Extensions for immutable collection builders (#21055)

src/System.Collections.Immutable/ref/System.Collections.Immutable.cs

@@ -92,6 +92,7 @@ public static partial class ImmutableArray
         public static System.Collections.Immutable.ImmutableArray<T> Create<T>(params T[] items) { throw null; }
         public static System.Collections.Immutable.ImmutableArray<T> Create<T>(T[] items, int start, int length) { throw null; }
         public static System.Collections.Immutable.ImmutableArray<TSource> ToImmutableArray<TSource>(this System.Collections.Generic.IEnumerable<TSource> items) { throw null; }
+        public static System.Collections.Immutable.ImmutableArray<TSource> ToImmutableArray<TSource>(this System.Collections.Immutable.ImmutableArray<TSource>.Builder builder) { throw null; }
     }
     public partial struct ImmutableArray<T> : System.Collections.Generic.ICollection<T>, System.Collections.Generic.IEnumerable<T>, System.Collections.Generic.IList<T>, System.Collections.Generic.IReadOnlyCollection<T>, System.Collections.Generic.IReadOnlyList<T>, System.Collections.ICollection, System.Collections.IEnumerable, System.Collections.IList, System.Collections.Immutable.IImmutableList<T>, System.Collections.IStructuralComparable, System.Collections.IStructuralEquatable, System.IEquatable<System.Collections.Immutable.ImmutableArray<T>>
     {
@@ -270,6 +271,7 @@ public static partial class ImmutableDictionary
         public static System.Collections.Immutable.ImmutableDictionary<TKey, TValue> ToImmutableDictionary<TSource, TKey, TValue>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, TKey> keySelector, System.Func<TSource, TValue> elementSelector) { throw null; }
         public static System.Collections.Immutable.ImmutableDictionary<TKey, TValue> ToImmutableDictionary<TSource, TKey, TValue>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, TKey> keySelector, System.Func<TSource, TValue> elementSelector, System.Collections.Generic.IEqualityComparer<TKey> keyComparer) { throw null; }
         public static System.Collections.Immutable.ImmutableDictionary<TKey, TValue> ToImmutableDictionary<TSource, TKey, TValue>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, TKey> keySelector, System.Func<TSource, TValue> elementSelector, System.Collections.Generic.IEqualityComparer<TKey> keyComparer, System.Collections.Generic.IEqualityComparer<TValue> valueComparer) { throw null; }
+        public static System.Collections.Immutable.ImmutableDictionary<TKey, TValue> ToImmutableDictionary<TKey, TValue>(this System.Collections.Immutable.ImmutableDictionary<TKey, TValue>.Builder builder) { throw null; }
     }
     public sealed partial class ImmutableDictionary<TKey, TValue> : System.Collections.Generic.ICollection<System.Collections.Generic.KeyValuePair<TKey, TValue>>, System.Collections.Generic.IDictionary<TKey, TValue>, System.Collections.Generic.IEnumerable<System.Collections.Generic.KeyValuePair<TKey, TValue>>, System.Collections.Generic.IReadOnlyCollection<System.Collections.Generic.KeyValuePair<TKey, TValue>>, System.Collections.Generic.IReadOnlyDictionary<TKey, TValue>, System.Collections.ICollection, System.Collections.IDictionary, System.Collections.IEnumerable, System.Collections.Immutable.IImmutableDictionary<TKey, TValue>
     {
@@ -398,6 +400,7 @@ public static partial class ImmutableHashSet
         public static System.Collections.Immutable.ImmutableHashSet<T> Create<T>(params T[] items) { throw null; }
         public static System.Collections.Immutable.ImmutableHashSet<TSource> ToImmutableHashSet<TSource>(this System.Collections.Generic.IEnumerable<TSource> source) { throw null; }
         public static System.Collections.Immutable.ImmutableHashSet<TSource> ToImmutableHashSet<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Collections.Generic.IEqualityComparer<TSource> equalityComparer) { throw null; }
+        public static System.Collections.Immutable.ImmutableHashSet<TSource> ToImmutableHashSet<TSource>(this System.Collections.Immutable.ImmutableHashSet<TSource>.Builder builder) { throw null; }
     }
     public sealed partial class ImmutableHashSet<T> : System.Collections.Generic.ICollection<T>, System.Collections.Generic.IEnumerable<T>, System.Collections.Generic.IReadOnlyCollection<T>, System.Collections.Generic.ISet<T>, System.Collections.ICollection, System.Collections.IEnumerable, System.Collections.Immutable.IImmutableSet<T>
     {
@@ -522,6 +525,7 @@ public static partial class ImmutableList
