Add per language options to disable GoToDef and GoToImpl.

src/EditorFeatures/Core/EditorFeatures.csproj

@@ -109,6 +109,8 @@
     <Compile Include="FindUsages\IFindUsagesContext.cs" />
     <Compile Include="FindUsages\IFindUsagesService.cs" />
     <Compile Include="FindUsages\SimpleFindUsagesContext.cs" />
+    <Compile Include="GoToDefinition\GoToDefinitionOptions.cs" />
+    <Compile Include="GoToImplementation\GoToImplementationOptions.cs" />
     <Compile Include="Tags\ExportImageMonikerServiceAttribute.cs" />
     <Compile Include="Implementation\NavigateTo\AbstractNavigateToItemDisplay.cs" />
     <Compile Include="CommandArgs.cs" />

src/EditorFeatures/Core/GoToDefinition/GoToDefinitionCommandHandler.cs

@@ -27,15 +27,21 @@ internal class GoToDefinitionCommandHandler :
 
         public CommandState GetCommandState(GoToDefinitionCommandArgs args, Func<CommandState> nextHandler)
         {
-            return CommandState.Available;
+            return args.SubjectBuffer.GetFeatureOnOffOption(GoToDefinitionOptions.Enabled)
+                ? CommandState.Available
+                : CommandState.Unavailable;
         }
 
         public void ExecuteCommand(GoToDefinitionCommandArgs args, Action nextHandler)
         {
-            var caretPos = args.TextView.GetCaretPoint(args.SubjectBuffer);
-            if (caretPos.HasValue && TryExecuteCommand(args.SubjectBuffer.CurrentSnapshot, caretPos.Value))
+            var subjectBuffer = args.SubjectBuffer;
+            if (subjectBuffer.GetFeatureOnOffOption(GoToDefinitionOptions.Enabled))
             {
-                return;
+                var caretPos = args.TextView.GetCaretPoint(subjectBuffer);
+                if (caretPos.HasValue && TryExecuteCommand(subjectBuffer.CurrentSnapshot, caretPos.Value))
+                {
+                    return;
+                }
             }
 
             nextHandler();

src/EditorFeatures/Core/GoToDefinition/GoToDefinitionOptions.cs

+// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+using Microsoft.CodeAnalysis.Options;
+
+namespace Microsoft.CodeAnalysis.Editor
+{
+    internal static class GoToDefinitionOptions
+    {
+        public static readonly PerLanguageOption<bool> Enabled = new PerLanguageOption<bool>(
+            nameof(GoToDefinitionOptions), nameof(Enabled), defaultValue: true);
+    }
+}

src/EditorFeatures/Core/GoToDefinition/IGoToDefinitionService.cs

@@ -5,6 +5,7 @@
 using System.Threading.Tasks;
 using Microsoft.CodeAnalysis.Host;
 using Microsoft.CodeAnalysis.Navigation;
+using Microsoft.CodeAnalysis.Options;
 
 namespace Microsoft.CodeAnalysis.Editor
 {

src/EditorFeatures/Core/GoToImplementation/GoToImplementationCommandHandler.cs

@@ -34,21 +34,27 @@ internal partial class GoToImplementationCommandHandler : ICommandHandler<GoToIm
 
         public CommandState GetCommandState(GoToImplementationCommandArgs args, Func<CommandState> nextHandler)
         {
-            // Because this is expensive to compute, we just always say yes
-            return CommandState.Available;
+            // Because this is expensive to compute, we just always say yes as long as the language allows it.
+            return args.SubjectBuffer.GetFeatureOnOffOption(GoToImplementationOptions.Enabled)
+                ? CommandState.Available
+                : CommandState.Unavailable;
         }
 
         public void ExecuteCommand(GoToImplementationCommandArgs args, Action nextHandler)
         {
-            var caret = args.TextView.GetCaretPoint(args.SubjectBuffer);
+            var subjectBuffer = args.SubjectBuffer;
 
-            if (caret.HasValue)
+            if (subjectBuffer.GetFeatureOnOffOption(GoToImplementationOptions.Enabled))
             {
-                var document = args.SubjectBuffer.CurrentSnapshot.GetOpenDocumentInCurrentContextWithChanges();
-                if (document != null)
+                var caret = args.TextView.GetCaretPoint(subjectBuffer);
+                if (caret.HasValue)
                 {
-                    ExecuteCommand(document, caret.Value);
-                    return;
+                    var document = subjectBuffer.CurrentSnapshot.GetOpenDocumentInCurrentContextWithChanges();
+                    if (document != null)
+                    {
+                        ExecuteCommand(document, caret.Value);
+                        return;
+                    }
                 }
             }
 

src/EditorFeatures/Core/GoToImplementation/GoToImplementationOptions.cs

+// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+using Microsoft.CodeAnalysis.Options;
+
+namespace Microsoft.CodeAnalysis.Editor.GoToImplementation
+{
+    internal static class GoToImplementationOptions
+    {
+        public static readonly PerLanguageOption<bool> Enabled = new PerLanguageOption<bool>(
+            nameof(GoToImplementationOptions), nameof(Enabled), defaultValue: true);
+    }
+}
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