Add IList<T> and related APIs to JsonObject.

src/libraries/System.Collections/src/System/Collections/Generic/OrderedDictionary.cs

@@ -809,8 +809,8 @@ public void SetAt(int index, TKey key, TValue value)
             }
 
             // The key doesn't match that index. If it exists elsewhere in the collection, fail.
-            uint _ = 0, collisionCount = 0;
-            if (IndexOf(key, ref _, ref collisionCount) >= 0)
+            uint hashCode = 0, collisionCount = 0;
+            if (IndexOf(key, ref hashCode, ref collisionCount) >= 0)
             {
                 ThrowHelper.ThrowDuplicateKey(key);
             }
@@ -820,6 +820,7 @@ public void SetAt(int index, TKey key, TValue value)
             // (we could check for this, but in a properly balanced dictionary the chances should
             // be low for a match, so it's not worth it).
             RemoveEntryFromBucket(index);
+            e.HashCode = hashCode;
             e.Key = key;
             e.Value = value;
             PushEntryIntoBucket(ref e, index);

src/libraries/System.Collections/tests/Generic/OrderedDictionary/OrderedDictionary.Generic.Tests.cs

@@ -308,6 +308,25 @@ public void OrderedDictionary_Generic_SetAt_GetAt_Roundtrip(int count)
             }
         }
 
+        [Fact]
+        public void OrderedDictionary_SetAt_KeyValuePairSubsequentlyAvailable()
+        {
+            TKey key0 = CreateTKey(0), key1 = CreateTKey(1);
+            TValue value0 = CreateTValue(0), value1 = CreateTValue(1);
+
+            var dict = new OrderedDictionary<TKey, TValue>
+            {
+                [key0] = value0,
+            };
+
+            dict.SetAt(index: 0, key1, value1);
+
+            Assert.Equal(1, dict.Count);
+            Assert.Equal([new(key1, value1)], dict);
+            Assert.False(dict.ContainsKey(key0));
+            Assert.True(dict.ContainsKey(key1));
+        }
+
         #endregion
 
         #region Remove(..., out TValue)