         public static System.Collections.Immutable.IImmutableList<T> Remove<T>(this System.Collections.Immutable.IImmutableList<T> list, T value) { throw null; }
         public static System.Collections.Immutable.IImmutableList<T> Replace<T>(this System.Collections.Immutable.IImmutableList<T> list, T oldValue, T newValue) { throw null; }
         public static System.Collections.Immutable.ImmutableList<TSource> ToImmutableList<TSource>(this System.Collections.Generic.IEnumerable<TSource> source) { throw null; }
+        public static System.Collections.Immutable.ImmutableList<TSource> ToImmutableList<TSource>(this System.Collections.Immutable.ImmutableList<TSource>.Builder builder) { throw null; }
     }
     public sealed partial class ImmutableList<T> : System.Collections.Generic.ICollection<T>, System.Collections.Generic.IEnumerable<T>, System.Collections.Generic.IList<T>, System.Collections.Generic.IReadOnlyCollection<T>, System.Collections.Generic.IReadOnlyList<T>, System.Collections.ICollection, System.Collections.IEnumerable, System.Collections.IList, System.Collections.Immutable.IImmutableList<T>
     {
@@ -746,6 +750,7 @@ public static partial class ImmutableSortedDictionary
         public static System.Collections.Immutable.ImmutableSortedDictionary<TKey, TValue> ToImmutableSortedDictionary<TSource, TKey, TValue>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, TKey> keySelector, System.Func<TSource, TValue> elementSelector) { throw null; }
         public static System.Collections.Immutable.ImmutableSortedDictionary<TKey, TValue> ToImmutableSortedDictionary<TSource, TKey, TValue>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, TKey> keySelector, System.Func<TSource, TValue> elementSelector, System.Collections.Generic.IComparer<TKey> keyComparer) { throw null; }
         public static System.Collections.Immutable.ImmutableSortedDictionary<TKey, TValue> ToImmutableSortedDictionary<TSource, TKey, TValue>(this System.Collections.Generic.IEnumerable<TSource> source, System.Func<TSource, TKey> keySelector, System.Func<TSource, TValue> elementSelector, System.Collections.Generic.IComparer<TKey> keyComparer, System.Collections.Generic.IEqualityComparer<TValue> valueComparer) { throw null; }
+        public static System.Collections.Immutable.ImmutableSortedDictionary<TKey, TValue> ToImmutableSortedDictionary<TKey, TValue>(this System.Collections.Immutable.ImmutableSortedDictionary<TKey, TValue>.Builder source) { throw null; }
     }
     public sealed partial class ImmutableSortedDictionary<TKey, TValue> : System.Collections.Generic.ICollection<System.Collections.Generic.KeyValuePair<TKey, TValue>>, System.Collections.Generic.IDictionary<TKey, TValue>, System.Collections.Generic.IEnumerable<System.Collections.Generic.KeyValuePair<TKey, TValue>>, System.Collections.Generic.IReadOnlyCollection<System.Collections.Generic.KeyValuePair<TKey, TValue>>, System.Collections.Generic.IReadOnlyDictionary<TKey, TValue>, System.Collections.ICollection, System.Collections.IDictionary, System.Collections.IEnumerable, System.Collections.Immutable.IImmutableDictionary<TKey, TValue>
     {
@@ -881,6 +886,7 @@ public static partial class ImmutableSortedSet
         public static System.Collections.Immutable.ImmutableSortedSet<T> Create<T>(params T[] items) { throw null; }
         public static System.Collections.Immutable.ImmutableSortedSet<TSource> ToImmutableSortedSet<TSource>(this System.Collections.Generic.IEnumerable<TSource> source) { throw null; }
         public static System.Collections.Immutable.ImmutableSortedSet<TSource> ToImmutableSortedSet<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, System.Collections.Generic.IComparer<TSource> comparer) { throw null; }
+        public static System.Collections.Immutable.ImmutableSortedSet<TSource> ToImmutableSortedSet<TSource>(this System.Collections.Immutable.ImmutableSortedSet<TSource>.Builder builder) { throw null; }
     }
     public sealed partial class ImmutableSortedSet<T> : System.Collections.Generic.ICollection<T>, System.Collections.Generic.IEnumerable<T>, System.Collections.Generic.IList<T>, System.Collections.Generic.IReadOnlyCollection<T>, System.Collections.Generic.IReadOnlyList<T>, System.Collections.Generic.ISet<T>, System.Collections.ICollection, System.Collections.IEnumerable, System.Collections.IList, System.Collections.Immutable.IImmutableSet<T>
     {

src/System.Collections.Immutable/src/System/Collections/Immutable/ImmutableArray.cs

