Replace LINQ's custom Set with HashSet

src/libraries/System.Linq.Parallel/src/System.Linq.Parallel.csproj

@@ -18,6 +18,7 @@
  <Compile Include="System\Linq\Parallel\Enumerables\QueryAggregationOptions.cs" />
  <Compile Include="System\Linq\Parallel\Enumerables\RangeEnumerable.cs" />
  <Compile Include="System\Linq\Parallel\Enumerables\RepeatEnumerable.cs" />
+ <Compile Include="System\Linq\Parallel\JaggedArray.cs" />
  <Compile Include="System\Linq\Parallel\Merging\ArrayMergeHelper.cs" />
  <Compile Include="System\Linq\Parallel\Merging\AsynchronousChannelMergeEnumerator.cs" />
  <Compile Include="System\Linq\Parallel\Merging\DefaultMergeHelper.cs" />
@@ -123,7 +124,6 @@
  <Compile Include="System\Linq\Parallel\Scheduling\Scheduling.cs" />
  <Compile Include="System\Linq\Parallel\Scheduling\SpoolingTask.cs" />
  <Compile Include="System\Linq\Parallel\Scheduling\SpoolingTaskBase.cs" />
- <Compile Include="System\Linq\Parallel\Helpers.cs" />
  <Compile Include="System\Linq\Parallel\Utils\CancellableEnumerable.cs" />
  <Compile Include="System\Linq\Parallel\Utils\ExceptionAggregator.cs" />
  <Compile Include="System\Linq\Parallel\Utils\ExchangeUtilities.cs" />

src/libraries/System.Linq.Parallel/src/System/Linq/Parallel/JaggedArray.cs

@@ -0,0 +1,17 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+namespace System.Linq.Parallel
+{
+ internal class JaggedArray<TElement>
+ {
+ public static TElement[][] Allocate(int size1, int size2)
+ {
+ TElement[][] ret = new TElement[size1][];
+ for (int i = 0; i < size1; i++)
+ ret[i] = new TElement[size2];
+
+ return ret;
+ }
+ }
+}

src/libraries/System.Linq.Parallel/src/System/Linq/Parallel/QueryOperators/Binary/ExceptQueryOperator.cs

@@ -139,7 +139,7 @@ private class ExceptQueryOperatorEnumerator<TLeftKey> : QueryOperatorEnumerator<
  private readonly QueryOperatorEnumerator<Pair<TInputOutput, NoKeyMemoizationRequired>, TLeftKey> _leftSource; // Left data source.
  private readonly QueryOperatorEnumerator<Pair<TInputOutput, NoKeyMemoizationRequired>, int> _rightSource; // Right data source.
  private readonly IEqualityComparer<TInputOutput>? _comparer; // A comparer used for equality checks/hash-coding.
- private Set<TInputOutput>? _hashLookup; // The hash lookup, used to produce the distinct set.
+ private HashSet<TInputOutput>? _hashLookup; // The hash lookup, used to produce the distinct set.
  private readonly CancellationToken _cancellationToken;
  private Shared<int>? _outputLoopCount;
 
@@ -177,7 +177,7 @@ internal override bool MoveNext([MaybeNullWhen(false), AllowNull] ref TInputOutp
  {
  _outputLoopCount = new Shared<int>(0);
 
- _hashLookup = new Set<TInputOutput>(_comparer);
+ _hashLookup = new HashSet<TInputOutput>(_comparer);
 
  Pair<TInputOutput, NoKeyMemoizationRequired> rightElement = default(Pair<TInputOutput, NoKeyMemoizationRequired>);
  int rightKeyUnused = default(int);
@@ -265,7 +265,7 @@ internal override bool MoveNext([MaybeNullWhen(false), AllowNull] ref TInputOutp
  // Build the set out of the left data source, if we haven't already.
  if (_outputEnumerator == null)
  {
- Set<TInputOutput> rightLookup = new Set<TInputOutput>(_comparer);
+ HashSet<TInputOutput> rightLookup = new HashSet<TInputOutput>(_comparer);
 
