Add LanguageVersion for C# 13 (#74215)

docs/Language Feature Status.md

@@ -10,18 +10,24 @@ efforts behind them.
 
 | Feature | Branch | State | Developer | Reviewer | IDE Buddy | LDM Champ |
 | ------- | ------ | ----- | --------- | -------- | --------- | --------- |
+| [Overload Resolution Priority](https://github.com/dotnet/csharplang/issues/7706) | PR not yet available | [In Progress](https://github.com/dotnet/roslyn/issues/74131) | [333fred](https://github.com/333fred) | [jcouv](https://github.com/jcouv), [cston](https://github.com/cston) | Not yet assigned | [333fred](https://github.com/333fred) |
 | [First-class Span Types](https://github.com/dotnet/csharplang/issues/7905) | [FirstClassSpan](https://github.com/dotnet/roslyn/tree/features/FirstClassSpan) | [In Progress](https://github.com/dotnet/roslyn/issues/73445) | [jjonescz](https://github.com/jjonescz) | [cston](https://github.com/cston), [333fred](https://github.com/333fred) | | [333fred](https://github.com/333fred), [stephentoub](https://github.com/stephentoub) |
 | [Semi-auto-properties](https://github.com/dotnet/csharplang/issues/140) | [semi-auto-props](https://github.com/dotnet/roslyn/tree/features/semi-auto-props) | [In Progress](https://github.com/dotnet/roslyn/issues/57012) | [Youssef1313](https://github.com/Youssef1313) | [333fred](https://github.com/333fred), [RikkiGibson](https://github.com/RikkiGibson) | [CyrusNajmabadi](https://github.com/CyrusNajmabadi) | [CyrusNajmabadi](https://github.com/CyrusNajmabadi) |
 | [Default in deconstruction](https://github.com/dotnet/roslyn/pull/25562) | [decon-default](https://github.com/dotnet/roslyn/tree/features/decon-default) | [In Progress](https://github.com/dotnet/roslyn/issues/25559) | [jcouv](https://github.com/jcouv) | [gafter](https://github.com/gafter) |  | [jcouv](https://github.com/jcouv) |
 | [Roles/Extensions](https://github.com/dotnet/csharplang/issues/5497) | [roles](https://github.com/dotnet/roslyn/tree/features/roles) | [In Progress](https://github.com/dotnet/roslyn/issues/66722) | [jcouv](https://github.com/jcouv) | [AlekseyTs](https://github.com/AlekseyTs), [jjonescz](https://github.com/jjonescz) | [CyrusNajmabadi](https://github.com/CyrusNajmabadi) | [MadsTorgersen](https://github.com/MadsTorgersen) |
+| [Ref Struct Interfaces](https://github.com/dotnet/csharplang/issues/7608) | [RefStructInterfaces](https://github.com/dotnet/roslyn/tree/features/RefStructInterfaces) | [Merged into 17.11p2](https://github.com/dotnet/roslyn/issues/72124) | [AlekseyTs](https://github.com/AlekseyTs) | [cston](https://github.com/cston), [jjonescz](https://github.com/jjonescz) | [ToddGrun](https://github.com/ToddGrun) |  [agocke](https://github.com/agocke), [jaredpar](https://github.com/jaredpar) |
+
+# C# 13.0
+
+| Feature | Branch | State | Developer | Reviewer | IDE Buddy | LDM Champ |
+| ------- | ------ | ----- | --------- | -------- | --------- | --------- |
 | [Escape character](https://github.com/dotnet/csharplang/issues/7400) | N/A | [Merged into 17.9p1](https://github.com/dotnet/roslyn/pull/70497) | [CyrusNajmabadi](https://github.com/CyrusNajmabadi) | [jcouv](https://github.com/jcouv), [RikkiGibson](https://github.com/RikkiGibson) | (no IDE impact) | [CyrusNajmabadi](https://github.com/CyrusNajmabadi) | 
 | [Method group natural type improvements](https://github.com/dotnet/csharplang/blob/main/proposals/method-group-natural-type-improvements.md) | main | [Merged into 17.9p2](https://github.com/dotnet/roslyn/issues/69432) | [jcouv](https://github.com/jcouv) | [AlekseyTs](https://github.com/AlekseyTs), [cston](https://github.com/cston) | (no IDE impact) | [jcouv](https://github.com/jcouv) |