@@ -395,6 +395,19 @@ public static ImmutableArray<TSource> ToImmutableArray<TSource>(this IEnumerable
             return CreateRange(items);
         }
 
+        /// <summary>
+        /// Returns an immutable copy of the current contents of the builder's collection.
+        /// </summary>
+        /// <param name="builder">The builder to create the immutable array from.</param>
+        /// <returns>An immutable array.</returns>
+        [Pure]
+        public static ImmutableArray<TSource> ToImmutableArray<TSource>(this ImmutableArray<TSource>.Builder builder)
+        {
+            Requires.NotNull(builder, nameof(builder));
+
+            return builder.ToImmutable();
+        }
+
         /// <summary>
         /// Searches an entire one-dimensional sorted <see cref="ImmutableArray{T}"/> for a specific element,
         /// using the <see cref="IComparable{T}"/> generic interface implemented by each element

src/System.Collections.Immutable/src/System/Collections/Immutable/ImmutableDictionary.cs

@@ -166,6 +166,19 @@ public static ImmutableDictionary<TKey, TValue> ToImmutableDictionary<TSource, T
                 .AddRange(source.Select(element => new KeyValuePair<TKey, TValue>(keySelector(element), elementSelector(element))));
         }
 
+        /// <summary>
+        /// Returns an immutable copy of the current contents of the builder's collection.
+        /// </summary>
+        /// <param name="builder">The builder to create the immutable dictionary from.</param>
+        /// <returns>An immutable dictionary.</returns>
+        [Pure]
+        public static ImmutableDictionary<TKey, TValue> ToImmutableDictionary<TKey, TValue>(this ImmutableDictionary<TKey, TValue>.Builder builder)
+        {
+            Requires.NotNull(builder, nameof(builder));
+
+            return builder.ToImmutable();
+        }
+
         /// <summary>
         /// Constructs an immutable dictionary based on some transformation of a sequence.
         /// </summary>

src/System.Collections.Immutable/src/System/Collections/Immutable/ImmutableHashSet.cs

@@ -156,6 +156,20 @@ public static ImmutableHashSet<TSource> ToImmutableHashSet<TSource>(this IEnumer
             return ImmutableHashSet<TSource>.Empty.WithComparer(equalityComparer).Union(source);
         }
 
+        /// <summary>
+        /// Returns an immutable copy of the current contents of the builder's collection.
+        /// </summary>
+        /// <param name="builder">The builder to create the immutable set from.</param>
+        /// <returns>An immutable set.</returns>
+        [Pure]
+        public static ImmutableHashSet<TSource> ToImmutableHashSet<TSource>(this ImmutableHashSet<TSource>.Builder builder)
+        {
+            Requires.NotNull(builder, nameof(builder));
+
+            return builder.ToImmutable();
+        }
+
+
         /// <summary>
         /// Enumerates a sequence exactly once and produces an immutable set of its contents.
         /// </summary>

src/System.Collections.Immutable/src/System/Collections/Immutable/ImmutableList.cs

@@ -73,6 +73,19 @@ public static ImmutableList<TSource> ToImmutableList<TSource>(this IEnumerable<T
             return ImmutableList<TSource>.Empty.AddRange(source);
         }
 
+        /// <summary>
+        /// Returns an immutable copy of the current contents of the builder's collection.
+        /// </summary>
+        /// <param name="builder">The builder to create the immutable list from.</param>
+        /// <returns>An immutable list.</returns>
+        [Pure]
+        public static ImmutableList<TSource> ToImmutableList<TSource>(this ImmutableList<TSource>.Builder builder)
+        {
+            Requires.NotNull(builder, nameof(builder));
+
+            return builder.ToImmutable();
+        }
+
         /// <summary>
         /// Replaces the first equal element in the list with the specified element.
         /// </summary>

src/System.Collections.Immutable/src/System/Collections/Immutable/ImmutableSortedDictionary.cs