src/libraries/System.Text.Json/ref/System.Text.Json.cs

@@ -706,11 +706,11 @@ internal JsonNode() { }
         public System.Text.Json.Nodes.JsonValue AsValue() { throw null; }
         public System.Text.Json.Nodes.JsonNode DeepClone() { throw null; }
         public static bool DeepEquals(System.Text.Json.Nodes.JsonNode? node1, System.Text.Json.Nodes.JsonNode? node2) { throw null; }
-        public string GetPropertyName() { throw null; }
+        public int GetElementIndex() { throw null; }
         public string GetPath() { throw null; }
+        public string GetPropertyName() { throw null; }
+        public System.Text.Json.JsonValueKind GetValueKind() { throw null; }
         public virtual T GetValue<T>() { throw null; }
-        public JsonValueKind GetValueKind() { throw null; }
-        public int GetElementIndex() { throw null; }
         public static explicit operator bool (System.Text.Json.Nodes.JsonNode value) { throw null; }
         public static explicit operator byte (System.Text.Json.Nodes.JsonNode value) { throw null; }
         public static explicit operator char (System.Text.Json.Nodes.JsonNode value) { throw null; }
@@ -801,7 +801,7 @@ internal JsonNode() { }
         public static System.Threading.Tasks.Task<System.Text.Json.Nodes.JsonNode?> ParseAsync(System.IO.Stream utf8Json, System.Text.Json.Nodes.JsonNodeOptions? nodeOptions = default(System.Text.Json.Nodes.JsonNodeOptions?), System.Text.Json.JsonDocumentOptions documentOptions = default(System.Text.Json.JsonDocumentOptions), System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) { throw null; }
         [System.Diagnostics.CodeAnalysis.RequiresDynamicCodeAttribute("Creating JsonValue instances with non-primitive types requires generating code at runtime.")]
         [System.Diagnostics.CodeAnalysis.RequiresUnreferencedCodeAttribute("Creating JsonValue instances with non-primitive types is not compatible with trimming. It can result in non-primitive types being serialized, which may have their members trimmed.")]
-        public void ReplaceWith<T>(T value) { throw null; }
+        public void ReplaceWith<T>(T value) { }
         public string ToJsonString(System.Text.Json.JsonSerializerOptions? options = null) { throw null; }
         public override string ToString() { throw null; }
         public abstract void WriteTo(System.Text.Json.Utf8JsonWriter writer, System.Text.Json.JsonSerializerOptions? options = null);
@@ -811,25 +811,35 @@ public partial struct JsonNodeOptions
         private int _dummyPrimitive;
         public bool PropertyNameCaseInsensitive { readonly get { throw null; } set { } }
     }
-    public sealed partial class JsonObject : System.Text.Json.Nodes.JsonNode, System.Collections.Generic.ICollection<System.Collections.Generic.KeyValuePair<string, System.Text.Json.Nodes.JsonNode?>>, System.Collections.Generic.IDictionary<string, System.Text.Json.Nodes.JsonNode?>, System.Collections.Generic.IEnumerable<System.Collections.Generic.KeyValuePair<string, System.Text.Json.Nodes.JsonNode?>>, System.Collections.IEnumerable
+    public sealed partial class JsonObject : System.Text.Json.Nodes.JsonNode, System.Collections.Generic.ICollection<System.Collections.Generic.KeyValuePair<string, System.Text.Json.Nodes.JsonNode?>>, System.Collections.Generic.IDictionary<string, System.Text.Json.Nodes.JsonNode?>, System.Collections.Generic.IEnumerable<System.Collections.Generic.KeyValuePair<string, System.Text.Json.Nodes.JsonNode?>>, System.Collections.Generic.IList<System.Collections.Generic.KeyValuePair<string, System.Text.Json.Nodes.JsonNode?>>, System.Collections.IEnumerable
     {
         public JsonObject(System.Collections.Generic.IEnumerable<System.Collections.Generic.KeyValuePair<string, System.Text.Json.Nodes.JsonNode?>> properties, System.Text.Json.Nodes.JsonNodeOptions? options = default(System.Text.Json.Nodes.JsonNodeOptions?)) { }
         public JsonObject(System.Text.Json.Nodes.JsonNodeOptions? options = default(System.Text.Json.Nodes.JsonNodeOptions?)) { }
         public int Count { get { throw null; } }
         bool System.Collections.Generic.ICollection<System.Collections.Generic.KeyValuePair<string, System.Text.Json.Nodes.JsonNode?>>.IsReadOnly { get { throw null; } }
         System.Collections.Generic.ICollection<string> System.Collections.Generic.IDictionary<string, System.Text.Json.Nodes.JsonNode?>.Keys { get { throw null; } }
         System.Collections.Generic.ICollection<System.Text.Json.Nodes.JsonNode?> System.Collections.Generic.IDictionary<string, System.Text.Json.Nodes.JsonNode?>.Values { get { throw null; } }
+        System.Collections.Generic.KeyValuePair<string, System.Text.Json.Nodes.JsonNode?> System.Collections.Generic.IList<System.Collections.Generic.KeyValuePair<string, System.Text.Json.Nodes.JsonNode?>>.this[int index] { get { throw null; } set { } }
         public void Add(System.Collections.Generic.KeyValuePair<string, System.Text.Json.Nodes.JsonNode?> property) { }
         public void Add(string propertyName, System.Text.Json.Nodes.JsonNode? value) { }
         public void Clear() { }
         public bool ContainsKey(string propertyName) { throw null; }
         public static System.Text.Json.Nodes.JsonObject? Create(System.Text.Json.JsonElement element, System.Text.Json.Nodes.JsonNodeOptions? options = default(System.Text.Json.Nodes.JsonNodeOptions?)) { throw null; }
+        public System.Collections.Generic.KeyValuePair<string, System.Text.Json.Nodes.JsonNode?> GetAt(int index) { throw null; }
         public System.Collections.Generic.IEnumerator<System.Collections.Generic.KeyValuePair<string, System.Text.Json.Nodes.JsonNode?>> GetEnumerator() { throw null; }
+        public int IndexOf(string propertyName) { throw null; }
+        public void Insert(int index, string propertyName, System.Text.Json.Nodes.JsonNode? value) { }
         public bool Remove(string propertyName) { throw null; }
+        public void RemoveAt(int index) { }
+        public void SetAt(int index, string propertyName, System.Text.Json.Nodes.JsonNode? value) { }
+        public void SetAt(int index, System.Text.Json.Nodes.JsonNode? value) { }
         bool System.Collections.Generic.ICollection<System.Collections.Generic.KeyValuePair<string, System.Text.Json.Nodes.JsonNode?>>.Contains(System.Collections.Generic.KeyValuePair<string, System.Text.Json.Nodes.JsonNode> item) { throw null; }
         void System.Collections.Generic.ICollection<System.Collections.Generic.KeyValuePair<string, System.Text.Json.Nodes.JsonNode?>>.CopyTo(System.Collections.Generic.KeyValuePair<string, System.Text.Json.Nodes.JsonNode>[] array, int index) { }
         bool System.Collections.Generic.ICollection<System.Collections.Generic.KeyValuePair<string, System.Text.Json.Nodes.JsonNode?>>.Remove(System.Collections.Generic.KeyValuePair<string, System.Text.Json.Nodes.JsonNode> item) { throw null; }
-        bool System.Collections.Generic.IDictionary<string, System.Text.Json.Nodes.JsonNode?>.TryGetValue(string propertyName, out System.Text.Json.Nodes.JsonNode? jsonNode) { throw null; }
+        bool System.Collections.Generic.IDictionary<string, System.Text.Json.Nodes.JsonNode?>.TryGetValue(string propertyName, out System.Text.Json.Nodes.JsonNode jsonNode) { throw null; }
+        int System.Collections.Generic.IList<System.Collections.Generic.KeyValuePair<string, System.Text.Json.Nodes.JsonNode?>>.IndexOf(System.Collections.Generic.KeyValuePair<string, System.Text.Json.Nodes.JsonNode> item) { throw null; }
+        void System.Collections.Generic.IList<System.Collections.Generic.KeyValuePair<string, System.Text.Json.Nodes.JsonNode?>>.Insert(int index, System.Collections.Generic.KeyValuePair<string, System.Text.Json.Nodes.JsonNode> item) { }
+        void System.Collections.Generic.IList<System.Collections.Generic.KeyValuePair<string, System.Text.Json.Nodes.JsonNode?>>.RemoveAt(int index) { }
         System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator() { throw null; }
         public bool TryGetPropertyValue(string propertyName, out System.Text.Json.Nodes.JsonNode? jsonNode) { throw null; }
         public override void WriteTo(System.Text.Json.Utf8JsonWriter writer, System.Text.Json.JsonSerializerOptions? options = null) { }

