Fix #2035: Make the override modifier a link to the overridden member

The decompiled view only offered navigation on member names; finding
what an override actually overrides required opening the analyzer.
Attaching a reference to the modifier token gives the same
go-to-definition affordance Visual Studio has on 'override'. The
reference resolves via InheritanceHelper.GetBaseMember, so it targets
the nearest overridden member and degrades to plain text when the base
member cannot be resolved.

Assisted-by: Claude:claude-fable-5:Claude Code

ICSharpCode.Decompiler.Tests/ICSharpCode.Decompiler.Tests.csproj

@@ -147,6 +147,7 @@
     <Compile Include="Helpers\TestsAssemblyOutput.cs" />
     <Compile Include="Output\ILAmbienceTests.cs" />
     <Compile Include="Output\InsertParenthesesVisitorTests.cs" />
+    <Compile Include="Output\TextTokenWriterTests.cs" />
     <Compile Include="ProjectDecompiler\TargetFrameworkTests.cs" />
     <Compile Include="ProjectDecompiler\WholeProjectDecompilerTests.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />

ICSharpCode.Decompiler.Tests/Output/TextTokenWriterTests.cs

@@ -0,0 +1,130 @@
+// Copyright (c) 2026 Siegfried Pammer
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy of this
+// software and associated documentation files (the "Software"), to deal in the Software
+// without restriction, including without limitation the rights to use, copy, modify, merge,
+// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
+// to whom the Software is furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all copies or
+// substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
+// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Reflection.Metadata;
+
+using ICSharpCode.Decompiler.CSharp;
+using ICSharpCode.Decompiler.CSharp.OutputVisitor;
+using ICSharpCode.Decompiler.Disassembler;
+using ICSharpCode.Decompiler.Metadata;
+using ICSharpCode.Decompiler.TypeSystem;
+
+using NUnit.Framework;
+
+namespace ICSharpCode.Decompiler.Tests.Output
+{
+	// Sample hierarchy decompiled by the tests below. The members exercise the
+	// "override links to the overridden member" feature for methods and properties,
+	// including a second override level to pin down "nearest base member" semantics.
+	internal abstract class OverrideLinkBase
+	{
+		public abstract void Method();
+		public virtual int Property { get; set; }
+	}
+
+	internal class OverrideLinkDerived : OverrideLinkBase
+	{
+		public override void Method() { }
+		public override int Property { get; set; }
+	}
+
+	internal class OverrideLinkSecondLevel : OverrideLinkDerived
+	{
+		public override void Method() { }
+	}
+
+	[TestFixture]
+	public class TextTokenWriterTests
+	{
+		sealed class ReferenceRecordingOutput : ITextOutput
+		{
+			public readonly List<(string Text, IMember Member)> MemberReferences = new();
+
+			public string IndentationString { get; set; } = "\t";
+			public void Indent() { }
+			public void Unindent() { }
+			public void Write(char ch) { }
+			public void Write(string text) { }
+			public void WriteLine() { }
+			public void WriteReference(OpCodeInfo opCode, bool omitSuffix = false) { }
+			public void WriteReference(MetadataFile metadata, Handle handle, string text, string protocol = "decompile", bool isDefinition = false) { }
+			public void WriteReference(IType type, string text, bool isDefinition = false) { }
+
+			public void WriteReference(IMember member, string text, bool isDefinition = false)
+			{
+				if (!isDefinition)
+					MemberReferences.Add((text, member));
+			}
+
+			public void WriteLocalReference(string text, object reference, bool isDefinition = false) { }
+			public void MarkFoldStart(string collapsedText = "...", bool defaultCollapsed = false, bool isDefinition = false) { }
+			public void MarkFoldEnd() { }
+		}
+
+		static List<(string Text, IMember Member)> DecompileAndCollectMemberReferences(Type type)
+		{
+			string assemblyPath = typeof(TextTokenWriterTests).Assembly.Location;
+			using var module = new PEFile(assemblyPath);
+			var resolver = new UniversalAssemblyResolver(assemblyPath, false, module.Metadata.DetectTargetFrameworkId());
+			var settings = new DecompilerSettings();
+			var decompiler = new CSharpDecompiler(module, resolver, settings);
+			var syntaxTree = decompiler.DecompileType(new FullTypeName(type.FullName));
+
+			var output = new ReferenceRecordingOutput();
+			var tokenWriter = new TextTokenWriter(output, settings, decompiler.TypeSystem);
+			syntaxTree.AcceptVisitor(new CSharpOutputVisitor(tokenWriter, settings.CSharpFormattingOptions));
+			return output.MemberReferences;
+		}
+
+		static string FormatMember(IMember member) => $"{member.DeclaringType?.Name}.{member.Name}";
+
+		[Test]
+		public void OverrideKeywordReferencesTheOverriddenBaseMember()
+		{
+			var references = DecompileAndCollectMemberReferences(typeof(OverrideLinkDerived));
+
+			var overrideTargets = references.Where(r => r.Text == "override").Select(r => FormatMember(r.Member));
+			Assert.That(overrideTargets, Is.EquivalentTo(new[] {
+				"OverrideLinkBase.Method",
+				"OverrideLinkBase.Property",
+			}));
+		}
+
+		[Test]
+		public void OverrideKeywordReferencesTheNearestOverriddenMember()
+		{
+			var references = DecompileAndCollectMemberReferences(typeof(OverrideLinkSecondLevel));
+
+			var overrideTargets = references.Where(r => r.Text == "override").Select(r => FormatMember(r.Member));
+			Assert.That(overrideTargets, Is.EquivalentTo(new[] {
+				"OverrideLinkDerived.Method",
+			}));
+		}
+
+		[Test]
+		public void VirtualAndAbstractModifiersAreNotReferences()
+		{
+			var references = DecompileAndCollectMemberReferences(typeof(OverrideLinkBase));
+
+			Assert.That(references.Where(r => r.Text is "virtual" or "abstract" or "override"), Is.Empty);
+		}
+	}
+}

ICSharpCode.Decompiler/Output/TextTokenWriter.cs

@@ -240,6 +240,18 @@ namespace ICSharpCode.Decompiler
 					return;
 				}
 			}
+			// Make the 'override' modifier a reference to the nearest overridden member,
+			// so that go-to-definition on 'override' navigates to the base member.
+			// Modifier tokens are written without being pushed onto the node stack,
+			// so the top of the stack is the declaration the modifier belongs to.
+			if (role == EntityDeclaration.ModifierRole && keyword == "override"
+				&& nodeStack.Peek() is EntityDeclaration entityDeclaration
+				&& entityDeclaration.GetSymbol() is IMember { IsOverride: true } overrideMember
+				&& InheritanceHelper.GetBaseMember(overrideMember) is IMember baseMember)
+			{
+				output.WriteReference(baseMember, keyword);
+				return;
+			}
 			output.Write(keyword);
 		}