Task 38349: Set LangVersion to 13 for all targets (#3588)

- Explicitly setting C# language version to 13 for all targets.
- Adding IDisposable to ref structs where appropriate.

Author: paulmedynski

src/Directory.Build.props

@@ -113,23 +113,20 @@
   </PropertyGroup>
 
   <!--
-    For non-.NET, we explicitly set the C# language version to 13.  This matches
-    the language version used by the .NET 9 SDK, and provides helpful modern
-    language features.  While this isn't strictly supported by .NET in general,
-    it works well in practice.  There are very few C# language features that
-    depend on SDK APIs, and we avoid them.
+    We want to use the latest C# language regardless of target framework,
+    so we explicitly set LangVersion for all targets.
 
-    For .NET, we omit this property entirely, which results in the SDK choosing
-    the C# language version that matches the .NET version.
+    We will roll this version forward as new C# language versions are released
+    and associated with the newest .NET SDK we support.
 
     Details here:
 
     https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/language-versioning
 
     https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/configure-language-version
   -->
-  <PropertyGroup
-    Condition="'$([MSBuild]::GetTargetFrameworkIdentifier($(TargetFramework)))' != '.NETCoreApp'">
-    <LangVersion>13.0</LangVersion>
+  <PropertyGroup>
+    <!-- The newest .NET SDK we support is .NET 9.0, which uses C# 13 -->
+    <LangVersion>13</LangVersion>
   </PropertyGroup>
 </Project>

src/Microsoft.Data.SqlClient/src/Microsoft/Data/Common/AdapterUtil.cs

@@ -1497,23 +1497,23 @@ internal static Exception NumericToDecimalOverflow()
         }
 
         //
-        // : IDbCommand
+        // IDbCommand
         //
         internal static Exception InvalidCommandTimeout(int value, string name)
         {
             return Argument(StringsHelper.GetString(Strings.ADP_InvalidCommandTimeout, value.ToString(CultureInfo.InvariantCulture)), name);
         }
 
         //
-        // : DbDataAdapter
+        // DbDataAdapter
         //
         internal static InvalidOperationException ComputerNameEx(int lastError)
         {
             return InvalidOperation(StringsHelper.GetString(Strings.ADP_ComputerNameEx, lastError));
         }
 
         //
-        // : SNI
+        // SNI
         //
         internal static PlatformNotSupportedException SNIPlatformNotSupported(string platform) => new(StringsHelper.GetString(Strings.SNI_PlatformNotSupportedNetFx, platform));
 
@@ -1635,7 +1635,7 @@ internal static ArgumentOutOfRangeException InvalidParameterDirection(ParameterD
         }
 
         //
-        // : IDbCommand
+        // IDbCommand
         //
         internal static Exception InvalidCommandTimeout(int value, [CallerMemberName] string property = "")
             => Argument(StringsHelper.GetString(Strings.ADP_InvalidCommandTimeout, value.ToString(CultureInfo.InvariantCulture)), property);

src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/Diagnostics/DiagnosticScope.netcore.cs

@@ -9,7 +9,7 @@
 
 namespace Microsoft.Data.SqlClient.Diagnostics
 {
-    internal ref struct DiagnosticScope //: IDisposable
+    internal ref struct DiagnosticScope : IDisposable
     {
         private const int CommandOperation = 1;
         private const int ConnectionOpenOperation = 2;

src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/Diagnostics/DiagnosticTransactionScope.netcore.cs

@@ -10,7 +10,7 @@
 
 namespace Microsoft.Data.SqlClient.Diagnostics
 {
-    internal ref struct DiagnosticTransactionScope //: IDisposable
+    internal ref struct DiagnosticTransactionScope : IDisposable
     {
         public const int TransactionCommit = 1;
         public const int TransactionRollback = 2;

src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/SqlClientEventSource.cs

@@ -1139,7 +1139,7 @@ public static TrySNIEventScope Create(string className, [System.Runtime.Compiler
             => new TrySNIEventScope(SqlClientEventSource.Log.TrySNIScopeEnterEvent(className, memberName));
     }
 
-    internal readonly ref struct TryEventScope //: IDisposable
+    internal readonly ref struct TryEventScope : IDisposable
     {
         private readonly long _scopeId;
 

src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/SqlStatistics.cs

@@ -341,7 +341,7 @@ void ICollection.CopyTo(Array array, int arrayIndex)
     // This is a ref struct to prevent it being included in async closures accidentally. 
     // Async functions should manage the timer directly using the Start and Stop method
     // in their invoke and completion functions
-    internal readonly ref struct ValueSqlStatisticsScope // : IDisposable // ref structs cannot implement interfaces but the compiler will use pattern matching to allow use of using on them
+    internal readonly ref struct ValueSqlStatisticsScope : IDisposable
     {
         private readonly SqlStatistics _statistics;
 

src/Microsoft.Data.SqlClient/tests/ManualTests/DataCommon/DataTestUtility.cs

@@ -1216,7 +1216,7 @@ protected virtual void OnMatchingEventWritten(EventWrittenEventArgs eventData)
             }
         }
 
-        public readonly ref struct XEventScope // : IDisposable
+        public readonly ref struct XEventScope : IDisposable
         {
             private const int MaxXEventsLatencyS = 5;