Add trim annotations to System.Configuration.ConfigurationManager

src/libraries/System.Configuration.ConfigurationManager/src/ILLink/ILLink.Suppressions.xml

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="utf-8"?>
+<linker>
+  <assembly fullname="System.Configuration.ConfigurationManager, Version=10.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51">
+    <attribute fullname="System.Diagnostics.CodeAnalysis.UnconditionalSuppressMessageAttribute">
+      <argument>ILLink</argument>
+      <argument>IL2026</argument>
+      <property name="Scope">type</property>
+      <property name="Target">T:System.Configuration.BaseConfigurationRecord</property>
+    </attribute>
+    <attribute fullname="System.Diagnostics.CodeAnalysis.UnconditionalSuppressMessageAttribute">
+      <argument>ILLink</argument>
+      <argument>IL2026</argument>
+      <property name="Scope">type</property>
+      <property name="Target">T:System.Configuration.ConfigurationElementCollection</property>
+    </attribute>
+  </assembly>
+</linker>

src/libraries/System.Configuration.ConfigurationManager/src/System.Configuration.ConfigurationManager.csproj

@@ -3,8 +3,6 @@
   <PropertyGroup>
     <TargetFrameworks>$(NetCoreAppCurrent);$(NetCoreAppPrevious);$(NetCoreAppMinimum);netstandard2.0;$(NetFrameworkMinimum)</TargetFrameworks>
     <NoWarn>$(NoWarn);CA2249</NoWarn>
-    <!-- opt-out of trimming until it works https://github.com/dotnet/runtime/issues/49062 -->
-    <IsTrimmable>false</IsTrimmable>
     <EnableAOTAnalyzer>false</EnableAOTAnalyzer>
     <IncludeInternalObsoleteAttribute>true</IncludeInternalObsoleteAttribute>
     <UseCompilerGeneratedDocXmlFile>false</UseCompilerGeneratedDocXmlFile>
@@ -295,4 +293,11 @@
     <Reference Include="System.Configuration" />
   </ItemGroup>
 
+  <ItemGroup Condition="'$(TargetFrameworkIdentifier)' != '.NETCoreApp'">
+    <Compile Include="$(CoreLibSharedDir)System\Diagnostics\CodeAnalysis\DynamicallyAccessedMembersAttribute.cs" />
+    <Compile Include="$(CoreLibSharedDir)System\Diagnostics\CodeAnalysis\DynamicallyAccessedMemberTypes.cs" />
+    <Compile Include="$(CoreLibSharedDir)System\Diagnostics\CodeAnalysis\RequiresDynamicCodeAttribute.cs" />
+    <Compile Include="$(CoreLibSharedDir)System\Diagnostics\CodeAnalysis\RequiresUnreferencedCodeAttribute.cs" />
+  </ItemGroup>
+
 </Project>

src/libraries/System.Configuration.ConfigurationManager/src/System/Configuration/AppSettingsReader.cs

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System.Collections.Specialized;
+using System.Diagnostics.CodeAnalysis;
 using System.Globalization;
 
 namespace System.Configuration
@@ -16,6 +17,7 @@ public class AppSettingsReader
         private static readonly Type s_stringType = typeof(string);
         private const string NullString = "None";
 
+        [RequiresUnreferencedCode(ConfigurationManager.TrimWarning)]
         public AppSettingsReader()
         {
             _map = System.Configuration.ConfigurationManager.AppSettings;

src/libraries/System.Configuration.ConfigurationManager/src/System/Configuration/AppSettingsSection.cs

@@ -2,11 +2,13 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System.Collections.Specialized;
+using System.Diagnostics.CodeAnalysis;
 using System.IO;
 using System.Xml;
 
 namespace System.Configuration
 {
+    [RequiresUnreferencedCode(ConfigurationManager.TrimWarning)]
     public sealed class AppSettingsSection : ConfigurationSection
     {
         private static volatile ConfigurationPropertyCollection s_properties;
@@ -25,9 +27,13 @@ public AppSettingsSection()
         internal NameValueCollection InternalSettings
             => _keyValueCollection ??= new KeyValueInternalCollection(this);
 
+        [UnconditionalSuppressMessage("ReflectionAnalysis", "IL2026:RequiresUnreferencedCodeMessage",
+            Justification = "Reflection access to the ConfigurationPropertyAttribute instance is covered by RequiresUnreferencedCode on the class: https://github.com/dotnet/runtime/issues/108454")]
         [ConfigurationProperty("", IsDefaultCollection = true)]
         public KeyValueConfigurationCollection Settings => (KeyValueConfigurationCollection)base[s_propAppSettings];
 
+        [UnconditionalSuppressMessage("ReflectionAnalysis", "IL2026:RequiresUnreferencedCodeMessage",
+            Justification = "Reflection access to the ConfigurationPropertyAttribute instance is covered by RequiresUnreferencedCode on the class: https://github.com/dotnet/runtime/issues/108454")]
         [ConfigurationProperty("file", DefaultValue = "")]
         public string File
         {

src/libraries/System.Configuration.ConfigurationManager/src/System/Configuration/ApplicationSettingsBase.cs

