From 6ba7183870b7791f40e541501c7d8b34c148d9a7 Mon Sep 17 00:00:00 2001
From: hrrrrustic <hrrrrustic@gmail.com>
Date: Sun, 7 May 2023 00:07:24 +0300
Subject: [PATCH 01/17] Implement hashset

---
 .../System.Collections/ref/System.Collections.cs          | 2 ++
 .../src/System/Collections/Generic/HashSet.cs             | 8 +++++---
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/src/libraries/System.Collections/ref/System.Collections.cs b/src/libraries/System.Collections/ref/System.Collections.cs
index c12b04c3a3cf07..64b4eb3ba5be1f 100644
--- a/src/libraries/System.Collections/ref/System.Collections.cs
+++ b/src/libraries/System.Collections/ref/System.Collections.cs
@@ -582,6 +582,7 @@ public HashSet(int capacity, System.Collections.Generic.IEqualityComparer<T>? co
         protected HashSet(System.Runtime.Serialization.SerializationInfo info, System.Runtime.Serialization.StreamingContext context) { }
         public System.Collections.Generic.IEqualityComparer<T> Comparer { get { throw null; } }
         public int Count { get { throw null; } }
+        public int Capacity { get { throw null; } }
         bool System.Collections.Generic.ICollection<T>.IsReadOnly { get { throw null; } }
         public bool Add(T item) { throw null; }
         public void Clear() { }
@@ -611,6 +612,7 @@ void System.Collections.Generic.ICollection<T>.Add(T item) { }
         System.Collections.Generic.IEnumerator<T> System.Collections.Generic.IEnumerable<T>.GetEnumerator() { throw null; }
         System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator() { throw null; }
         public void TrimExcess() { }
+        public void TrimExcess(int capacity) { }
         public bool TryGetValue(T equalValue, [System.Diagnostics.CodeAnalysis.MaybeNullWhenAttribute(false)] out T actualValue) { throw null; }
         public void UnionWith(System.Collections.Generic.IEnumerable<T> other) { }
         public partial struct Enumerator : System.Collections.Generic.IEnumerator<T>, System.Collections.IEnumerator, System.IDisposable
diff --git a/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/HashSet.cs b/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/HashSet.cs
index 668550bddf66b5..7bb47c1a701476 100644
--- a/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/HashSet.cs
+++ b/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/HashSet.cs
@@ -353,6 +353,8 @@ public bool Remove(T item)
         /// <summary>Gets the number of elements that are contained in the set.</summary>
         public int Count => _count - _freeCount;
 
+        public int Capacity => _count;
+
         bool ICollection<T>.IsReadOnly => false;
 
         #endregion
@@ -1005,10 +1007,10 @@ private void Resize(int newSize, bool forceNewHashCodes)
         /// Sets the capacity of a <see cref="HashSet{T}"/> object to the actual number of elements it contains,
         /// rounded up to a nearby, implementation-specific value.
         /// </summary>
-        public void TrimExcess()
-        {
-            int capacity = Count;
+        public void TrimExcess() => TrimExcess(Count);
 
+        public void TrimExcess(int capacity)
+        {
             int newSize = HashHelpers.GetPrime(capacity);
             Entry[]? oldEntries = _entries;
             int currentCapacity = oldEntries == null ? 0 : oldEntries.Length;

From 9dcfca968b53340d2f8eaa36bdca66de680c6ef0 Mon Sep 17 00:00:00 2001
From: hrrrrustic <hrrrrustic@gmail.com>
Date: Sun, 7 May 2023 00:07:47 +0300
Subject: [PATCH 02/17] Implement queue & stack & dictionary

---
 .../ref/System.Collections.cs                 |  5 ++++
 .../src/System/Collections/Generic/Stack.cs   | 23 ++++++++++++-------
 .../System/Collections/Generic/Dictionary.cs  |  2 ++
 .../src/System/Collections/Generic/Queue.cs   | 23 ++++++++++++-------
 4 files changed, 37 insertions(+), 16 deletions(-)

diff --git a/src/libraries/System.Collections/ref/System.Collections.cs b/src/libraries/System.Collections/ref/System.Collections.cs
index 64b4eb3ba5be1f..2fa8f622b611f6 100644
--- a/src/libraries/System.Collections/ref/System.Collections.cs
+++ b/src/libraries/System.Collections/ref/System.Collections.cs
@@ -379,6 +379,7 @@ public Stack() { }
         public Stack(System.Collections.Generic.IEnumerable<T> collection) { }
         public Stack(int capacity) { }
         public int Count { get { throw null; } }
+        public int Capacity { get { throw null; } }
         bool System.Collections.ICollection.IsSynchronized { get { throw null; } }
         object System.Collections.ICollection.SyncRoot { get { throw null; } }
         public void Clear() { }
@@ -394,6 +395,7 @@ void System.Collections.ICollection.CopyTo(System.Array array, int arrayIndex) {
         public int EnsureCapacity(int capacity) { throw null; }
         public T[] ToArray() { throw null; }
         public void TrimExcess() { }
+        public void TrimExcess(int capacity) { }
         public bool TryPeek([System.Diagnostics.CodeAnalysis.MaybeNullWhenAttribute(false)] out T result) { throw null; }
         public bool TryPop([System.Diagnostics.CodeAnalysis.MaybeNullWhenAttribute(false)] out T result) { throw null; }
         public partial struct Enumerator : System.Collections.Generic.IEnumerator<T>, System.Collections.IEnumerator, System.IDisposable
@@ -447,6 +449,7 @@ public Dictionary(int capacity, System.Collections.Generic.IEqualityComparer<TKe
         protected Dictionary(System.Runtime.Serialization.SerializationInfo info, System.Runtime.Serialization.StreamingContext context) { }
         public System.Collections.Generic.IEqualityComparer<TKey> Comparer { get { throw null; } }
         public int Count { get { throw null; } }
+        public int Capacity { get { throw null; } }
         public TValue this[TKey key] { get { throw null; } set { } }
         public System.Collections.Generic.Dictionary<TKey, TValue>.KeyCollection Keys { get { throw null; } }
         bool System.Collections.Generic.ICollection<System.Collections.Generic.KeyValuePair<TKey, TValue>>.IsReadOnly { get { throw null; } }
@@ -715,6 +718,7 @@ public Queue() { }
         public Queue(System.Collections.Generic.IEnumerable<T> collection) { }
         public Queue(int capacity) { }
         public int Count { get { throw null; } }
+        public int Capacity { get { throw null; } }
         bool System.Collections.ICollection.IsSynchronized { get { throw null; } }
         object System.Collections.ICollection.SyncRoot { get { throw null; } }
         public void Clear() { }
@@ -729,6 +733,7 @@ void System.Collections.ICollection.CopyTo(System.Array array, int index) { }
         System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator() { throw null; }
         public T[] ToArray() { throw null; }
         public void TrimExcess() { }
+        public void TrimExcess(int capacity) { }
         public int EnsureCapacity(int capacity) { throw null; }
         public bool TryDequeue([System.Diagnostics.CodeAnalysis.MaybeNullWhenAttribute(false)] out T result) { throw null; }
         public bool TryPeek([System.Diagnostics.CodeAnalysis.MaybeNullWhenAttribute(false)] out T result) { throw null; }
diff --git a/src/libraries/System.Collections/src/System/Collections/Generic/Stack.cs b/src/libraries/System.Collections/src/System/Collections/Generic/Stack.cs
index 2bc209c6a01e0b..19e057538304a0 100644
--- a/src/libraries/System.Collections/src/System/Collections/Generic/Stack.cs
+++ b/src/libraries/System.Collections/src/System/Collections/Generic/Stack.cs
@@ -54,15 +54,11 @@ public Stack(IEnumerable<T> collection)
             _array = EnumerableHelpers.ToArray(collection, out _size);
         }
 
