Add DecompilerSettings.ExtensionMembers and Language version 14

Author: siegfriedpammer

ICSharpCode.Decompiler/CSharp/CSharpLanguageVersion.cs

@@ -36,7 +36,8 @@ public enum LanguageVersion
 		CSharp11_0 = 1100,
 		CSharp12_0 = 1200,
 		CSharp13_0 = 1300,
-		Preview = 1300,
+		CSharp14_0 = 1400,
+		Preview = 1400,
 		Latest = 0x7FFFFFFF
 	}
 }

ICSharpCode.Decompiler/DecompilerSettings.cs

@@ -171,10 +171,16 @@ public void SetLanguageVersion(CSharp.LanguageVersion languageVersion)
 			{
 				paramsCollections = false;
 			}
+			if (languageVersion < CSharp.LanguageVersion.CSharp14_0)
+			{
+				extensionMembers = false;
+			}
 		}
 
 		public CSharp.LanguageVersion GetMinimumRequiredVersion()
 		{
+			if (extensionMembers)
+				return CSharp.LanguageVersion.CSharp14_0;
 			if (paramsCollections)
 				return CSharp.LanguageVersion.CSharp13_0;
 			if (refReadOnlyParameters || usePrimaryConstructorSyntaxForNonRecordTypes || inlineArrays)
@@ -2117,6 +2123,24 @@ public bool InlineArrays {
 			}
 		}
 
+		bool extensionMembers = true;
+
+		/// <summary>
+		/// Gets/Sets whether C# 14.0 extension members should be transformed.
+		/// </summary>
+		[Category("C# 14.0 / VS 202x.yy")]
+		[Description("DecompilerSettings.ExtensionMembers")]
+		public bool ExtensionMembers {
+			get { return extensionMembers; }
+			set {
+				if (extensionMembers != value)
+				{
+					extensionMembers = value;
+					OnPropertyChanged();
+				}
+			}
+		}
+
 		bool separateLocalVariableDeclarations = false;
 
 		/// <summary>

ILSpy/Languages/CSharpLanguage.cs

@@ -117,6 +117,7 @@ public override IReadOnlyList<LanguageVersion> LanguageVersions {
 						new LanguageVersion(Decompiler.CSharp.LanguageVersion.CSharp11_0.ToString(), "C# 11.0 / VS 2022.4"),
 						new LanguageVersion(Decompiler.CSharp.LanguageVersion.CSharp12_0.ToString(), "C# 12.0 / VS 2022.8"),
 						new LanguageVersion(Decompiler.CSharp.LanguageVersion.CSharp13_0.ToString(), "C# 13.0 / VS 2022.12"),
+						new LanguageVersion(Decompiler.CSharp.LanguageVersion.CSharp14_0.ToString(), "C# 14.0 / VS 202x.yy"),
 					};
 				}
 				return versions;