@@ -4,13 +4,15 @@
 using System.Collections.Generic;
 using System.ComponentModel;
 using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
 using System.Reflection;
 
 namespace System.Configuration
 {
     /// <summary>
     /// Base settings class for client applications.
     /// </summary>
+    [RequiresUnreferencedCode(ConfigurationManager.TrimWarning)]
     public abstract class ApplicationSettingsBase : SettingsBase, INotifyPropertyChanged
     {
         private bool _explicitSerializeOnClass;

src/libraries/System.Configuration.ConfigurationManager/src/System/Configuration/BaseConfigurationRecord.cs

@@ -7,6 +7,7 @@
 using System.Collections.Specialized;
 using System.Configuration.Internal;
 using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
 using System.IO;
 using System.Runtime.Versioning;
 using System.Text;
@@ -17,6 +18,7 @@ namespace System.Configuration
 {
     // This object represents the configuration for a request path, and is cached per-path.
     [DebuggerDisplay("ConfigPath = {ConfigPath}")]
+    [RequiresUnreferencedCode(ConfigurationManager.TrimWarning)]
     internal abstract class BaseConfigurationRecord : IInternalConfigRecord
     {
 #if NET8_0_OR_GREATER

src/libraries/System.Configuration.ConfigurationManager/src/System/Configuration/CallbackValidatorAttribute.cs

@@ -1,6 +1,7 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System.Diagnostics.CodeAnalysis;
 using System.Reflection;
 
 namespace System.Configuration
@@ -10,6 +11,8 @@ public sealed class CallbackValidatorAttribute : ConfigurationValidatorAttribute
     {
         private ValidatorCallback _callbackMethod;
         private string _callbackMethodName = string.Empty;
+
+        [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicMethods)]
         private Type _type;
 
         public override ConfigurationValidatorBase ValidatorInstance
@@ -42,6 +45,7 @@ public override ConfigurationValidatorBase ValidatorInstance
             }
         }
 
+        [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicMethods)]
         public Type Type
         {
             get { return _type; }

src/libraries/System.Configuration.ConfigurationManager/src/System/Configuration/ClientConfigurationHost.cs

@@ -3,6 +3,7 @@
 
 using System.Configuration.Internal;
 using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
 using System.IO;
 using System.Net;
 using System.Runtime.InteropServices;
@@ -32,6 +33,7 @@ internal sealed class ClientConfigurationHost : DelegatingConfigHost, IInternalC
         private ExeConfigurationFileMap _fileMap; // optional file map
         private bool _initComplete;
 
+        [RequiresUnreferencedCode(ConfigurationManager.TrimWarning)]
         internal ClientConfigurationHost()
         {
             Host = new InternalConfigHost();
@@ -423,6 +425,7 @@ private static ConfigurationUserLevel GetUserLevel(string configPath)
             return level;
         }
 
+        [RequiresUnreferencedCode(ConfigurationManager.TrimWarning)]
         internal static Configuration OpenExeConfiguration(ConfigurationFileMap fileMap, bool isMachine,
             ConfigurationUserLevel userLevel, string exePath)
         {

src/libraries/System.Configuration.ConfigurationManager/src/System/Configuration/ClientConfigurationSystem.cs

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System.Configuration.Internal;
+using System.Diagnostics.CodeAnalysis;
 using System.Threading;
 
 namespace System.Configuration
@@ -21,6 +22,7 @@ internal sealed class ClientConfigurationSystem : IInternalConfigSystem
         private bool _isUserConfigInited;
         private IInternalConfigRecord _machineConfigRecord;
 
+        [RequiresUnreferencedCode(ConfigurationManager.TrimWarning)]
         internal ClientConfigurationSystem()
         {
             IConfigSystem configSystem = new ConfigSystem();

src/libraries/System.Configuration.ConfigurationManager/src/System/Configuration/ClientSettingsSection.cs

@@ -1,11 +1,14 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System.Diagnostics.CodeAnalysis;
+
 namespace System.Configuration
 {
     /// <summary>
     /// ConfigurationSection class for sections that store client settings.
     /// </summary>
+    [RequiresUnreferencedCode(ConfigurationManager.TrimWarning)]
     public sealed class ClientSettingsSection : ConfigurationSection
     {
         private static readonly ConfigurationProperty s_propSettings = new ConfigurationProperty(null, typeof(SettingElementCollection), null, ConfigurationPropertyOptions.IsDefaultCollection);
@@ -23,6 +26,8 @@ protected internal override ConfigurationPropertyCollection Properties
             }
         }
 