-        public int Count
-        {
-            get { return _size; }
-        }
+        public int Count => _size;
 
-        bool ICollection.IsSynchronized
-        {
-            get { return false; }
-        }
+        public int Capacity => _array.Length;
+
+        bool ICollection.IsSynchronized => false;
 
         object ICollection.SyncRoot => this;
 
@@ -170,6 +166,17 @@ public void TrimExcess()
             }
         }
 
+        public void TrimExcess(int capacity)
+        {
+            ArgumentOutOfRangeException.ThrowIfNegativeOrZero(capacity);
+            ArgumentOutOfRangeException.ThrowIfLessThan(capacity, _size);
+
+            if (capacity == _size)
+                return;
+
+            Array.Resize(ref _array, capacity);
+        }
+
         // Returns the top object on the stack without removing it.  If the stack
         // is empty, Peek throws an InvalidOperationException.
         public T Peek()
diff --git a/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/Dictionary.cs b/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/Dictionary.cs
index 39770356157442..8c2c3504e75320 100644
--- a/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/Dictionary.cs
+++ b/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/Dictionary.cs
@@ -208,6 +208,8 @@ public IEqualityComparer<TKey> Comparer
 
         public int Count => _count - _freeCount;
 
+        public int Capacity => _count;
+
         public KeyCollection Keys => _keys ??= new KeyCollection(this);
 
         ICollection<TKey> IDictionary<TKey, TValue>.Keys => Keys;
diff --git a/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/Queue.cs b/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/Queue.cs
index 9d9ec66416736d..ed77bedb0208af 100644
--- a/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/Queue.cs
+++ b/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/Queue.cs
@@ -52,15 +52,11 @@ public Queue(IEnumerable<T> collection)
             if (_size != _array.Length) _tail = _size;
         }
 
-        public int Count
-        {
-            get { return _size; }
-        }
+        public int Count => _size;
 
-        bool ICollection.IsSynchronized
-        {
-            get { return false; }
-        }
+        public int Capacity => _array.Length;
+
+        bool ICollection.IsSynchronized => false;
 
         object ICollection.SyncRoot => this;
 
@@ -358,6 +354,17 @@ public void TrimExcess()
             }
         }
 
+        public void TrimExcess(int capacity)
+        {
+            ArgumentOutOfRangeException.ThrowIfNegative(capacity);
+            ArgumentOutOfRangeException.ThrowIfLessThan(capacity, _size);
+
+            if (capacity == _size)
+                return;
+
+            SetCapacity(capacity);
+        }
+
         /// <summary>
         /// Ensures that the capacity of this Queue is at least the specified <paramref name="capacity"/>.
         /// </summary>

From 3755185e125b182e0fe668cd7ff8394a9c6c58f6 Mon Sep 17 00:00:00 2001
From: hrrrrustic <hrrrrustic@gmail.com>
Date: Sun, 7 May 2023 00:27:31 +0300
Subject: [PATCH 03/17] Add doc comments

---
 .../src/System/Collections/Generic/Stack.cs               | 8 ++++++++
 .../src/System/Collections/Generic/Dictionary.cs          | 3 +++
 .../src/System/Collections/Generic/HashSet.cs             | 8 ++++++++
 .../src/System/Collections/Generic/Queue.cs               | 7 +++++++
 4 files changed, 26 insertions(+)

diff --git a/src/libraries/System.Collections/src/System/Collections/Generic/Stack.cs b/src/libraries/System.Collections/src/System/Collections/Generic/Stack.cs
index 19e057538304a0..30c2ad70dce6af 100644
--- a/src/libraries/System.Collections/src/System/Collections/Generic/Stack.cs
+++ b/src/libraries/System.Collections/src/System/Collections/Generic/Stack.cs
@@ -56,6 +56,10 @@ public Stack(IEnumerable<T> collection)
 
         public int Count => _size;
 
+
+        /// <summary>
+        /// Gets the total numbers of elements the internal data structure can hold without resizing.
+        /// </summary>
         public int Capacity => _array.Length;
 
         bool ICollection.IsSynchronized => false;
@@ -166,6 +170,10 @@ public void TrimExcess()
             }
         }
 
+        /// <summary>
+        /// Sets the capacity of a <see cref="Stack{T}"/> object to a specified number of entries.
+        /// </summary>
+        /// <param name="capacity">The new capacity.</param>
         public void TrimExcess(int capacity)
         {
             ArgumentOutOfRangeException.ThrowIfNegativeOrZero(capacity);
diff --git a/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/Dictionary.cs b/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/Dictionary.cs
index 8c2c3504e75320..ad02792c7476e6 100644
--- a/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/Dictionary.cs
+++ b/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/Dictionary.cs
@@ -208,6 +208,9 @@ public IEqualityComparer<TKey> Comparer
 
         public int Count => _count - _freeCount;
 
+        /// <summary>
+        /// Gets the total numbers of elements the internal data structure can hold without resizing.
+        /// </summary>
         public int Capacity => _count;
 
         public KeyCollection Keys => _keys ??= new KeyCollection(this);
diff --git a/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/HashSet.cs b/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/HashSet.cs
index 7bb47c1a701476..471e373b50340b 100644
--- a/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/HashSet.cs
+++ b/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/HashSet.cs
@@ -353,6 +353,9 @@ public bool Remove(T item)
         /// <summary>Gets the number of elements that are contained in the set.</summary>
         public int Count => _count - _freeCount;
 
+        /// <summary>
+        /// Gets the total numbers of elements the internal data structure can hold without resizing.
+        /// </summary>
         public int Capacity => _count;
 
         bool ICollection<T>.IsReadOnly => false;
@@ -1009,6 +1012,11 @@ private void Resize(int newSize, bool forceNewHashCodes)
         /// </summary>
         public void TrimExcess() => TrimExcess(Count);
 
+        /// <summary>
+        /// Sets the capacity of a <see cref="HashSet{T}"/> object to the specified number of entries,
+        /// rounded up to a nearby, implementation-specific value.
+        /// </summary>
+        /// <param name="capacity">The new capacity.</param>
         public void TrimExcess(int capacity)
         {
             int newSize = HashHelpers.GetPrime(capacity);
diff --git a/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/Queue.cs b/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/Queue.cs
index ed77bedb0208af..ad9b30d7a3cee4 100644
--- a/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/Queue.cs
+++ b/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/Queue.cs
@@ -54,6 +54,9 @@ public Queue(IEnumerable<T> collection)
 
         public int Count => _size;
 
+        /// <summary>
+        /// Gets the total numbers of elements the internal data structure can hold without resizing.
+        /// </summary>
         public int Capacity => _array.Length;
 
         bool ICollection.IsSynchronized => false;
@@ -354,6 +357,10 @@ public void TrimExcess()
             }
         }
 
+        /// <summary>
+        /// Sets the capacity of a <see cref="Queue{T}"/> object to the specified number of entries.
+        /// </summary>
+        /// <param name="capacity">The new capacity.</param>
         public void TrimExcess(int capacity)
         {
             ArgumentOutOfRangeException.ThrowIfNegative(capacity);

From 5194c0bc6e3298d237758b5c3b14736da8b486e8 Mon Sep 17 00:00:00 2001
From: hrrrrustic <hrrrrustic@gmail.com>
Date: Sun, 7 May 2023 01:21:02 +0300
Subject: [PATCH 04/17] Add some tests

