From 656991e8a23a65cd41f3037a778679159f2aaeee Mon Sep 17 00:00:00 2001
From: Bouke Haarsma <bouke@haarsma.eu>
Date: Tue, 16 Jul 2024 09:24:25 +0200
Subject: [PATCH] Use HashCode from Microsoft.Bcl.HashCode

---
 Directory.Packages.props                               | 1 +
 Source/SuperLinq.Async/SuperLinq.Async.csproj          | 1 +
 Source/SuperLinq/KeyValuePairEqualityComparer.cs       | 4 ----
 Source/SuperLinq/SuperLinq.csproj                      | 1 +
 Source/SuperLinq/ValueTupleEqualityComparer.cs         | 4 ----
 Tests/SuperLinq.Test/ValueTupleEqualityComparerTest.cs | 4 ----
 6 files changed, 3 insertions(+), 12 deletions(-)

diff --git a/Directory.Packages.props b/Directory.Packages.props
index b2afa1ed..a785a008 100644
--- a/Directory.Packages.props
+++ b/Directory.Packages.props
@@ -20,6 +20,7 @@
 	<PackageVersion Include="System.Memory" Version="4.5.5" />
 	<PackageVersion Include="ThisAssembly.Resources" Version="1.4.3" />
 	<PackageVersion Include="xunit" Version="2.8.1" />
+    <PackageVersion Include="Microsoft.Bcl.HashCode" Version="1.1.1" />
   </ItemGroup>
 
   <ItemGroup Condition=" '$(TargetFramework)' != 'netcoreapp3.1' ">
diff --git a/Source/SuperLinq.Async/SuperLinq.Async.csproj b/Source/SuperLinq.Async/SuperLinq.Async.csproj
index ad4e44fd..37d92ad8 100644
--- a/Source/SuperLinq.Async/SuperLinq.Async.csproj
+++ b/Source/SuperLinq.Async/SuperLinq.Async.csproj
@@ -125,6 +125,7 @@
   </ItemGroup>
 
 	<ItemGroup Condition="$(TargetFramework) == 'netstandard2.0'">
+		<PackageReference Include="Microsoft.Bcl.HashCode" />
 		<PackageReference Include="System.Memory" PrivateAssets="All" />
 		<AssemblyAttribute Include="System.Runtime.CompilerServices.InternalsVisibleTo">
 			<_Parameter1>SuperLinq.Async.Test</_Parameter1>
diff --git a/Source/SuperLinq/KeyValuePairEqualityComparer.cs b/Source/SuperLinq/KeyValuePairEqualityComparer.cs
index ce598185..5f2cd97c 100644
--- a/Source/SuperLinq/KeyValuePairEqualityComparer.cs
+++ b/Source/SuperLinq/KeyValuePairEqualityComparer.cs
@@ -48,12 +48,8 @@ public bool Equals(KeyValuePair<TKey, TValue> x, KeyValuePair<TKey, TValue> y) =
 			&& _valueComparer.Equals(x.Value, y.Value);
 
 		public int GetHashCode(KeyValuePair<TKey, TValue> obj) =>
-#if NETCOREAPP
 			HashCode.Combine(
 				_keyComparer.GetHashCode(obj.Key!),
 				_valueComparer.GetHashCode(obj.Value!));
-#else
-			_keyComparer.GetHashCode(obj.Key) * 397 ^ _valueComparer.GetHashCode(obj.Value);
-#endif
 	}
 }
diff --git a/Source/SuperLinq/SuperLinq.csproj b/Source/SuperLinq/SuperLinq.csproj
index 98ce9be2..12bdf0a4 100644
--- a/Source/SuperLinq/SuperLinq.csproj
+++ b/Source/SuperLinq/SuperLinq.csproj
@@ -164,6 +164,7 @@
   </ItemGroup>
 
 	<ItemGroup Condition="$(TargetFramework) == 'netstandard2.0'">
+		<PackageReference Include="Microsoft.Bcl.HashCode" />
 		<PackageReference Include="System.Memory" PrivateAssets="All" />
 		<AssemblyAttribute Include="System.Runtime.CompilerServices.InternalsVisibleTo">
 			<_Parameter1>SuperLinq.Test</_Parameter1>
diff --git a/Source/SuperLinq/ValueTupleEqualityComparer.cs b/Source/SuperLinq/ValueTupleEqualityComparer.cs
index d55e1de4..e8f11e3d 100644
--- a/Source/SuperLinq/ValueTupleEqualityComparer.cs
+++ b/Source/SuperLinq/ValueTupleEqualityComparer.cs
@@ -87,12 +87,8 @@ public bool Equals(
 			&& _comparer2.Equals(x.Item2, y.Item2);
 
 		public int GetHashCode((T1, T2) obj) =>
-#if NETCOREAPP
 			HashCode.Combine(
 				_comparer1.GetHashCode(obj.Item1!),
 				_comparer2.GetHashCode(obj.Item2!));
-#else
-			_comparer1.GetHashCode(obj.Item1) * 397 ^ _comparer2.GetHashCode(obj.Item2);
-#endif
 	}
 }
diff --git a/Tests/SuperLinq.Test/ValueTupleEqualityComparerTest.cs b/Tests/SuperLinq.Test/ValueTupleEqualityComparerTest.cs
index 8946c252..23c6e862 100644
--- a/Tests/SuperLinq.Test/ValueTupleEqualityComparerTest.cs
+++ b/Tests/SuperLinq.Test/ValueTupleEqualityComparerTest.cs
@@ -79,11 +79,7 @@ public void ValueTupleEqualityComparerWithTwoTypeArgsShouldGetHashCode()
 		var comparer = ValueTupleEqualityComparer.Create<int, int>(comparer1: null, comparer2: null);
 		ValueTuple<int, int> first = new(1, 2);
 		var firstHashCode = comparer.GetHashCode(first);
-#if NETCOREAPP
 		var expectedHashCode = HashCode.Combine(1.GetHashCode(), 2.GetHashCode());
-#else
-		var expectedHashCode = 1.GetHashCode() * 397 ^ 2.GetHashCode();
-#endif
 		Assert.Equal(expectedHashCode, firstHashCode);
 	}
 }