src/libraries/System.Text.Json/src/System.Text.Json.csproj

@@ -72,9 +72,6 @@ The System.Text.Json library is built-in as part of the shared framework in .NET
     <Compile Include="System\Text\Json\JsonHelpers.cs" />
     <Compile Include="System\Text\Json\JsonHelpers.Date.cs" />
     <Compile Include="System\Text\Json\JsonHelpers.Escaping.cs" />
-    <Compile Include="System\Text\Json\JsonPropertyDictionary.cs" />
-    <Compile Include="System\Text\Json\JsonPropertyDictionary.KeyCollection.cs" />
-    <Compile Include="System\Text\Json\JsonPropertyDictionary.ValueCollection.cs" />
     <Compile Include="System\Text\Json\JsonTokenType.cs" />
     <Compile Include="System\Text\Json\Nodes\JsonArray.cs" />
     <Compile Include="System\Text\Json\Nodes\JsonArray.IList.cs" />
@@ -85,6 +82,7 @@ The System.Text.Json library is built-in as part of the shared framework in .NET
     <Compile Include="System\Text\Json\Nodes\JsonNodeOptions.cs" />
     <Compile Include="System\Text\Json\Nodes\JsonObject.cs" />
     <Compile Include="System\Text\Json\Nodes\JsonObject.IDictionary.cs" />
+    <Compile Include="System\Text\Json\Nodes\JsonObject.IList.cs" />
     <Compile Include="System\Text\Json\Nodes\JsonValue.CreateOverloads.cs" />
     <Compile Include="System\Text\Json\Nodes\JsonValue.cs" />
     <Compile Include="System\Text\Json\Nodes\JsonValueOfTCustomized.cs" />
@@ -354,6 +352,12 @@ The System.Text.Json library is built-in as part of the shared framework in .NET
     <Compile Include="$(CoreLibSharedDir)System\Reflection\NullabilityInfoContext.cs" />
   </ItemGroup>
 
+  <ItemGroup Condition="'$(TargetFrameworkIdentifier)' != '.NETCoreApp' or $([MSBuild]::VersionLessThan('$(TargetFrameworkVersion)', '9.0'))">
+    <Compile Include="System\Text\Json\OrderedDictionary.cs" />
+    <Compile Include="System\Text\Json\OrderedDictionary.KeyCollection.cs" />
+    <Compile Include="System\Text\Json\OrderedDictionary.ValueCollection.cs" />
+  </ItemGroup>
+
   <ItemGroup Condition="'$(TargetFrameworkIdentifier)' == '.NETCoreApp' and $([MSBuild]::VersionGreaterThanOrEquals('$(TargetFrameworkVersion)', '7.0'))">
     <Compile Include="System\Text\Json\Serialization\Converters\Value\Int128Converter.cs" />
     <Compile Include="System\Text\Json\Serialization\Converters\Value\UInt128Converter.cs" />
@@ -376,6 +380,12 @@ The System.Text.Json library is built-in as part of the shared framework in .NET
     <Compile Include="System\Text\Json\Reader\JsonReaderHelper.netstandard.cs" />
   </ItemGroup>
 
+  <ItemGroup>
+    <None Include="System\Text\Json\OrderedDictionary.cs" />
+    <None Include="System\Text\Json\OrderedDictionary.KeyCollection.cs" />
+    <None Include="System\Text\Json\OrderedDictionary.ValueCollection.cs" />
+  </ItemGroup>
+
   <!-- Application tfms (.NETCoreApp, .NETFramework) need to use the same or higher version of .NETStandard's dependencies. -->
   <ItemGroup>
     <ProjectReference Include="$(LibrariesProjectRoot)System.Text.Encodings.Web\src\System.Text.Encodings.Web.csproj" />