---
 .../Dictionary/Dictionary.Generic.Tests.cs    |  9 ++++++
 .../Generic/HashSet/HashSet.Generic.Tests.cs  | 29 +++++++++++++++++++
 .../Generic/Queue/Queue.Generic.Tests.cs      | 29 +++++++++++++++++++
 .../Generic/Stack/Stack.Generic.Tests.cs      | 29 +++++++++++++++++++
 4 files changed, 96 insertions(+)

diff --git a/src/libraries/System.Collections/tests/Generic/Dictionary/Dictionary.Generic.Tests.cs b/src/libraries/System.Collections/tests/Generic/Dictionary/Dictionary.Generic.Tests.cs
index fa12ef55d6c540..ed8c1860b1dc9c 100644
--- a/src/libraries/System.Collections/tests/Generic/Dictionary/Dictionary.Generic.Tests.cs
+++ b/src/libraries/System.Collections/tests/Generic/Dictionary/Dictionary.Generic.Tests.cs
@@ -83,6 +83,15 @@ public void Dictionary_Generic_Constructor_int_IEqualityComparer(int count)
             Assert.Equal(comparer, dictionary.Comparer);
         }
 
+        [Theory]
+        [InlineData(1)]
+        [InlineData(100)]
+        public void Stack_CreateWithCapacity_EqualsCapacityProperty(int capacity)
+        {
+            Dictionary<TKey, TValue> dict = new Dictionary<TKey, TValue>(capacity);
+            Assert.Equal(capacity, dict.Capacity);
+        }
+
         #endregion
 
         #region ContainsValue
diff --git a/src/libraries/System.Collections/tests/Generic/HashSet/HashSet.Generic.Tests.cs b/src/libraries/System.Collections/tests/Generic/HashSet/HashSet.Generic.Tests.cs
index afbcad3c357cf6..016a9ad4ed0751 100644
--- a/src/libraries/System.Collections/tests/Generic/HashSet/HashSet.Generic.Tests.cs
+++ b/src/libraries/System.Collections/tests/Generic/HashSet/HashSet.Generic.Tests.cs
@@ -126,6 +126,15 @@ public void HashSet_Generic_Constructor_IEnumerable_IEqualityComparer(Enumerable
             Assert.True(set.SetEquals(enumerable));
         }
 
+        [Theory]
+        [InlineData(1)]
+        [InlineData(100)]
+        public void Stack_CreateWithCapacity_EqualsCapacityProperty(int capacity)
+        {
+            var hashSet = new HashSet<T>(capacity);
+            Assert.Equal(capacity, hashSet.Capacity);
+        }
+
         #endregion
 
         #region RemoveWhere
@@ -175,6 +184,26 @@ public void HashSet_Generic_RemoveWhere_NullMatchPredicate(int setLength)
 
         #region TrimExcess
 
+        [Theory]
+        [InlineData(1, -1)]
+        [InlineData(2, 1)]
+        public void HashSet_TrimAccessWithInvalidArg_ThrowOutOfRange(int size, int newCapacity)
+        {
+            HashSet<T> hashSet = (HashSet<T>)GenericISetFactory(size);
+
+            AssertExtensions.Throws<ArgumentOutOfRangeException>(() => hashSet.TrimExcess(newCapacity));
+        }
+
+        public void HashSet_TrimAccessCurrentCapacity_DoesNothing()
+        {
+            var hashSet = new HashSet<T>(10);
+            var initialCapacity = hashSet.Capacity;
+            hashSet.TrimExcess(initialCapacity);
+            var afterTrimCapacity = hashSet.Capacity;
+
+            Assert.Equal(initialCapacity, afterTrimCapacity);
+        }
+
         [Theory]
         [MemberData(nameof(ValidCollectionSizes))]
         public void HashSet_Generic_TrimExcess_OnValidSetThatHasntBeenRemovedFrom(int setLength)
diff --git a/src/libraries/System.Collections/tests/Generic/Queue/Queue.Generic.Tests.cs b/src/libraries/System.Collections/tests/Generic/Queue/Queue.Generic.Tests.cs
index 3fd069023ca253..0810ead9a984bf 100644
--- a/src/libraries/System.Collections/tests/Generic/Queue/Queue.Generic.Tests.cs
+++ b/src/libraries/System.Collections/tests/Generic/Queue/Queue.Generic.Tests.cs
@@ -97,6 +97,15 @@ public void Queue_Generic_Constructor_int_Negative_ThrowsArgumentOutOfRangeExcep
             AssertExtensions.Throws<ArgumentOutOfRangeException>("capacity", () => new Queue<T>(int.MinValue));
         }
 
+        [Theory]
+        [InlineData(1)]
+        [InlineData(100)]
+        public void Queue_CreateWithCapacity_EqualsCapacityProperty(int capacity)
+        {
+            var queue = new Queue<T>(capacity);
+            Assert.Equal(capacity, queue.Capacity);
+        }
+
         #endregion
 
         #region Dequeue
@@ -203,6 +212,26 @@ public void Queue_Generic_Peek_OnEmptyQueue_ThrowsInvalidOperationException()
 
         #region TrimExcess
 
+        [Theory]
+        [InlineData(1, -1)]
+        [InlineData(2, 1)]
+        public void Queue_TrimAccessWithInvalidArg_ThrowOutOfRange(int size, int newCapacity)
+        {
+            Queue<T> queue = GenericQueueFactory(size);
+
+            AssertExtensions.Throws<ArgumentOutOfRangeException>(() => queue.TrimExcess(newCapacity));
+        }
+
+        public void Queue_TrimAccessCurrentCapacity_DoesNothing()
+        {
+            var queue = new Queue<T>(10);
+            var initialCapacity = queue.Capacity;
+            queue.TrimExcess(initialCapacity);
+            var afterTrimCapacity = queue.Capacity;
+
+            Assert.Equal(initialCapacity, afterTrimCapacity);
+        }
+
         [Theory]
         [MemberData(nameof(ValidCollectionSizes))]
         public void Queue_Generic_TrimExcess_OnValidQueueThatHasntBeenRemovedFrom(int count)
diff --git a/src/libraries/System.Collections/tests/Generic/Stack/Stack.Generic.Tests.cs b/src/libraries/System.Collections/tests/Generic/Stack/Stack.Generic.Tests.cs
index 4c5c5a49d243e1..9babd0b3beae74 100644
--- a/src/libraries/System.Collections/tests/Generic/Stack/Stack.Generic.Tests.cs
+++ b/src/libraries/System.Collections/tests/Generic/Stack/Stack.Generic.Tests.cs
@@ -108,6 +108,15 @@ public void Stack_Generic_Constructor_int_Negative_ThrowsArgumentOutOfRangeExcep
             AssertExtensions.Throws<ArgumentOutOfRangeException>("capacity", () => new Stack<T>(int.MinValue));
         }
 
+        [Theory]
+        [InlineData(1)]
+        [InlineData(100)]
+        public void Stack_CreateWithCapacity_EqualsCapacityProperty(int capacity)
+        {
+            var stack = new Stack<T>(capacity);
+            Assert.Equal(capacity, stack.Capacity);
+        }
+
         #endregion
 
         #region Pop
@@ -167,6 +176,26 @@ public void Stack_Generic_Peek_OnEmptyStack_ThrowsInvalidOperationException()
 
