";
   }
-}
+}

Orm/Xtensive.Orm.Tests/Linq/LocalCollectionsTest.cs

@@ -54,10 +54,7 @@ public override bool Equals(object obj)
       return Equals((Poco<T>) obj);
     }
 
-    public override int GetHashCode()
-    {
-      return Value.GetHashCode();
-    }
+    public override int GetHashCode() => Value.GetHashCode();
   }
 
   public class Poco<T1, T2>
@@ -85,12 +82,7 @@ public override bool Equals(object obj)
       return Equals((Poco<T1, T2>) obj);
     }
 
-    public override int GetHashCode()
-    {
-      unchecked {
-        return (Value1.GetHashCode() * 397) ^ Value2.GetHashCode();
-      }
-    }
+    public override int GetHashCode() => HashCode.Combine(Value1, Value2);
 
     public Poco(T1 Value1, T2 Value2)
     {
@@ -137,15 +129,7 @@ public override bool Equals(object obj)
       return Equals((Poco<T1, T2, T3>) obj);
     }
 
-    public override int GetHashCode()
-    {
-      unchecked {
-        int result = Value1.GetHashCode();
-        result = (result * 397) ^ Value2.GetHashCode();
-        result = (result * 397) ^ Value3.GetHashCode();
-        return result;
-      }
-    }
+    public override int GetHashCode() => HashCode.Combine(Value1, Value2, Value3);
 
     public Poco()
     {
@@ -942,4 +926,4 @@ private IEnumerable<Poco<int, decimal, string>> GetLocalItems(int count)
         .ToList();
     }
   }
-}
+}

Orm/Xtensive.Orm/Annotations.cs

@@ -75,10 +75,7 @@ public override bool Equals(object obj)
     /// Returns the hash code for this instance.
     /// </summary>
     /// <returns>A hash code for the current <see cref="LocalizationRequiredAttribute"/>.</returns>
-    public override int GetHashCode()
-    {
-      return base.GetHashCode();
-    }
+    public override int GetHashCode() => base.GetHashCode();
   }
 
   /// <summary>
@@ -521,4 +518,4 @@ public PathReferenceAttribute([PathReference] string basePath)
 
     [UsedImplicitly] public string BasePath { get; private set; }
   }
-}
+}

Orm/Xtensive.Orm/Arithmetic/ArithmeticRules.cs

@@ -45,10 +45,7 @@ public override bool Equals(object obj) =>
       obj is ArithmeticRules other && Equals(other);
 
     /// <inheritdoc/>
-    public override int GetHashCode()
-    {
-      return ((byte)overflowBehavior << 8) | (byte)nullBehavior;
-    }
+    public override int GetHashCode() => ((byte) overflowBehavior << 8) | (byte) nullBehavior;
 
 
     // Constructors

Orm/Xtensive.Orm/Caching/WeakestCache.cs

@@ -101,10 +101,7 @@ public override bool Equals(object obj)
         return Equals((WeakEntry) obj);
       }
 
-      public override int GetHashCode()
-      {
-        return hashCode;
-      }
+      public override int GetHashCode() => hashCode;
 
       #endregion
 

Orm/Xtensive.Orm/Collections/FlagCollection.cs

@@ -333,12 +333,7 @@ public override bool Equals(object obj)
     }
 
     /// <inheritdoc/>
-    public override int GetHashCode()
-    {
-      int result = keys.GetHashCode();
-      result = 29*result + flags.GetHashCode();
-      return result;
-    }
+    public override int GetHashCode() => HashCode.Combine(keys, flags);
 
     #endregion
 
@@ -407,4 +402,4 @@ public virtual void GetObjectData(SerializationInfo info, StreamingContext conte
 
     #endregion
   }
-}
+}

Orm/Xtensive.Orm/Collections/TypeRegistration.cs

@@ -69,15 +69,7 @@ public override bool Equals(object obj)
     }
 
     /// <inheritdoc/>
-    public override int GetHashCode()
-    {
-      unchecked {
-        int result = (type!=null ? type.GetHashCode() : 0);
-        result = (result * 397) ^ (assembly!=null ? assembly.GetHashCode() : 0);
-        result = (result * 397) ^ (@namespace!=null ? @namespace.GetHashCode() : 0);
-        return result;
-      }
-    }
+    public override int GetHashCode() => HashCode.Combine(type, assembly, @namespace);
 
     /// <inheritdoc/>
     public static bool operator ==(TypeRegistration left, TypeRegistration right)
@@ -128,4 +120,4 @@ public TypeRegistration(Assembly assembly, string @namespace)
       this.@namespace = @namespace;
     }
   }
-}
+}

Orm/Xtensive.Orm/Comparison/ComparisonRule.cs

@@ -83,13 +83,7 @@ public override bool Equals(object obj) =>
       obj is ComparisonRule other && Equals(other);
 