  Pair<TInputOutput, NoKeyMemoizationRequired> rightElement = default(Pair<TInputOutput, NoKeyMemoizationRequired>);
  int rightKeyUnused = default(int);

src/libraries/System.Linq.Parallel/src/System/Linq/Parallel/QueryOperators/Binary/IntersectQueryOperator.cs

@@ -128,7 +128,7 @@ private class IntersectQueryOperatorEnumerator<TLeftKey> : QueryOperatorEnumerat
  private readonly QueryOperatorEnumerator<Pair<TInputOutput, NoKeyMemoizationRequired>, TLeftKey> _leftSource; // Left data source.
  private readonly QueryOperatorEnumerator<Pair<TInputOutput, NoKeyMemoizationRequired>, int> _rightSource; // Right data source.
  private readonly IEqualityComparer<TInputOutput>? _comparer; // Comparer to use for equality/hash-coding.
- private Set<TInputOutput>? _hashLookup; // The hash lookup, used to produce the intersection.
+ private HashSet<TInputOutput>? _hashLookup; // The hash lookup, used to produce the intersection.
  private readonly CancellationToken _cancellationToken;
  private Shared<int>? _outputLoopCount;
 
@@ -164,7 +164,7 @@ internal override bool MoveNext([MaybeNullWhen(false), AllowNull] ref TInputOutp
  if (_hashLookup == null)
  {
  _outputLoopCount = new Shared<int>(0);
- _hashLookup = new Set<TInputOutput>(_comparer);
+ _hashLookup = new HashSet<TInputOutput>(_comparer);
 
  Pair<TInputOutput, NoKeyMemoizationRequired> rightElement = default(Pair<TInputOutput, NoKeyMemoizationRequired>);
  int rightKeyUnused = default(int);

src/libraries/System.Linq.Parallel/src/System/Linq/Parallel/QueryOperators/Binary/UnionQueryOperator.cs

@@ -184,7 +184,7 @@ private class UnionQueryOperatorEnumerator<TLeftKey, TRightKey> : QueryOperatorE
  {
  private QueryOperatorEnumerator<Pair<TInputOutput, NoKeyMemoizationRequired>, TLeftKey>? _leftSource; // Left data source.
  private QueryOperatorEnumerator<Pair<TInputOutput, NoKeyMemoizationRequired>, TRightKey>? _rightSource; // Right data source.
- private Set<TInputOutput>? _hashLookup; // The hash lookup, used to produce the union.
+ private HashSet<TInputOutput>? _hashLookup; // The hash lookup, used to produce the union.
  private readonly CancellationToken _cancellationToken;
  private Shared<int>? _outputLoopCount;
  private readonly IEqualityComparer<TInputOutput>? _comparer;
@@ -216,7 +216,7 @@ internal override bool MoveNext([MaybeNullWhen(false), AllowNull] ref TInputOutp
  {
  if (_hashLookup == null)
  {
- _hashLookup = new Set<TInputOutput>(_comparer);
+ _hashLookup = new HashSet<TInputOutput>(_comparer);
  _outputLoopCount = new Shared<int>(0);
  }
 

src/libraries/System.Linq.Parallel/src/System/Linq/Parallel/QueryOperators/Unary/DistinctQueryOperator.cs

@@ -119,7 +119,7 @@ internal override bool LimitsParallelism
  private class DistinctQueryOperatorEnumerator<TKey> : QueryOperatorEnumerator<TInputOutput, int>
  {
  private readonly QueryOperatorEnumerator<Pair<TInputOutput, NoKeyMemoizationRequired>, TKey> _source; // The data source.
- private readonly Set<TInputOutput> _hashLookup; // The hash lookup, used to produce the distinct set.
+ private readonly HashSet<TInputOutput> _hashLookup; // The hash lookup, used to produce the distinct set.
  private readonly CancellationToken _cancellationToken;
  private Shared<int>? _outputLoopCount; // Allocated in MoveNext to avoid false sharing.
 