         #region TrimExcess
 
+        [Theory]
+        [InlineData(1, -1)]
+        [InlineData(2, 1)]
+        public void Stack_TrimAccessWithInvalidArg_ThrowOutOfRange(int size, int newCapacity)
+        {
+            Stack<T> stack = GenericStackFactory(size);
+
+            AssertExtensions.Throws<ArgumentOutOfRangeException>(() => stack.TrimExcess(newCapacity));
+        }
+
+        public void Stack_TrimAccessCurrentCapacity_DoesNothing()
+        {
+            var stack = new Stack<T>(10);
+            var initialCapacity = stack.Capacity;
+            stack.TrimExcess(initialCapacity);
+            var afterTrimCapacity = stack.Capacity;
+
+            Assert.Equal(initialCapacity, afterTrimCapacity);
+        }
+
         [Theory]
         [MemberData(nameof(ValidCollectionSizes))]
         public void Stack_Generic_TrimExcess_OnValidStackThatHasntBeenRemovedFrom(int count)

From 66c488b8d22196810174aaf1333033ca8b246730 Mon Sep 17 00:00:00 2001
From: hrrrrustic <hrrrrustic@gmail.com>
Date: Sun, 7 May 2023 01:25:41 +0300
Subject: [PATCH 05/17] Update implementation

---
 .../src/System/Collections/Generic/Stack.cs          |  2 +-
 .../src/System/Collections/Generic/HashSet.cs        | 12 +++++++++++-
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/src/libraries/System.Collections/src/System/Collections/Generic/Stack.cs b/src/libraries/System.Collections/src/System/Collections/Generic/Stack.cs
index 30c2ad70dce6af..25a98c5ac1d2ec 100644
--- a/src/libraries/System.Collections/src/System/Collections/Generic/Stack.cs
+++ b/src/libraries/System.Collections/src/System/Collections/Generic/Stack.cs
@@ -176,7 +176,7 @@ public void TrimExcess()
         /// <param name="capacity">The new capacity.</param>
         public void TrimExcess(int capacity)
         {
-            ArgumentOutOfRangeException.ThrowIfNegativeOrZero(capacity);
+            ArgumentOutOfRangeException.ThrowIfNegative(capacity);
             ArgumentOutOfRangeException.ThrowIfLessThan(capacity, _size);
 
             if (capacity == _size)
diff --git a/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/HashSet.cs b/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/HashSet.cs
index 471e373b50340b..abffedd141288d 100644
--- a/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/HashSet.cs
+++ b/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/HashSet.cs
@@ -1010,7 +1010,7 @@ private void Resize(int newSize, bool forceNewHashCodes)
         /// Sets the capacity of a <see cref="HashSet{T}"/> object to the actual number of elements it contains,
         /// rounded up to a nearby, implementation-specific value.
         /// </summary>
-        public void TrimExcess() => TrimExcess(Count);
+        public void TrimExcess() => SetCapacity(Count);
 
         /// <summary>
         /// Sets the capacity of a <see cref="HashSet{T}"/> object to the specified number of entries,
@@ -1018,6 +1018,16 @@ private void Resize(int newSize, bool forceNewHashCodes)
         /// </summary>
         /// <param name="capacity">The new capacity.</param>
         public void TrimExcess(int capacity)
+        {
+            ArgumentOutOfRangeException.ThrowIfNegative(capacity);
+            ArgumentOutOfRangeException.ThrowIfLessThan(capacity, _size);
+
+            if (capacity == _size)
+                return;
+
+            SetCapacity(capacity);
+        }
+        private void SetCapacity(int capacity)
         {
             int newSize = HashHelpers.GetPrime(capacity);
             Entry[]? oldEntries = _entries;

From 99404a47bc670d3901738d3d22142efb82faeb3b Mon Sep 17 00:00:00 2001
From: hrrrrustic <hrrrrustic@gmail.com>
Date: Sun, 7 May 2023 01:39:21 +0300
Subject: [PATCH 06/17] Update dict and hashset Capacity

---
 .../src/System/Collections/Generic/Dictionary.cs           | 2 +-
 .../src/System/Collections/Generic/HashSet.cs              | 7 +------
 2 files changed, 2 insertions(+), 7 deletions(-)

diff --git a/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/Dictionary.cs b/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/Dictionary.cs
index ad02792c7476e6..57e7ae04470468 100644
--- a/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/Dictionary.cs
+++ b/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/Dictionary.cs
@@ -211,7 +211,7 @@ public IEqualityComparer<TKey> Comparer
         /// <summary>
         /// Gets the total numbers of elements the internal data structure can hold without resizing.
         /// </summary>
-        public int Capacity => _count;
+        public int Capacity => _entries?.Length ?? 0;
 
         public KeyCollection Keys => _keys ??= new KeyCollection(this);
 
diff --git a/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/HashSet.cs b/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/HashSet.cs
index abffedd141288d..ed456fb9c41b83 100644
--- a/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/HashSet.cs
+++ b/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/HashSet.cs
@@ -356,7 +356,7 @@ public bool Remove(T item)
         /// <summary>
         /// Gets the total numbers of elements the internal data structure can hold without resizing.
         /// </summary>
-        public int Capacity => _count;
+        public int Capacity => _entries?.Length ?? 0;
 
         bool ICollection<T>.IsReadOnly => false;
 
@@ -1012,11 +1012,6 @@ private void Resize(int newSize, bool forceNewHashCodes)
         /// </summary>
         public void TrimExcess() => SetCapacity(Count);
 
-        /// <summary>
-        /// Sets the capacity of a <see cref="HashSet{T}"/> object to the specified number of entries,
-        /// rounded up to a nearby, implementation-specific value.
-        /// </summary>
-        /// <param name="capacity">The new capacity.</param>
         public void TrimExcess(int capacity)
         {
             ArgumentOutOfRangeException.ThrowIfNegative(capacity);

From 1c1d3c9cab28a6c9ebdc35f0cd6e59835307a2a5 Mon Sep 17 00:00:00 2001
From: hrrrrustic <hrrrrustic@gmail.com>
Date: Sun, 7 May 2023 02:20:41 +0300
Subject: [PATCH 07/17] size -> count

---
 .../src/System/Collections/Generic/HashSet.cs                 | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/HashSet.cs b/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/HashSet.cs
index ed456fb9c41b83..7d0cda6a6a0bdc 100644
--- a/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/HashSet.cs
+++ b/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/HashSet.cs
@@ -1015,9 +1015,9 @@ private void Resize(int newSize, bool forceNewHashCodes)
         public void TrimExcess(int capacity)
         {
             ArgumentOutOfRangeException.ThrowIfNegative(capacity);
-            ArgumentOutOfRangeException.ThrowIfLessThan(capacity, _size);
+            ArgumentOutOfRangeException.ThrowIfLessThan(capacity, _count);
 
-            if (capacity == _size)
+            if (capacity == _count)
                 return;
 
             SetCapacity(capacity);

From c1f68373ac53a8296c100dc934bbf841bf1c1235 Mon Sep 17 00:00:00 2001
From: hrrrrustic <hrrrrustic@gmail.com>
Date: Sun, 7 May 2023 03:15:23 +0300
Subject: [PATCH 08/17] Fix test names