+        [UnconditionalSuppressMessage("ReflectionAnalysis", "IL2026:RequiresUnreferencedCodeMessage",
+            Justification = "Reflection access to the ConfigurationPropertyAttribute instance is covered by RequiresUnreferencedCode on the class: https://github.com/dotnet/runtime/issues/108454")]
         [ConfigurationProperty("", IsDefaultCollection = true)]
         public SettingElementCollection Settings
         {

src/libraries/System.Configuration.ConfigurationManager/src/System/Configuration/ClientSettingsStore.cs

@@ -4,6 +4,7 @@
 using System.Collections;
 using System.Configuration.Internal;
 using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
 using System.IO;
 using System.Xml;
 
@@ -24,6 +25,7 @@ internal sealed class ClientSettingsStore
         private const string ApplicationSettingsGroupPrefix = ApplicationSettingsGroupName + "/";
         private const string UserSettingsGroupPrefix = UserSettingsGroupName + "/";
 
+        [RequiresUnreferencedCode(ConfigurationManager.TrimWarning)]
         private static Configuration GetUserConfig(bool isRoaming)
         {
             ConfigurationUserLevel userLevel = isRoaming ? ConfigurationUserLevel.PerUserRoaming :
@@ -32,6 +34,7 @@ private static Configuration GetUserConfig(bool isRoaming)
             return ClientSettingsConfigurationHost.OpenExeConfiguration(userLevel);
         }
 
+        [RequiresUnreferencedCode(ConfigurationManager.TrimWarning)]
         private static ClientSettingsSection GetConfigSection(Configuration config, string sectionName, bool declare)
         {
             string fullSectionName = UserSettingsGroupPrefix + sectionName;
@@ -54,6 +57,7 @@ private static ClientSettingsSection GetConfigSection(Configuration config, stri
 
         // Declares the section handler of a given section in its section group, if a declaration isn't already
         // present.
+        [RequiresUnreferencedCode(ConfigurationManager.TrimWarning)]
         private static void DeclareSection(Configuration config, string sectionName)
         {
             ConfigurationSectionGroup settingsGroup = config.GetSectionGroup(UserSettingsGroupName);
@@ -82,6 +86,7 @@ private static void DeclareSection(Configuration config, string sectionName)
             }
         }
 
+        [RequiresUnreferencedCode(ConfigurationManager.TrimWarning)]
         internal static IDictionary ReadSettings(string sectionName, bool isUserScoped)
         {
             Hashtable settings = new Hashtable();
@@ -106,6 +111,7 @@ internal static IDictionary ReadSettings(string sectionName, bool isUserScoped)
             return settings;
         }
 
+        [RequiresUnreferencedCode(ConfigurationManager.TrimWarning)]
         internal static IDictionary ReadSettingsFromFile(string configFileName, string sectionName, bool isUserScoped)
         {
             Hashtable settings = new Hashtable();
@@ -146,11 +152,13 @@ internal static IDictionary ReadSettingsFromFile(string configFileName, string s
             return settings;
         }
 
+        [RequiresUnreferencedCode(ConfigurationManager.TrimWarning)]
         internal static ConnectionStringSettingsCollection ReadConnectionStrings()
         {
             return PrivilegedConfigurationManager.ConnectionStrings;
         }
 
+        [RequiresUnreferencedCode(ConfigurationManager.TrimWarning)]
         internal static void RevertToParent(string sectionName, bool isRoaming)
         {
             if (!ConfigurationManagerInternalFactory.Instance.SupportsUserConfig)
@@ -169,6 +177,7 @@ internal static void RevertToParent(string sectionName, bool isRoaming)
             }
         }
 
+        [RequiresUnreferencedCode(ConfigurationManager.TrimWarning)]
         internal static void WriteSettings(string sectionName, bool isRoaming, IDictionary newSettings)
         {
             if (!ConfigurationManagerInternalFactory.Instance.SupportsUserConfig)
@@ -218,6 +227,7 @@ internal static void WriteSettings(string sectionName, bool isRoaming, IDictiona
         /// A private configuration host that we use to write settings to config. We need this so we
         /// can enforce a quota on the size of stuff written out.
         /// </summary>
+        [RequiresUnreferencedCode(ConfigurationManager.TrimWarning)]
         private sealed class ClientSettingsConfigurationHost : DelegatingConfigHost
         {
             private const string ClientConfigurationHostTypeName = "System.Configuration.ClientConfigurationHost, " + TypeUtil.ConfigurationManagerAssemblyName;

src/libraries/System.Configuration.ConfigurationManager/src/System/Configuration/ConfigDefinitionUpdates.cs

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System.Collections;
+using System.Diagnostics.CodeAnalysis;
 
 namespace System.Configuration
 {
@@ -29,6 +30,7 @@ internal LocationUpdates FindLocationUpdates(OverrideModeSetting overrideMode, b
         }
 
         // Add a section definition update to the correct location update.
+        [RequiresUnreferencedCode(ConfigurationManager.TrimWarning)]
         internal DefinitionUpdate AddUpdate(OverrideModeSetting overrideMode, bool inheritInChildApps, bool moved,
             string updatedXml, SectionRecord sectionRecord)
         {