 | [`Lock` object](https://github.com/dotnet/csharplang/issues/7104) | [LockObject](https://github.com/dotnet/roslyn/tree/features/LockObject) | [Merged into 17.10p2](https://github.com/dotnet/roslyn/issues/71888) | [jjonescz](https://github.com/jjonescz) | [cston](https://github.com/cston), [RikkiGibson](https://github.com/RikkiGibson) | [CyrusNajmabadi](https://github.com/CyrusNajmabadi) (needs IDE fixer) | [stephentoub](https://github.com/stephentoub) |
 | Implicit indexer access in object initializers | main | [Merged into 17.9p3](https://github.com/dotnet/roslyn/pull/70649) | [jcouv](https://github.com/jcouv) | [AlekseyTs](https://github.com/AlekseyTs), [cston](https://github.com/cston) | (no IDE impact) |  |
 | [Params-collections](https://github.com/dotnet/csharplang/issues/7700) | main | [Merged to 17.10p3](https://github.com/dotnet/roslyn/issues/71137) | [AlekseyTs](https://github.com/AlekseyTs) | [RikkiGibson](https://github.com/RikkiGibson), [333fred](https://github.com/333fred) | [akhera99](https://github.com/akhera99) (needs IDE fixer) |  [MadsTorgersen](https://github.com/MadsTorgersen), [AlekseyTs](https://github.com/AlekseyTs) |
 | [Ref/unsafe in iterators/async](https://github.com/dotnet/csharplang/blob/main/proposals/ref-unsafe-in-iterators-async.md) | [RefInAsync](https://github.com/dotnet/roslyn/tree/features/RefInAsync) | [Merged into 17.11p2](https://github.com/dotnet/roslyn/issues/72662) | [jjonescz](https://github.com/jjonescz) | [AlekseyTs](https://github.com/AlekseyTs), [cston](https://github.com/cston) | (no IDE impact) | |
-| [Ref Struct Interfaces](https://github.com/dotnet/csharplang/issues/7608) | [RefStructInterfaces](https://github.com/dotnet/roslyn/tree/features/RefStructInterfaces) | [Merged into 17.11p2](https://github.com/dotnet/roslyn/issues/72124) | [AlekseyTs](https://github.com/AlekseyTs) | [cston](https://github.com/cston), [jjonescz](https://github.com/jjonescz) | [ToddGrun](https://github.com/ToddGrun) |  [agocke](https://github.com/agocke), [jaredpar](https://github.com/jaredpar) |
-| [Overload Resolution Priority](https://github.com/dotnet/csharplang/issues/7706) | PR not yet available | [In Progress](https://github.com/dotnet/roslyn/issues/74131) | [333fred](https://github.com/333fred) | [jcouv](https://github.com/jcouv), [cston](https://github.com/cston) | Not yet assigned | [333fred](https://github.com/333fred) |
+| [`allows ref struct` constraint](https://github.com/dotnet/csharplang/issues/7608) | [RefStructInterfaces](https://github.com/dotnet/roslyn/tree/features/RefStructInterfaces) | [Merged into 17.11p2](https://github.com/dotnet/roslyn/issues/72124) | [AlekseyTs](https://github.com/AlekseyTs) | [cston](https://github.com/cston), [jjonescz](https://github.com/jjonescz) | [ToddGrun](https://github.com/ToddGrun) |  [agocke](https://github.com/agocke), [jaredpar](https://github.com/jaredpar) |
 | [Partial properties](https://github.com/dotnet/csharplang/issues/6420) | [partial-properties](https://github.com/dotnet/roslyn/tree/features/partial-properties) | [Merged into 17.11p3](https://github.com/dotnet/roslyn/issues/73090) | [RikkiGibson](https://github.com/RikkiGibson) | [jcouv](https://github.com/jcouv), [333fred](https://github.com/333fred) | [Cosifne](https://github.com/Cosifne) | [333fred](https://github.com/333fred), [RikkiGibson](https://github.com/RikkiGibson) |
 