---
 .../tests/Generic/Dictionary/Dictionary.Generic.Tests.cs        | 2 +-
 .../tests/Generic/HashSet/HashSet.Generic.Tests.cs              | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/libraries/System.Collections/tests/Generic/Dictionary/Dictionary.Generic.Tests.cs b/src/libraries/System.Collections/tests/Generic/Dictionary/Dictionary.Generic.Tests.cs
index ed8c1860b1dc9c..17cdaeb84c4555 100644
--- a/src/libraries/System.Collections/tests/Generic/Dictionary/Dictionary.Generic.Tests.cs
+++ b/src/libraries/System.Collections/tests/Generic/Dictionary/Dictionary.Generic.Tests.cs
@@ -86,7 +86,7 @@ public void Dictionary_Generic_Constructor_int_IEqualityComparer(int count)
         [Theory]
         [InlineData(1)]
         [InlineData(100)]
-        public void Stack_CreateWithCapacity_EqualsCapacityProperty(int capacity)
+        public void Dictionary_CreateWithCapacity_EqualsCapacityProperty(int capacity)
         {
             Dictionary<TKey, TValue> dict = new Dictionary<TKey, TValue>(capacity);
             Assert.Equal(capacity, dict.Capacity);
diff --git a/src/libraries/System.Collections/tests/Generic/HashSet/HashSet.Generic.Tests.cs b/src/libraries/System.Collections/tests/Generic/HashSet/HashSet.Generic.Tests.cs
index 016a9ad4ed0751..1f7611e477985c 100644
--- a/src/libraries/System.Collections/tests/Generic/HashSet/HashSet.Generic.Tests.cs
+++ b/src/libraries/System.Collections/tests/Generic/HashSet/HashSet.Generic.Tests.cs
@@ -129,7 +129,7 @@ public void HashSet_Generic_Constructor_IEnumerable_IEqualityComparer(Enumerable
         [Theory]
         [InlineData(1)]
         [InlineData(100)]
-        public void Stack_CreateWithCapacity_EqualsCapacityProperty(int capacity)
+        public void HashSet_CreateWithCapacity_EqualsCapacityProperty(int capacity)
         {
             var hashSet = new HashSet<T>(capacity);
             Assert.Equal(capacity, hashSet.Capacity);

From fd3eacd4e9f9c1751e7af6b776c93406a6925398 Mon Sep 17 00:00:00 2001
From: hrrrrustic <hrrrrustic@gmail.com>
Date: Mon, 31 Jul 2023 20:25:47 +0300
Subject: [PATCH 09/17] Update implementation

---
 .../src/System/Collections/Generic/Stack.cs          |  5 +++--
 .../src/System/Collections/Generic/Dictionary.cs     |  1 +
 .../src/System/Collections/Generic/HashSet.cs        | 12 +++++++++---
 .../src/System/Collections/Generic/Queue.cs          |  5 +++--
 4 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/src/libraries/System.Collections/src/System/Collections/Generic/Stack.cs b/src/libraries/System.Collections/src/System/Collections/Generic/Stack.cs
index 25a98c5ac1d2ec..63d37ba0b186c4 100644
--- a/src/libraries/System.Collections/src/System/Collections/Generic/Stack.cs
+++ b/src/libraries/System.Collections/src/System/Collections/Generic/Stack.cs
@@ -174,12 +174,13 @@ public void TrimExcess()
         /// Sets the capacity of a <see cref="Stack{T}"/> object to a specified number of entries.
         /// </summary>
         /// <param name="capacity">The new capacity.</param>
+        /// <exception cref="ArgumentOutOfRangeException">Passed capacity is lower than 0 or entries count.</exception>
         public void TrimExcess(int capacity)
         {
             ArgumentOutOfRangeException.ThrowIfNegative(capacity);
-            ArgumentOutOfRangeException.ThrowIfLessThan(capacity, _size);
+            ArgumentOutOfRangeException.ThrowIfLessThan(capacity, _array.Length);
 
-            if (capacity == _size)
+            if (capacity == _array.Length)
                 return;
 
             Array.Resize(ref _array, capacity);
diff --git a/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/Dictionary.cs b/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/Dictionary.cs
index 57e7ae04470468..6007efe778ce21 100644
--- a/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/Dictionary.cs
+++ b/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/Dictionary.cs
@@ -1185,6 +1185,7 @@ public int EnsureCapacity(int capacity)
         /// This method can be used to minimize the memory overhead
         /// once it is known that no new elements will be added.
         /// </remarks>
+        /// <exception cref="ArgumentOutOfRangeException">Passed capacity is lower than entries count.</exception>
         public void TrimExcess(int capacity)
         {
             if (capacity < Count)
diff --git a/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/HashSet.cs b/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/HashSet.cs
index 7d0cda6a6a0bdc..e8d974423d2217 100644
--- a/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/HashSet.cs
+++ b/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/HashSet.cs
@@ -1012,16 +1012,22 @@ private void Resize(int newSize, bool forceNewHashCodes)
         /// </summary>
         public void TrimExcess() => SetCapacity(Count);
 
+        /// <summary>
+        /// Sets the capacity of a <see cref="HashSet{T}"/> object to the specified number of entries.
+        /// </summary>
+        /// <param name="capacity">The new capacity.</param>
+        /// <exception cref="ArgumentOutOfRangeException">Passed capacity is lower than entries count.</exception>
         public void TrimExcess(int capacity)
         {
-            ArgumentOutOfRangeException.ThrowIfNegative(capacity);
-            ArgumentOutOfRangeException.ThrowIfLessThan(capacity, _count);
+            var currentCount = Count;
+            ArgumentOutOfRangeException.ThrowIfLessThan(capacity, currentCount);
 
-            if (capacity == _count)
+            if (capacity == currentCount)
                 return;
 
             SetCapacity(capacity);
         }
+
         private void SetCapacity(int capacity)
         {
             int newSize = HashHelpers.GetPrime(capacity);
diff --git a/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/Queue.cs b/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/Queue.cs
index ad9b30d7a3cee4..144ad3af777b2d 100644
--- a/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/Queue.cs
+++ b/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/Queue.cs
@@ -361,12 +361,13 @@ public void TrimExcess()
         /// Sets the capacity of a <see cref="Queue{T}"/> object to the specified number of entries.
         /// </summary>
         /// <param name="capacity">The new capacity.</param>
+        /// <exception cref="ArgumentOutOfRangeException">Passed capacity is lower than entries count.</exception>
         public void TrimExcess(int capacity)
         {
             ArgumentOutOfRangeException.ThrowIfNegative(capacity);
-            ArgumentOutOfRangeException.ThrowIfLessThan(capacity, _size);
+            ArgumentOutOfRangeException.ThrowIfLessThan(capacity, _array.Length);
 
-            if (capacity == _size)
+            if (capacity == _array.Length)
                 return;
 
             SetCapacity(capacity);

From 85a2ecc4fb74ecf0efacb68d555bb34901eb28c7 Mon Sep 17 00:00:00 2001
From: hrrrrustic <hrrrrustic@gmail.com>
Date: Mon, 31 Jul 2023 23:15:20 +0300
Subject: [PATCH 10/17] Update tests

---
 .../Dictionary/Dictionary.Generic.Tests.cs    | 23 +++++++++++-
 .../Generic/HashSet/HashSet.Generic.Tests.cs  | 37 ++++++++++++++-----
 .../Generic/Queue/Queue.Generic.Tests.cs      | 28 ++++++++++----
 .../Generic/Stack/Stack.Generic.Tests.cs      | 24 +++++++++---
 4 files changed, 88 insertions(+), 24 deletions(-)

diff --git a/src/libraries/System.Collections/tests/Generic/Dictionary/Dictionary.Generic.Tests.cs b/src/libraries/System.Collections/tests/Generic/Dictionary/Dictionary.Generic.Tests.cs
index 17cdaeb84c4555..aa6133538895d4 100644
--- a/src/libraries/System.Collections/tests/Generic/Dictionary/Dictionary.Generic.Tests.cs
+++ b/src/libraries/System.Collections/tests/Generic/Dictionary/Dictionary.Generic.Tests.cs
@@ -86,14 +86,33 @@ public void Dictionary_Generic_Constructor_int_IEqualityComparer(int count)
         [Theory]
         [InlineData(1)]
         [InlineData(100)]
-        public void Dictionary_CreateWithCapacity_EqualsCapacityProperty(int capacity)
+        public void Dictionary_CreateWithCapacity_CapacityAtLeastPassedValue(int capacity)
         {
             Dictionary<TKey, TValue> dict = new Dictionary<TKey, TValue>(capacity);
-            Assert.Equal(capacity, dict.Capacity);
+            Assert.True(capacity <= dict.Capacity);
         }
 