@@ -162,6 +162,19 @@ public static ImmutableSortedDictionary<TKey, TValue> ToImmutableSortedDictionar
                 .AddRange(source.Select(element => new KeyValuePair<TKey, TValue>(keySelector(element), elementSelector(element))));
         }
 
+        /// <summary>
+        /// Returns an immutable copy of the current contents of the builder's collection.
+        /// </summary>
+        /// <param name="builder">The builder to create the immutable map from.</param>
+        /// <returns>An immutable map.</returns>
+        [Pure]
+        public static ImmutableSortedDictionary<TKey, TValue> ToImmutableSortedDictionary<TKey, TValue>(this ImmutableSortedDictionary<TKey, TValue>.Builder builder)
+        {
+            Requires.NotNull(builder, nameof(builder));
+
+            return builder.ToImmutable();
+        }
+
         /// <summary>
         /// Constructs an immutable sorted dictionary based on some transformation of a sequence.
         /// </summary>

src/System.Collections.Immutable/src/System/Collections/Immutable/ImmutableSortedSet.cs

@@ -167,5 +167,18 @@ public static ImmutableSortedSet<TSource> ToImmutableSortedSet<TSource>(this IEn
         {
             return ToImmutableSortedSet(source, null);
         }
+
+        /// <summary>
+        /// Returns an immutable copy of the current contents of the builder's collection.
+        /// </summary>
+        /// <param name="builder">The builder to create the immutable set from.</param>
+        /// <returns>An immutable set.</returns>
+        [Pure]
+        public static ImmutableSortedSet<TSource> ToImmutableSortedSet<TSource>(this ImmutableSortedSet<TSource>.Builder builder)
+        {
+            Requires.NotNull(builder, nameof(builder));
+
+            return builder.ToImmutable();
+        }
     }
 }

src/System.Collections.Immutable/tests/ImmutableArrayBuilderTest.cs

@@ -455,6 +455,29 @@ public void ToImmutable()
             Assert.True(builder.ToImmutable().IsEmpty);
         }
 
+        [Fact]
+        public void ToImmutableArray()
+        {
+            var builder = new ImmutableArray<int>.Builder();
+            builder.AddRange(0, 1, 2);
+
+            var array = builder.ToImmutableArray();
+            Assert.Equal(0, array[0]);
+            Assert.Equal(1, array[1]);
+            Assert.Equal(2, array[2]);
+
+            builder[1] = 5;
+            Assert.Equal(5, builder[1]);
+            Assert.Equal(1, array[1]);
+
+            builder.Clear();
+            Assert.True(builder.ToImmutableArray().IsEmpty);
+            Assert.False(array.IsEmpty);
+
+            ImmutableArray<int>.Builder nullBuilder = null;
+            AssertExtensions.Throws<ArgumentNullException>("builder", () => nullBuilder.ToImmutableArray());
+        }
+
         [Fact]
         public void CopyTo()
         {

src/System.Collections.Immutable/tests/ImmutableDictionaryBuilderTest.cs

@@ -270,6 +270,31 @@ public static void TestDebuggerAttributes_Null()
             Assert.IsType<ArgumentNullException>(tie.InnerException);
         }
 
+        [Fact]
+        public void ToImmutableDictionary()
+        {
+            ImmutableDictionary<int, int>.Builder builder =  ImmutableDictionary.CreateBuilder<int, int>();
+            builder.Add(0, 0);
+            builder.Add(1, 1);
+            builder.Add(2, 2);
+
+            var dictionary = builder.ToImmutableDictionary();
+            Assert.Equal(0, dictionary[0]);
+            Assert.Equal(1, dictionary[1]);
+            Assert.Equal(2, dictionary[2]);
+
+            builder[1] = 5;
+            Assert.Equal(5, builder[1]);
+            Assert.Equal(1, dictionary[1]);
+
+            builder.Clear();
+            Assert.True(builder.ToImmutableDictionary().IsEmpty);
+            Assert.False(dictionary.IsEmpty);
+
+            ImmutableDictionary<int, int>.Builder nullBuilder = null;
+            AssertExtensions.Throws<ArgumentNullException>("builder", () => nullBuilder.ToImmutableDictionary());
+        }
+
         protected override IImmutableDictionary<TKey, TValue> GetEmptyImmutableDictionary<TKey, TValue>()
         {
             return ImmutableDictionary.Create<TKey, TValue>();