 # C# 12.0

src/Analyzers/CSharp/CodeFixes/UpgradeProject/CSharpUpgradeProjectCodeFixProvider.cs

@@ -60,6 +60,7 @@ public CSharpUpgradeProjectCodeFixProvider()
         "CS9058",
         "CS9194",
         "CS9202",
+        "CS9260",
     ];
 
     public override string UpgradeThisProjectResource => CSharpCodeFixesResources.Upgrade_this_project_to_csharp_language_version_0;

src/Compilers/CSharp/Portable/Binder/Binder_Expressions.cs

@@ -10448,7 +10448,7 @@ static bool isCandidateUnique(ref MethodSymbol? method, MethodSymbol candidate)
         /// </summary>
         private MethodSymbol? GetUniqueSignatureFromMethodGroup(BoundMethodGroup node)
         {
-            if (Compilation.LanguageVersion < LanguageVersionFacts.CSharpNext)
+            if (Compilation.LanguageVersion < LanguageVersion.CSharp13)
             {
                 return GetUniqueSignatureFromMethodGroup_CSharp10(node);
             }

src/Compilers/CSharp/Portable/CSharpResources.resx

@@ -6632,6 +6632,9 @@ To remove the warning, you can use /reference instead (set the Embed Interop Typ
   <data name="ERR_FeatureNotAvailableInVersion12" xml:space="preserve">
     <value>Feature '{0}' is not available in C# 12.0. Please use language version {1} or greater.</value>
   </data>
+  <data name="ERR_FeatureNotAvailableInVersion13" xml:space="preserve">
+    <value>Feature '{0}' is not available in C# 13.0. Please use language version {1} or greater.</value>
+  </data>
   <data name="ERR_UnexpectedArgumentList" xml:space="preserve">
     <value>Unexpected argument list.</value>
   </data>

src/Compilers/CSharp/Portable/Errors/ErrorCode.cs

@@ -2339,6 +2339,7 @@ internal enum ErrorCode
         INF_IdentifierConflictWithContextualKeyword = 9258,
 
         ERR_InlineArrayAttributeOnRecord = 9259,
+        ERR_FeatureNotAvailableInVersion13 = 9260,
 
         // Note: you will need to do the following after adding errors:
         //  1) Update ErrorFacts.IsBuildOnlyDiagnostic (src/Compilers/CSharp/Portable/Errors/ErrorFacts.cs)

src/Compilers/CSharp/Portable/Errors/ErrorFacts.cs

@@ -2451,6 +2451,7 @@ or ErrorCode.WRN_PartialPropertySignatureDifference
                 or ErrorCode.ERR_PartialPropertyRequiredDifference
                 or ErrorCode.INF_IdentifierConflictWithContextualKeyword
                 or ErrorCode.ERR_InlineArrayAttributeOnRecord
+                or ErrorCode.ERR_FeatureNotAvailableInVersion13
                     => false,
             };
 #pragma warning restore CS8524 // The switch expression does not handle some values of its input type (it is not exhaustive) involving an unnamed enum value.

src/Compilers/CSharp/Portable/Errors/MessageID.cs

@@ -471,16 +471,19 @@ internal static LanguageVersion RequiredVersion(this MessageID feature)
                 // PREFER reporting diagnostics in binding when diagnostics do not affect the shape of the syntax tree
 
                 // C# preview features.
-                case MessageID.IDS_FeatureStringEscapeCharacter:
+                case MessageID.IDS_FeatureRefStructInterfaces:
+                case MessageID.IDS_FeatureFieldAndValueKeywords:
+                    return LanguageVersion.Preview;
+
+                // C# 13.0 features.
+                case MessageID.IDS_FeatureStringEscapeCharacter: // lexer check
                 case MessageID.IDS_FeatureImplicitIndexerInitializer:
                 case MessageID.IDS_FeatureLockObject:
                 case MessageID.IDS_FeatureParamsCollections:
                 case MessageID.IDS_FeatureRefUnsafeInIteratorAsync:
-                case MessageID.IDS_FeatureRefStructInterfaces:
                 case MessageID.IDS_FeatureAllowsRefStructConstraint:
                 case MessageID.IDS_FeaturePartialProperties:
-                case MessageID.IDS_FeatureFieldAndValueKeywords:
-                    return LanguageVersion.Preview;
+                    return LanguageVersion.CSharp13;
 
