Fix and simplify combined hashcodes

Core/Relationships/RelationshipResolver.cs

@@ -851,24 +851,23 @@ public bool Equals(SelectionReason rsn)
 
         public override int GetHashCode()
         {
-            var typeCode = GetType().GetHashCode();
+            var type = GetType();
             // Parent throws in some derived classes
             try
             {
                 #if NET5_0_OR_GREATER
-                return HashCode.Combine(typeCode,
-                                        Parent.GetHashCode());
+                return HashCode.Combine(type, Parent);
                 #else
                 unchecked
                 {
-                    return (typeCode * 397) ^ Parent.GetHashCode();
+                    return (type, Parent).GetHashCode();
                 }
                 #endif
             }
             catch
             {
                 // If thrown, then we're type-only
-                return typeCode;
+                return type.GetHashCode();
             }
         }
 

Core/Types/CkanModule.cs

@@ -688,12 +688,7 @@ private static bool RelationshipsAreEquivalent(List<RelationshipDescriptor> a, L
         }
 
         public override int GetHashCode()
-        {
-            unchecked
-            {
-                return (identifier.GetHashCode() * 397) ^ version.GetHashCode();
-            }
-        }
+            => (identifier, version).GetHashCode();
 
         bool IEquatable<CkanModule>.Equals(CkanModule other)
             => Equals(other);

Core/Versioning/GameVersion.cs

@@ -589,19 +589,12 @@ public sealed partial class GameVersion : IEquatable<GameVersion>
         /// of the <see cref="obj"/> parameter; otherwise, <c>false</c>.
         /// </returns>
         public bool Equals(GameVersion obj)
-        {
-            if (obj is null)
-            {
-                return false;
-            }
-
-            if (ReferenceEquals(obj, this))
-            {
-                return true;
-            }
-
-            return _major == obj._major && _minor == obj._minor && _patch == obj._patch && _build == obj._build;
-        }
+            => !(obj is null)
+                && (ReferenceEquals(obj, this)
+                    || (_major == obj._major
+                        && _minor == obj._minor
+                        && _patch == obj._patch
+                        && _build == obj._build));
 
         /// <summary>
         /// Returns a value indicating whether the current <see cref="GameVersion"/> object is equal to a specified
@@ -616,41 +609,19 @@ public bool Equals(GameVersion obj)
         /// matches the corresponding component of <see cref="obj"/>; otherwise, <c>false</c>.
         /// </returns>
         public override bool Equals(object obj)
-        {
-            if (obj is null)
-            {
-                return false;
-            }
-
-            if (ReferenceEquals(obj, this))
-            {
-                return true;
-            }
-
-            return obj is GameVersion gv && Equals(gv);
-        }
+            => !(obj is null)
+                && (ReferenceEquals(obj, this)
+                    || (obj is GameVersion gv && Equals(gv)));
 
         /// <summary>
         /// Returns a hash code for the current <see cref="GameVersion"/> object.
         /// </summary>
         /// <returns>A 32-bit signed integer hash code.</returns>
         public override int GetHashCode()
         #if NET5_0_OR_GREATER
-            => HashCode.Combine(_major.GetHashCode(),
-                                _minor.GetHashCode(),
-                                _patch.GetHashCode(),
-                                _build.GetHashCode());
+            => HashCode.Combine(_major, _minor, _patch, _build);
         #else
-        {
-            unchecked
-            {
-                var hashCode = _major.GetHashCode();
-                hashCode = (hashCode*397) ^ _minor.GetHashCode();
-                hashCode = (hashCode*397) ^ _patch.GetHashCode();
-                hashCode = (hashCode*397) ^ _build.GetHashCode();
-                return hashCode;
-            }
-        }
+            => (_major, _minor, _patch, _build).GetHashCode();
         #endif
 