src/System.Collections.Immutable/tests/ImmutableHashSetBuilderTest.cs

@@ -308,5 +308,30 @@ public void DebuggerAttributesValid()
         {
             DebuggerAttributes.ValidateDebuggerDisplayReferences(ImmutableHashSet.CreateBuilder<int>());
         }
+
+        [Fact]
+        public void ToImmutableHashSet()
+        {
+            ImmutableHashSet<int>.Builder builder = ImmutableHashSet.CreateBuilder<int>();
+            builder.Add(1);
+            builder.Add(2);
+            builder.Add(3);
+
+            var set = builder.ToImmutableSortedSet();
+            Assert.True(builder.Contains(1));
+            Assert.True(builder.Contains(2));
+            Assert.True(builder.Contains(3));
+
+            builder.Remove(3);
+            Assert.False(builder.Contains(3));
+            Assert.True(set.Contains(3));
+
+            builder.Clear();
+            Assert.True(builder.ToImmutableHashSet().IsEmpty);
+            Assert.False(set.IsEmpty);
+
+            ImmutableHashSet<int>.Builder nullBuilder = null;
+            AssertExtensions.Throws<ArgumentNullException>("builder", () => nullBuilder.ToImmutableHashSet());
+        }
     }
 }

src/System.Collections.Immutable/tests/ImmutableListBuilderTest.cs

@@ -390,6 +390,31 @@ public void ItemRef_OutOfBounds()
             Assert.Throws<ArgumentOutOfRangeException>(() => builder.ItemRef(5));
         }
 
+        [Fact]
+        public void ToImmutableList()
+        {
+            ImmutableList<int>.Builder builder = ImmutableList.CreateBuilder<int>();
+            builder.Add(0);
+            builder.Add(1);
+            builder.Add(2);
+
+            var list = builder.ToImmutableList();
+            Assert.Equal(0, builder[0]);
+            Assert.Equal(1, builder[1]);
+            Assert.Equal(2, builder[2]);
+
+            builder[1] = 5;
+            Assert.Equal(5, builder[1]);
+            Assert.Equal(1, list[1]);
+
+            builder.Clear();
+            Assert.True(builder.ToImmutableList().IsEmpty);
+            Assert.False(list.IsEmpty);
+
+            ImmutableList<int>.Builder nullBuilder = null;
+            AssertExtensions.Throws<ArgumentNullException>("builder", () => nullBuilder.ToImmutableList());
+        }
+
         protected override IEnumerable<T> GetEnumerableOf<T>(params T[] contents)
         {
             return ImmutableList<T>.Empty.AddRange(contents).ToBuilder();

src/System.Collections.Immutable/tests/ImmutableSortedDictionaryBuilderTest.cs

@@ -310,6 +310,31 @@ public void ValueRef_NonExistentKey()
             Assert.Throws<KeyNotFoundException>(() => builder.ValueRef("c"));
         }
 
+        [Fact]
+        public void ToImmutableSortedDictionary()
+        {
+            ImmutableSortedDictionary<int, int>.Builder builder = ImmutableSortedDictionary.CreateBuilder<int, int>();
+            builder.Add(1, 1);
+            builder.Add(2, 2);
+            builder.Add(3, 3);
+
+            var dictionary = builder.ToImmutableSortedDictionary();
+            Assert.Equal(1, dictionary[1]);
+            Assert.Equal(2, dictionary[2]);
+            Assert.Equal(3, dictionary[3]);
+
+            builder[2] = 5;
+            Assert.Equal(5, builder[2]);
+            Assert.Equal(2, dictionary[2]);
+
+            builder.Clear();
+            Assert.True(builder.ToImmutableSortedDictionary().IsEmpty);
+            Assert.False(dictionary.IsEmpty);
+
+            ImmutableSortedDictionary<int, int>.Builder nullBuilder = null;
+            AssertExtensions.Throws<ArgumentNullException>("builder", () => nullBuilder.ToImmutableSortedDictionary());
+        }
+
         protected override IImmutableDictionary<TKey, TValue> GetEmptyImmutableDictionary<TKey, TValue>()
         {
             return ImmutableSortedDictionary.Create<TKey, TValue>();