         #endregion
 
+        #region Properties
+
+        public void DictResized_CapacityChanged()
+        {
+            var dict = (Dictionary<TKey, TValue>)GenericIDictionaryFactory(1);
+            int initialCapacity = dict.Capacity;
+
+            int seed = 85877;
+            for (int i = 0; i < dict.Capacity; i++)
+            {
+                dict.Add(CreateTKey(seed++), CreateTValue(seed++));
+            }
+
+            int afterCapacity = dict.Capacity;
+
+            Assert.True(afterCapacity > initialCapacity);
+        }
+
+        #endregion
         #region ContainsValue
 
         [Theory]
diff --git a/src/libraries/System.Collections/tests/Generic/HashSet/HashSet.Generic.Tests.cs b/src/libraries/System.Collections/tests/Generic/HashSet/HashSet.Generic.Tests.cs
index 1f7611e477985c..19b2e3f000bba2 100644
--- a/src/libraries/System.Collections/tests/Generic/HashSet/HashSet.Generic.Tests.cs
+++ b/src/libraries/System.Collections/tests/Generic/HashSet/HashSet.Generic.Tests.cs
@@ -129,10 +129,31 @@ public void HashSet_Generic_Constructor_IEnumerable_IEqualityComparer(Enumerable
         [Theory]
         [InlineData(1)]
         [InlineData(100)]
-        public void HashSet_CreateWithCapacity_EqualsCapacityProperty(int capacity)
+        public void HashSet_CreateWithCapacity_CapacityAtLeastPassedValue(int capacity)
         {
             var hashSet = new HashSet<T>(capacity);
-            Assert.Equal(capacity, hashSet.Capacity);
+            Assert.True(capacity <= hashSet.Capacity);
+        }
+
+        #endregion
+
+        #region Properties
+
+        [Fact]
+        public void HashSetResized_CapacityChanged()
+        {
+            var hashSet = (HashSet<T>)GenericISetFactory(10);
+            int initialCapacity = hashSet.Capacity;
+
+            int seed = 85877;
+            for (int i = 0; i < hashSet.Capacity; i++)
+            {
+                hashSet.Add(CreateT(seed++));
+            }
+
+            int afterCapacity = hashSet.Capacity;
+
+            Assert.True(afterCapacity > initialCapacity);
         }
 
         #endregion
@@ -194,14 +215,12 @@ public void HashSet_TrimAccessWithInvalidArg_ThrowOutOfRange(int size, int newCa
             AssertExtensions.Throws<ArgumentOutOfRangeException>(() => hashSet.TrimExcess(newCapacity));
         }
 
-        public void HashSet_TrimAccessCurrentCapacity_DoesNothing()
+        [Fact]
+        public void TrimExcess_Generic_LargeInitialCapacity_TrimReducesSize()
         {
-            var hashSet = new HashSet<T>(10);
-            var initialCapacity = hashSet.Capacity;
-            hashSet.TrimExcess(initialCapacity);
-            var afterTrimCapacity = hashSet.Capacity;
-
-            Assert.Equal(initialCapacity, afterTrimCapacity);
+            var dictionary = new HashSet<T>(20);
+            dictionary.TrimExcess(7);
+            Assert.Equal(7, dictionary.EnsureCapacity(0));
         }
 
         [Theory]
diff --git a/src/libraries/System.Collections/tests/Generic/Queue/Queue.Generic.Tests.cs b/src/libraries/System.Collections/tests/Generic/Queue/Queue.Generic.Tests.cs
index 0810ead9a984bf..dc857cb5867eac 100644
--- a/src/libraries/System.Collections/tests/Generic/Queue/Queue.Generic.Tests.cs
+++ b/src/libraries/System.Collections/tests/Generic/Queue/Queue.Generic.Tests.cs
@@ -222,14 +222,16 @@ public void Queue_TrimAccessWithInvalidArg_ThrowOutOfRange(int size, int newCapa
             AssertExtensions.Throws<ArgumentOutOfRangeException>(() => queue.TrimExcess(newCapacity));
         }
 
-        public void Queue_TrimAccessCurrentCapacity_DoesNothing()
+        [Fact]
+        public void Queue_TrimAccessCurrentCount_DoesNothing()
         {
-            var queue = new Queue<T>(10);
-            var initialCapacity = queue.Capacity;
-            queue.TrimExcess(initialCapacity);
-            var afterTrimCapacity = queue.Capacity;
-
-            Assert.Equal(initialCapacity, afterTrimCapacity);
+            var queue = new Queue<T>();
+            queue.Enqueue(CreateT(85877));
+            queue.TrimExcess(queue.Count);
+            int capacity = queue.Capacity;
+            queue.TrimExcess(queue.Count);
+            int capacityAgain = queue.Capacity;
+            Assert.Equal(capacity, capacityAgain);
         }
 
         [Theory]
@@ -495,5 +497,17 @@ public void Queue_Generic_EnsureCapacity_RequestingLargerCapacity_DoesNotImpactQ
                 Assert.Equal(copiedList[i], queue.Dequeue());
             }
         }
+
+        [Fact]
+        public void QueueResized_CapacityUpdates()
+        {
+            var queue = GenericQueueFactory(1);
+
+            int initialCapacity = queue.Capacity;
+
+            queue.Enqueue(CreateT(85877));
+
+            Assert.True(initialCapacity < queue.Capacity);
+        }
     }
 }
diff --git a/src/libraries/System.Collections/tests/Generic/Stack/Stack.Generic.Tests.cs b/src/libraries/System.Collections/tests/Generic/Stack/Stack.Generic.Tests.cs
index 9babd0b3beae74..a3e04713f1d6aa 100644
--- a/src/libraries/System.Collections/tests/Generic/Stack/Stack.Generic.Tests.cs
+++ b/src/libraries/System.Collections/tests/Generic/Stack/Stack.Generic.Tests.cs
@@ -186,14 +186,15 @@ public void Stack_TrimAccessWithInvalidArg_ThrowOutOfRange(int size, int newCapa
             AssertExtensions.Throws<ArgumentOutOfRangeException>(() => stack.TrimExcess(newCapacity));
         }
 
-        public void Stack_TrimAccessCurrentCapacity_DoesNothing()
+        [Fact]
+        public void Stack_TrimAccessCurrentCount_DoesNothing()
         {
-            var stack = new Stack<T>(10);
-            var initialCapacity = stack.Capacity;
-            stack.TrimExcess(initialCapacity);
-            var afterTrimCapacity = stack.Capacity;
+            var stack = GenericStackFactory(10);
+            stack.TrimExcess(stack.Count);
+            int capacity = stack.Capacity;
+            stack.TrimExcess(stack.Count);
 
-            Assert.Equal(initialCapacity, afterTrimCapacity);
+            Assert.Equal(capacity, stack.Capacity);
         }
 
