From 11a84545c438d5fd9bb4c82d9aad1c551c483fd6 Mon Sep 17 00:00:00 2001
From: xtqqczze <45661989+xtqqczze@users.noreply.github.com>
Date: Tue, 14 Jul 2026 17:19:05 +0100
Subject: [PATCH] Remove dead net9 code

---
 .../src/System.Text.Json.csproj               |  2 +-
 .../Text/Json/Nodes/JsonObject.IDictionary.cs |  5 ----
 .../src/System/Text/Json/Nodes/JsonObject.cs  | 23 +------------------
 3 files changed, 2 insertions(+), 28 deletions(-)

diff --git a/src/libraries/System.Text.Json/src/System.Text.Json.csproj b/src/libraries/System.Text.Json/src/System.Text.Json.csproj
index 0a80a0e73974c8..ede6ef9a4172c3 100644
--- a/src/libraries/System.Text.Json/src/System.Text.Json.csproj
+++ b/src/libraries/System.Text.Json/src/System.Text.Json.csproj
@@ -392,7 +392,7 @@ The System.Text.Json library is built-in as part of the shared framework in .NET
     <Compile Include="$(CommonPath)Polyfills\StopwatchPolyfills.cs" Link="Common\Polyfills\StopwatchPolyfills.cs" />
   </ItemGroup>
 
-  <ItemGroup Condition="'$(TargetFrameworkIdentifier)' != '.NETCoreApp' or $([MSBuild]::VersionLessThan('$(TargetFrameworkVersion)', '9.0'))">
+  <ItemGroup Condition="'$(TargetFrameworkIdentifier)' != '.NETCoreApp'">
     <!-- Dependencies for System.Collections.Generic.OrderedDictionary -->
     <Compile Include="$(CoreLibSharedDir)System\Collections\HashHelpers.cs" Link="Common\System\Collections\HashHelpers.cs" />
     <Compile Include="$(CoreLibSharedDir)System\Collections\Generic\DebugViewDictionaryItem.cs" Link="Common\System\Collections\Generic\DebugViewDictionaryItem.cs" />
diff --git a/src/libraries/System.Text.Json/src/System/Text/Json/Nodes/JsonObject.IDictionary.cs b/src/libraries/System.Text.Json/src/System/Text/Json/Nodes/JsonObject.IDictionary.cs
index a16888ed3ecbb1..4d73bb3021e88c 100644
--- a/src/libraries/System.Text.Json/src/System/Text/Json/Nodes/JsonObject.IDictionary.cs
+++ b/src/libraries/System.Text.Json/src/System/Text/Json/Nodes/JsonObject.IDictionary.cs
@@ -58,12 +58,7 @@ public bool TryAdd(string propertyName, JsonNode? value, out int index)
             {
                 ThrowHelper.ThrowArgumentNullException(nameof(propertyName));
             }
-#if NET9_0
-            bool success = Dictionary.TryAdd(propertyName, value);
-            index = success ? Dictionary.Count - 1 : Dictionary.IndexOf(propertyName);
-#else
             bool success = Dictionary.TryAdd(propertyName, value, out index);
-#endif
             if (success)
             {
                 value?.AssignParent(this);
diff --git a/src/libraries/System.Text.Json/src/System/Text/Json/Nodes/JsonObject.cs b/src/libraries/System.Text.Json/src/System/Text/Json/Nodes/JsonObject.cs
index 5ded130cff70ca..07fac1d7ca2550 100644
--- a/src/libraries/System.Text.Json/src/System/Text/Json/Nodes/JsonObject.cs
+++ b/src/libraries/System.Text.Json/src/System/Text/Json/Nodes/JsonObject.cs
@@ -142,19 +142,7 @@ public bool TryGetPropertyValue(string propertyName, out JsonNode? jsonNode, out
         {
             ArgumentNullException.ThrowIfNull(propertyName);
 
-#if NET9_0
-            index = Dictionary.IndexOf(propertyName);
-            if (index < 0)
-            {
-                jsonNode = null;
-                return false;
-            }
-
-            jsonNode = Dictionary.GetAt(index).Value;
-            return true;
-#else
             return Dictionary.TryGetValue(propertyName, out jsonNode, out index);
-#endif
         }
 
         /// <inheritdoc/>
@@ -287,17 +275,8 @@ internal void SetItem(string propertyName, JsonNode? value)
 
             OrderedDictionary<string, JsonNode?> dict = Dictionary;
 
-            if (
-#if NET9_0
-                !dict.TryAdd(propertyName, value)
-#else
-                !dict.TryAdd(propertyName, value, out int index)
-#endif
-                )
+            if (!dict.TryAdd(propertyName, value, out int index))
             {
-#if NET9_0
-                int index = dict.IndexOf(propertyName);
-#endif
                 Debug.Assert(index >= 0);
                 JsonNode? replacedValue = dict.GetAt(index).Value;