         /// <summary>
@@ -660,9 +631,7 @@ public override int GetHashCode()
         /// <param name="v2">The second <see cref="GameVersion"/> object.</param>
         /// <returns><c>true</c> if <see cref="v1"/> equals <see cref="v2"/>; otherwise, <c>false</c>.</returns>
         public static bool operator ==(GameVersion v1, GameVersion v2)
-        {
-            return Equals(v1, v2);
-        }
+            => Equals(v1, v2);
 
         /// <summary>
         /// Determines whether two specified <see cref="GameVersion"/> objects are not equal.
@@ -673,9 +642,7 @@ public override int GetHashCode()
         /// <c>true</c> if <see cref="v1"/> does not equal <see cref="v2"/>; otherwise, <c>false</c>.
         /// </returns>
         public static bool operator !=(GameVersion v1, GameVersion v2)
-        {
-            return !Equals(v1, v2);
-        }
+            => !Equals(v1, v2);
     }
 
     public sealed partial class GameVersion : IComparable, IComparable<GameVersion>

Core/Versioning/GameVersionBound.cs

@@ -101,12 +101,7 @@ public override bool Equals(object obj)
         }
 
         public override int GetHashCode()
-        {
-            unchecked
-            {
-                return ((Value != null ? Value.GetHashCode() : 0)*397) ^ Inclusive.GetHashCode();
-            }
-        }
+            => (Value, Inclusive).GetHashCode();
 
         public static bool operator ==(GameVersionBound left, GameVersionBound right) => Equals(left, right);
         public static bool operator !=(GameVersionBound left, GameVersionBound right) => !Equals(left, right);

Core/Versioning/GameVersionRange.cs

@@ -170,12 +170,7 @@ public override bool Equals(object obj)
         }
 
         public override int GetHashCode()
-        {
-            unchecked
-            {
-                return ((Lower != null ? Lower.GetHashCode() : 0)*397) ^ (Upper != null ? Upper.GetHashCode() : 0);
-            }
-        }
+            => (Lower, Upper).GetHashCode();
 
         public static bool operator ==(GameVersionRange left, GameVersionRange right) => Equals(left, right);
         public static bool operator !=(GameVersionRange left, GameVersionRange right) => !Equals(left, right);

Core/Versioning/ModuleVersion.cs

@@ -103,32 +103,15 @@ public string ToString(bool hideEpoch, bool hideV)
     public partial class ModuleVersion : IEquatable<ModuleVersion>
     {
         public override bool Equals(object obj)
-        {
-            if (ReferenceEquals(this, obj))
-            {
-                return true;
-            }
-
-            return obj is ModuleVersion version && Equals(version);
-        }
+            => ReferenceEquals(this, obj)
+                || (obj is ModuleVersion version && Equals(version));
 
         public bool Equals(ModuleVersion other)
-        {
-            if (ReferenceEquals(this, other))
-            {
-                return true;
-            }
-
-            return CompareTo(other) == 0;
-        }
+            => ReferenceEquals(this, other)
+                || CompareTo(other) == 0;
 
         public override int GetHashCode()
-        {
-            unchecked
-            {
-                return (_epoch * 397) ^ _version.GetHashCode();
-            }
-        }
+            => (_epoch, _version).GetHashCode();
 
         /// <summary>
         /// Compares two <see cref="ModuleVersion"/> objects to determine if the first is equal to the second.
@@ -152,9 +135,7 @@ public override int GetHashCode()
         /// </list>
         /// </returns>
         public static bool operator ==(ModuleVersion left, ModuleVersion right)
-        {
-            return Equals(left, right);
-        }
+            => Equals(left, right);
 
         /// <summary>
         /// Compares two <see cref="ModuleVersion"/> objects to determine if the first is not equal to the second.
@@ -178,9 +159,7 @@ public override int GetHashCode()
         /// </list>
         /// </returns>
         public static bool operator !=(ModuleVersion left, ModuleVersion right)
-        {
-            return !Equals(left, right);
-        }
+            => !Equals(left, right);
     }
 
     public partial class ModuleVersion : IComparable<ModuleVersion>