         [Theory]
@@ -424,5 +425,16 @@ public void Stack_Generic_EnsureCapacity_RequestingLargerCapacity_DoesNotImpactS
                 Assert.Equal(copiedList[i], stack.Pop());
             }
         }
+
+        [Fact]
+        public void StackResized_CapacityUpdates()
+        {
+            Stack<T> stack = GenericStackFactory(10);
+            int initialCapacity = stack.Capacity;
+
+            stack.Push(CreateT(85877));
+
+            Assert.True(initialCapacity < stack.Capacity);
+        }
     }
 }

From c81d144b64e5c7181805402e1d290264efb2390c Mon Sep 17 00:00:00 2001
From: hrrrrustic <hrrrrustic@gmail.com>
Date: Fri, 4 Aug 2023 01:18:28 +0300
Subject: [PATCH 11/17] Remove loop to try avoid oom

---
 .../tests/Generic/HashSet/HashSet.Generic.Tests.cs         | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/src/libraries/System.Collections/tests/Generic/HashSet/HashSet.Generic.Tests.cs b/src/libraries/System.Collections/tests/Generic/HashSet/HashSet.Generic.Tests.cs
index 19b2e3f000bba2..d3be892a88bd96 100644
--- a/src/libraries/System.Collections/tests/Generic/HashSet/HashSet.Generic.Tests.cs
+++ b/src/libraries/System.Collections/tests/Generic/HashSet/HashSet.Generic.Tests.cs
@@ -142,14 +142,11 @@ public void HashSet_CreateWithCapacity_CapacityAtLeastPassedValue(int capacity)
         [Fact]
         public void HashSetResized_CapacityChanged()
         {
-            var hashSet = (HashSet<T>)GenericISetFactory(10);
+            var hashSet = (HashSet<T>)GenericISetFactory(3);
             int initialCapacity = hashSet.Capacity;
 
             int seed = 85877;
-            for (int i = 0; i < hashSet.Capacity; i++)
-            {
-                hashSet.Add(CreateT(seed++));
-            }
+            hashSet.Add(CreateT(seed++));
 
             int afterCapacity = hashSet.Capacity;
 

From aa3ed0690bd1b8127d2446950bf5ad406c232554 Mon Sep 17 00:00:00 2001
From: hrrrrustic <hrrrrustic@gmail.com>
Date: Fri, 4 Aug 2023 22:29:32 +0300
Subject: [PATCH 12/17] stack & queue update

---
 .../System.Collections/src/System/Collections/Generic/Stack.cs  | 2 +-
 .../src/System/Collections/Generic/Queue.cs                     | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/libraries/System.Collections/src/System/Collections/Generic/Stack.cs b/src/libraries/System.Collections/src/System/Collections/Generic/Stack.cs
index 63d37ba0b186c4..10f1b58c4fa149 100644
--- a/src/libraries/System.Collections/src/System/Collections/Generic/Stack.cs
+++ b/src/libraries/System.Collections/src/System/Collections/Generic/Stack.cs
@@ -178,7 +178,7 @@ public void TrimExcess()
         public void TrimExcess(int capacity)
         {
             ArgumentOutOfRangeException.ThrowIfNegative(capacity);
-            ArgumentOutOfRangeException.ThrowIfLessThan(capacity, _array.Length);
+            ArgumentOutOfRangeException.ThrowIfLessThan(capacity, _size);
 
             if (capacity == _array.Length)
                 return;
diff --git a/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/Queue.cs b/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/Queue.cs
index 144ad3af777b2d..8433cda6896401 100644
--- a/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/Queue.cs
+++ b/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/Queue.cs
@@ -365,7 +365,7 @@ public void TrimExcess()
         public void TrimExcess(int capacity)
         {
             ArgumentOutOfRangeException.ThrowIfNegative(capacity);
-            ArgumentOutOfRangeException.ThrowIfLessThan(capacity, _array.Length);
+            ArgumentOutOfRangeException.ThrowIfLessThan(capacity, _size);
 
             if (capacity == _array.Length)
                 return;

From 03111906e9e266a420550727f26243e8677e137a Mon Sep 17 00:00:00 2001
From: hrrrrustic <hrrrrustic@gmail.com>
Date: Sun, 24 Sep 2023 23:03:03 +0300
Subject: [PATCH 13/17] Fix hashset

---
 .../src/System/Collections/Generic/HashSet.cs            | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/HashSet.cs b/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/HashSet.cs
index e8d974423d2217..d49c0467c5e88c 100644
--- a/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/HashSet.cs
+++ b/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/HashSet.cs
@@ -1013,17 +1013,14 @@ private void Resize(int newSize, bool forceNewHashCodes)
         public void TrimExcess() => SetCapacity(Count);
 
         /// <summary>
-        /// Sets the capacity of a <see cref="HashSet{T}"/> object to the specified number of entries.
+        /// Sets the capacity of a <see cref="HashSet{T}"/> object to the specified number of entries,
+        /// rounded up to a nearby, implementation-specific value.
         /// </summary>
         /// <param name="capacity">The new capacity.</param>
         /// <exception cref="ArgumentOutOfRangeException">Passed capacity is lower than entries count.</exception>
         public void TrimExcess(int capacity)
         {
-            var currentCount = Count;
-            ArgumentOutOfRangeException.ThrowIfLessThan(capacity, currentCount);
-
-            if (capacity == currentCount)
-                return;
+            ArgumentOutOfRangeException.ThrowIfLessThan(capacity, Count);
 
             SetCapacity(capacity);
         }

From 6e055cdad0a2745da0224a4f0d4faa2426f74061 Mon Sep 17 00:00:00 2001
From: hrrrrustic <hrrrrustic@gmail.com>
Date: Sun, 24 Sep 2023 23:09:21 +0300
Subject: [PATCH 14/17] inherit doc

---
 .../System.Collections/src/System/Collections/Generic/Stack.cs   | 1 +
 .../src/System/Collections/Generic/Queue.cs                      | 1 +
 2 files changed, 2 insertions(+)

diff --git a/src/libraries/System.Collections/src/System/Collections/Generic/Stack.cs b/src/libraries/System.Collections/src/System/Collections/Generic/Stack.cs
index 10f1b58c4fa149..ccc83e9d6504f2 100644
--- a/src/libraries/System.Collections/src/System/Collections/Generic/Stack.cs
+++ b/src/libraries/System.Collections/src/System/Collections/Generic/Stack.cs
@@ -62,6 +62,7 @@ public Stack(IEnumerable<T> collection)
         /// </summary>
         public int Capacity => _array.Length;
 
+        /// <inheritdoc/>
         bool ICollection.IsSynchronized => false;
 
         object ICollection.SyncRoot => this;
diff --git a/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/Queue.cs b/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/Queue.cs
index 8433cda6896401..fe8f1138d1c337 100644
--- a/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/Queue.cs
+++ b/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/Queue.cs
@@ -59,6 +59,7 @@ public Queue(IEnumerable<T> collection)
         /// </summary>
         public int Capacity => _array.Length;
 
+        /// <inheritdoc/>
         bool ICollection.IsSynchronized => false;
 
         object ICollection.SyncRoot => this;

From 534c2f446fe4484277a919140fdee7da72cde600 Mon Sep 17 00:00:00 2001
From: hrrrrustic <hrrrrustic@gmail.com>
Date: Sun, 24 Sep 2023 23:37:51 +0300
Subject: [PATCH 15/17] update inherit docs