                 // C# 12.0 features.
                 case MessageID.IDS_FeatureLambdaOptionalParameters: // semantic check

src/Compilers/CSharp/Portable/LanguageVersion.cs

@@ -231,6 +231,23 @@ public enum LanguageVersion
         /// </summary>
         CSharp12 = 1200,
 
+        /// <summary>
+        /// C# language version 13.0
+        /// <br/>
+        /// Features:
+        /// <list type="bullet">
+        /// <item><description>Escape character</description></item>
+        /// <item><description>Method group natural type improvements</description></item>
+        /// <item><description>`Lock` object</description></item>
+        /// <item><description>Implicit indexer access in object initializers</description></item>
+        /// <item><description>`params` collections</description></item>
+        /// <item><description>ref/unsafe in iterators/async</description></item>
+        /// <item><description>`allows ref struct` constraint</description></item>
+        /// <item><description>Partial properties</description></item>
+        /// </list>
+        /// </summary>
+        CSharp13 = 1300,
+
         /// <summary>
         /// The latest major supported version.
         /// </summary>
@@ -273,6 +290,7 @@ internal static bool IsValid(this LanguageVersion value)
                 case LanguageVersion.CSharp10:
                 case LanguageVersion.CSharp11:
                 case LanguageVersion.CSharp12:
+                case LanguageVersion.CSharp13:
                 case LanguageVersion.Preview:
                     return true;
             }
@@ -314,6 +332,8 @@ internal static ErrorCode GetErrorCode(this LanguageVersion version)
                     return ErrorCode.ERR_FeatureNotAvailableInVersion11;
                 case LanguageVersion.CSharp12:
                     return ErrorCode.ERR_FeatureNotAvailableInVersion12;
+                case LanguageVersion.CSharp13:
+                    return ErrorCode.ERR_FeatureNotAvailableInVersion13;
                 default:
                     throw ExceptionUtilities.UnexpectedValue(version);
             }
@@ -385,6 +405,8 @@ public static string ToDisplayString(this LanguageVersion version)
                     return "11.0";
                 case LanguageVersion.CSharp12:
                     return "12.0";
+                case LanguageVersion.CSharp13:
+                    return "13.0";
                 case LanguageVersion.Default:
                     return "default";
                 case LanguageVersion.Latest:
@@ -501,6 +523,11 @@ public static bool TryParse(string? version, out LanguageVersion result)
                     result = LanguageVersion.CSharp12;
                     return true;
 
+                case "13":
+                case "13.0":
+                    result = LanguageVersion.CSharp13;
+                    return true;
+
                 default:
                     result = LanguageVersion.Default;
                     return false;
@@ -517,13 +544,13 @@ public static LanguageVersion MapSpecifiedToEffectiveVersion(this LanguageVersio
                 case LanguageVersion.Latest:
                 case LanguageVersion.Default:
                 case LanguageVersion.LatestMajor:
-                    return LanguageVersion.CSharp12;
+                    return LanguageVersion.CSharp13;
                 default:
                     return version;
             }
         }
 
-        internal static LanguageVersion CurrentVersion => LanguageVersion.CSharp12;
+        internal static LanguageVersion CurrentVersion => LanguageVersion.CSharp13;
 
         /// <summary>Inference of tuple element names was added in C# 7.1</summary>
         internal static bool DisallowInferredTupleElementNames(this LanguageVersion self)

src/Compilers/CSharp/Portable/PublicAPI.Unshipped.txt

@@ -1,3 +1,4 @@
+Microsoft.CodeAnalysis.CSharp.LanguageVersion.CSharp13 = 1300 -> Microsoft.CodeAnalysis.CSharp.LanguageVersion
 [RSEXPERIMENTAL002]Microsoft.CodeAnalysis.CSharp.InterceptableLocation
 [RSEXPERIMENTAL002]abstract Microsoft.CodeAnalysis.CSharp.InterceptableLocation.Data.get -> string!
 [RSEXPERIMENTAL002]abstract Microsoft.CodeAnalysis.CSharp.InterceptableLocation.GetDisplayLocation() -> string!