@@ -133,7 +133,7 @@ internal DistinctQueryOperatorEnumerator(
  {
  Debug.Assert(source != null);
  _source = source;
- _hashLookup = new Set<TInputOutput>(comparer);
+ _hashLookup = new HashSet<TInputOutput>(comparer);
  _cancellationToken = cancellationToken;
  }
 

src/libraries/System.Linq/src/System.Linq.csproj

@@ -80,7 +80,6 @@
  <Compile Include="System\Linq\Select.cs" />
  <Compile Include="System\Linq\SelectMany.cs" />
  <Compile Include="System\Linq\SequenceEqual.cs" />
- <Compile Include="System\Linq\Set.cs" />
  <Compile Include="System\Linq\Single.cs" />
  <Compile Include="System\Linq\SingleLinkedNode.cs" />
  <Compile Include="System\Linq\Skip.cs" />

src/libraries/System.Linq/src/System/Linq/Distinct.SpeedOpt.cs

@@ -9,18 +9,11 @@ public static partial class Enumerable
  {
  private sealed partial class DistinctIterator<TSource> : IIListProvider<TSource>
  {
- private Set<TSource> FillSet()
- {
- var set = new Set<TSource>(_comparer);
- set.UnionWith(_source);
- return set;
- }
+ public TSource[] ToArray() => Enumerable.ToArray(new HashSet<TSource>(_source, _comparer));
 
- public TSource[] ToArray() => FillSet().ToArray();
+ public List<TSource> ToList() => Enumerable.ToList(new HashSet<TSource>(_source, _comparer));
 
- public List<TSource> ToList() => FillSet().ToList();
-
- public int GetCount(bool onlyIfCheap) => onlyIfCheap ? -1 : FillSet().Count;
+ public int GetCount(bool onlyIfCheap) => onlyIfCheap ? -1 : new HashSet<TSource>(_source, _comparer).Count;
  }
  }
 }

src/libraries/System.Linq/src/System/Linq/Distinct.cs

@@ -28,7 +28,7 @@ private sealed partial class DistinctIterator<TSource> : Iterator<TSource>
  {
  private readonly IEnumerable<TSource> _source;
  private readonly IEqualityComparer<TSource>? _comparer;
- private Set<TSource>? _set;
+ private HashSet<TSource>? _set;
  private IEnumerator<TSource>? _enumerator;
 
  public DistinctIterator(IEnumerable<TSource> source, IEqualityComparer<TSource>? comparer)
@@ -53,7 +53,7 @@ public override bool MoveNext()
  }
 
  TSource element = _enumerator.Current;
- _set = new Set<TSource>(_comparer);
+ _set = new HashSet<TSource>(DefaultInternalSetCapacity, _comparer);
  _set.Add(element);
  _current = element;
  _state = 2;

src/libraries/System.Linq/src/System/Linq/Except.cs

@@ -39,8 +39,7 @@ public static IEnumerable<TSource> Except<TSource>(this IEnumerable<TSource> fir
 
  private static IEnumerable<TSource> ExceptIterator<TSource>(IEnumerable<TSource> first, IEnumerable<TSource> second, IEqualityComparer<TSource>? comparer)
  {
- Set<TSource> set = new Set<TSource>(comparer);
- set.UnionWith(second);
+ var set = new HashSet<TSource>(second, comparer);
 
  foreach (TSource element in first)
  {

src/libraries/System.Linq/src/System/Linq/Intersect.cs

@@ -39,8 +39,7 @@ public static IEnumerable<TSource> Intersect<TSource>(this IEnumerable<TSource>
 
  private static IEnumerable<TSource> IntersectIterator<TSource>(IEnumerable<TSource> first, IEnumerable<TSource> second, IEqualityComparer<TSource>? comparer)
  {
- Set<TSource> set = new Set<TSource>(comparer);
- set.UnionWith(second);
+ var set = new HashSet<TSource>(second, comparer);
 
  foreach (TSource element in first)
  {