---
 .../System.Collections/src/System/Collections/Generic/Stack.cs  | 2 +-
 .../src/System/Collections/Generic/Queue.cs                     | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/libraries/System.Collections/src/System/Collections/Generic/Stack.cs b/src/libraries/System.Collections/src/System/Collections/Generic/Stack.cs
index ccc83e9d6504f2..1317ed240c06a3 100644
--- a/src/libraries/System.Collections/src/System/Collections/Generic/Stack.cs
+++ b/src/libraries/System.Collections/src/System/Collections/Generic/Stack.cs
@@ -62,7 +62,7 @@ public Stack(IEnumerable<T> collection)
         /// </summary>
         public int Capacity => _array.Length;
 
-        /// <inheritdoc/>
+        /// <inheritdoc cref="ICollection{T}"/>
         bool ICollection.IsSynchronized => false;
 
         object ICollection.SyncRoot => this;
diff --git a/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/Queue.cs b/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/Queue.cs
index fe8f1138d1c337..4a7efdf06b54da 100644
--- a/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/Queue.cs
+++ b/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/Queue.cs
@@ -59,7 +59,7 @@ public Queue(IEnumerable<T> collection)
         /// </summary>
         public int Capacity => _array.Length;
 
-        /// <inheritdoc/>
+        /// <inheritdoc cref="ICollection{T}"/>
         bool ICollection.IsSynchronized => false;
 
         object ICollection.SyncRoot => this;

From a66770dcf3dbac055a4dac4b111d5c4c5c3271bc Mon Sep 17 00:00:00 2001
From: hrrrrustic <hrrrrustic@gmail.com>
Date: Mon, 25 Sep 2023 00:03:47 +0300
Subject: [PATCH 16/17] update tests

---
 .../tests/Generic/HashSet/HashSet.Generic.Tests.cs          | 6 +++---
 .../tests/Generic/Queue/Queue.Generic.Tests.cs              | 3 +--
 2 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/src/libraries/System.Collections/tests/Generic/HashSet/HashSet.Generic.Tests.cs b/src/libraries/System.Collections/tests/Generic/HashSet/HashSet.Generic.Tests.cs
index d3be892a88bd96..038bbbdb960c3f 100644
--- a/src/libraries/System.Collections/tests/Generic/HashSet/HashSet.Generic.Tests.cs
+++ b/src/libraries/System.Collections/tests/Generic/HashSet/HashSet.Generic.Tests.cs
@@ -215,9 +215,9 @@ public void HashSet_TrimAccessWithInvalidArg_ThrowOutOfRange(int size, int newCa
         [Fact]
         public void TrimExcess_Generic_LargeInitialCapacity_TrimReducesSize()
         {
-            var dictionary = new HashSet<T>(20);
-            dictionary.TrimExcess(7);
-            Assert.Equal(7, dictionary.EnsureCapacity(0));
+            var set = new HashSet<T>(20);
+            set.TrimExcess(7);
+            Assert.Equal(7, set.Capacity);
         }
 
         [Theory]
diff --git a/src/libraries/System.Collections/tests/Generic/Queue/Queue.Generic.Tests.cs b/src/libraries/System.Collections/tests/Generic/Queue/Queue.Generic.Tests.cs
index dc857cb5867eac..a2ce3d94f9c665 100644
--- a/src/libraries/System.Collections/tests/Generic/Queue/Queue.Generic.Tests.cs
+++ b/src/libraries/System.Collections/tests/Generic/Queue/Queue.Generic.Tests.cs
@@ -225,8 +225,7 @@ public void Queue_TrimAccessWithInvalidArg_ThrowOutOfRange(int size, int newCapa
         [Fact]
         public void Queue_TrimAccessCurrentCount_DoesNothing()
         {
-            var queue = new Queue<T>();
-            queue.Enqueue(CreateT(85877));
+            var queue = GenericQueueFactory(100);
             queue.TrimExcess(queue.Count);
             int capacity = queue.Capacity;
             queue.TrimExcess(queue.Count);

From 12467769cda68dcd0f6cbc49829984b0a033328e Mon Sep 17 00:00:00 2001
From: Eirik Tsarpalis <eirik.tsarpalis@gmail.com>
Date: Wed, 22 Nov 2023 10:58:38 +0000
Subject: [PATCH 17/17] Address remaining feedback

---
 .../Generic/Queue/Queue.Generic.Tests.cs      | 21 ++++++++++++-------
 .../src/System/Collections/Generic/HashSet.cs |  1 +
 .../src/System/Collections/Generic/Queue.cs   |  1 +
 3 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/src/libraries/System.Collections/tests/Generic/Queue/Queue.Generic.Tests.cs b/src/libraries/System.Collections/tests/Generic/Queue/Queue.Generic.Tests.cs
index a2ce3d94f9c665..7c900d4c6ef325 100644
--- a/src/libraries/System.Collections/tests/Generic/Queue/Queue.Generic.Tests.cs
+++ b/src/libraries/System.Collections/tests/Generic/Queue/Queue.Generic.Tests.cs
@@ -21,9 +21,9 @@ protected Queue<T> GenericQueueFactory()
             return new Queue<T>();
         }
 
-        protected Queue<T> GenericQueueFactory(int count)
+        protected Queue<T> GenericQueueFactory(int count, int? capacity = null)
         {
-            Queue<T> queue = new Queue<T>(count);
+            Queue<T> queue = new Queue<T>(capacity ?? count);
             int seed = count * 34;
             for (int i = 0; i < count; i++)
                 queue.Enqueue(CreateT(seed++));
@@ -223,14 +223,21 @@ public void Queue_TrimAccessWithInvalidArg_ThrowOutOfRange(int size, int newCapa
         }
 
         [Fact]
-        public void Queue_TrimAccessCurrentCount_DoesNothing()
+        public void Queue_TrimAccessCurrentCount_ReducesToCount()
         {
-            var queue = GenericQueueFactory(100);
+            var queue = GenericQueueFactory(20, capacity: 30);
+            Assert.Equal(30, queue.Capacity);
+            Assert.Equal(20, queue.Count);
+
             queue.TrimExcess(queue.Count);
-            int capacity = queue.Capacity;
+
+            Assert.Equal(20, queue.Capacity);
+            Assert.Equal(20, queue.Count);
+
             queue.TrimExcess(queue.Count);
-            int capacityAgain = queue.Capacity;
-            Assert.Equal(capacity, capacityAgain);
+
+            Assert.Equal(20, queue.Capacity);
+            Assert.Equal(20, queue.Count);
         }
 
         [Theory]
diff --git a/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/HashSet.cs b/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/HashSet.cs
index d49c0467c5e88c..460e6a8940d6a9 100644
--- a/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/HashSet.cs
+++ b/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/HashSet.cs
@@ -1027,6 +1027,7 @@ public void TrimExcess(int capacity)
 
         private void SetCapacity(int capacity)
         {
+            Debug.Assert(capacity >= Count);
             int newSize = HashHelpers.GetPrime(capacity);
             Entry[]? oldEntries = _entries;
             int currentCapacity = oldEntries == null ? 0 : oldEntries.Length;
diff --git a/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/Queue.cs b/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/Queue.cs
index 4a7efdf06b54da..58afecf920c442 100644
--- a/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/Queue.cs
+++ b/src/libraries/System.Private.CoreLib/src/System/Collections/Generic/Queue.cs
@@ -309,6 +309,7 @@ public T[] ToArray()
         // must be >= _size.
         private void SetCapacity(int capacity)
         {
+            Debug.Assert(capacity >= _size);
             T[] newarray = new T[capacity];
             if (_size > 0)
             {