     /// <inheritdoc/>
-    public override int GetHashCode()
-    {
-      int result = (int)Direction;
-      if (Culture != null)
-        result ^= Culture.GetHashCode();
-      return result;
-    }
+    public override int GetHashCode() => HashCode.Combine(Direction, Culture);
 
     #endregion
 
@@ -200,4 +194,4 @@ void ISerializable.GetObjectData(SerializationInfo info, StreamingContext contex
       info.AddValue(nameof(Culture), cultureId);
     }
   }
-}
+}

Orm/Xtensive.Orm/Comparison/ComparisonRules.cs

@@ -23,7 +23,7 @@ public sealed class ComparisonRules :
   {
     private readonly ComparisonRule    value;
     private readonly ComparisonRules[] composite;
-    private volatile int cachedHashCode;
+    private long cachedHashCode;
 
     /// <summary>
     /// Predefined rules with <see cref="Direction"/> = <see cref="Direction.None"/>.
@@ -199,18 +199,20 @@ public override bool Equals(object obj) =>
     /// <inheritdoc/>
     public override int GetHashCode()
     {
-      if (cachedHashCode==0) lock (composite) if (cachedHashCode==0) {
+      var h = Volatile.Read(ref cachedHashCode);
+      if (h == 0) {
         int tailIndex = TailIndex;
-        int result = value.GetHashCode();
-        if (tailIndex==0 && IsRecursive)
-          result ^= 29 * 22; // Hash affection by IsRecursive
+        HashCode hc = new();
+        hc.Add(value);
+        if (tailIndex == 0 && IsRecursive)
+          hc.Add(1); // Hash affection by IsRecursive
         else
-          result ^= 29 * composite[tailIndex].GetHashCode();
+          hc.Add(composite[tailIndex]);
         for (int i = 0; i < tailIndex; i++)
-          result ^= (composite[i].GetHashCode() << i);
-        cachedHashCode = result;
+          hc.Add(composite[i]);
+        Volatile.Write(ref cachedHashCode, (long)hc.ToHashCode() | (1L << 63)); // Set the highest bit as HasValue flag even when `hashCode == 0`
       }
-      return cachedHashCode;
+      return (int) h;
     }
 
     #endregion
@@ -313,4 +315,4 @@ private ComparisonRules(ComparisonRule value, ComparisonRules[] composite, bool
       this.composite = composite;
     }
   }
-}
+}

Orm/Xtensive.Orm/Comparison/Internals/NoSystemComparerHandler.cs

@@ -36,13 +36,11 @@ public bool Equals(T other)
     }
 
     /// <exception cref="NotSupportedException"><c>NotSupportedException</c>.</exception>
-    public override int GetHashCode()
-    {
+    public override int GetHashCode() =>
       throw new NotSupportedException(string.Format(
         Strings.ExTypeXMustImplementY,
         typeof(T).GetShortName(),
         typeof(IEquatable<T>).GetShortName()));
-    }
 
 
     // Constructors
@@ -51,4 +49,4 @@ private NoSystemComparerHandler()
     {
     }
   }
-}
+}

Orm/Xtensive.Orm/Conversion/Biconverter.cs

@@ -57,12 +57,7 @@ public override bool Equals(object obj) =>
       obj is Biconverter<TFrom, TTo> other && Equals(other);
 
     /// <inheritdoc/>
-    public override int GetHashCode()
-    {
-      unchecked {
-        return ((ConvertForward!=null ? ConvertForward.GetHashCode() : 0) * 397) ^ (ConvertBackward!=null ? ConvertBackward.GetHashCode() : 0);
-      }
-    }
+    public override int GetHashCode() => HashCode.Combine(ConvertForward, ConvertBackward);
 
     #endregion
 

Orm/Xtensive.Orm/Core/HasVersion{TValue,TVersion}.cs

@@ -61,14 +61,7 @@ public override bool Equals(object obj) =>
       obj is HasVersion<TValue, TVersion> other && Equals(other);
 
     /// <inheritdoc/>
-    public override int GetHashCode()
-    {
-      unchecked {
-        return 
-          ((Value!=null ? Value.GetHashCode() : 0) * 397) ^ 
-          (Version!=null ? Version.GetHashCode() : 0);
-      }
-    }
+    public override int GetHashCode() => HashCode.Combine(Value, Version);
 
     /// <summary>
     /// Checks specified objects for equality.
@@ -114,4 +107,4 @@ public HasVersion(TValue value, TVersion version)
       Version = version;
     }
   }
-}
+}

Orm/Xtensive.Orm/Core/Pair{TFirst,TSecond}.cs

@@ -57,12 +57,7 @@ public override bool Equals(object obj) =>
       obj is Pair<TFirst, TSecond> other && Equals(other);
 
     /// <inheritdoc/>
-    public override int GetHashCode()
-    {
-      unchecked {
-        return ((First?.GetHashCode() ?? 0) * 397) ^ (Second?.GetHashCode() ?? 0);
-      }
-    }
+    public override int GetHashCode() => HashCode.Combine(First, Second);
 
     /// <summary>
     /// Checks specified objects for equality.