Have distinct messages for adding vs. removing accessibility modifiers (#77188)

Author: CyrusNajmabadi

src/Analyzers/CSharp/Analyzers/AddAccessibilityModifiers/CSharpAddAccessibilityModifiersDiagnosticAnalyzer.cs

@@ -2,21 +2,22 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
-using System.Collections.Immutable;
 using Microsoft.CodeAnalysis.AddAccessibilityModifiers;
 using Microsoft.CodeAnalysis.CodeStyle;
-using Microsoft.CodeAnalysis.CSharp.Extensions;
 using Microsoft.CodeAnalysis.CSharp.LanguageService;
 using Microsoft.CodeAnalysis.CSharp.Syntax;
 using Microsoft.CodeAnalysis.Diagnostics;
-using Microsoft.CodeAnalysis.Shared.Extensions;
+using Microsoft.CodeAnalysis.LanguageService;
 
 namespace Microsoft.CodeAnalysis.CSharp.AddAccessibilityModifiers;
 
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
-internal class CSharpAddAccessibilityModifiersDiagnosticAnalyzer
+internal sealed class CSharpAddAccessibilityModifiersDiagnosticAnalyzer
     : AbstractAddAccessibilityModifiersDiagnosticAnalyzer<CompilationUnitSyntax>
 {
+    protected override IAccessibilityFacts AccessibilityFacts => CSharpAccessibilityFacts.Instance;
+    protected override IAddAccessibilityModifiers AddAccessibilityModifiers => CSharpAddAccessibilityModifiers.Instance;
+
     protected override void ProcessCompilationUnit(
         SyntaxTreeAnalysisContext context,
         CodeStyleOption2<AccessibilityModifiersRequired> option, CompilationUnitSyntax compilationUnit)
@@ -47,20 +48,6 @@ private void ProcessMemberDeclaration(
         if (member is TypeDeclarationSyntax typeDeclaration)
             ProcessMembers(context, option, typeDeclaration.Members);
 
-        if (!CSharpAddAccessibilityModifiers.Instance.ShouldUpdateAccessibilityModifier(
-                CSharpAccessibilityFacts.Instance, member, option.Value, out var name, out var modifiersAdded))
-        {
-            return;
-        }
-
-        // Have an issue to flag, either add or remove. Report issue to user.
-        var additionalLocations = ImmutableArray.Create(member.GetLocation());
-        context.ReportDiagnostic(DiagnosticHelper.Create(
-            Descriptor,
-            name.GetLocation(),
-            option.Notification,
-            context.Options,
-            additionalLocations: additionalLocations,
-            modifiersAdded ? ModifiersAddedProperties : null));
+        CheckMemberAndReportDiagnostic(context, option, member);
     }
 }

src/Analyzers/Core/Analyzers/AddAccessibilityModifiers/AbstractAddAccessibilityModifiersDiagnosticAnalyzer.cs

@@ -5,6 +5,7 @@
 using System.Collections.Immutable;
 using Microsoft.CodeAnalysis.CodeStyle;
 using Microsoft.CodeAnalysis.Diagnostics;
+using Microsoft.CodeAnalysis.LanguageService;
 
 namespace Microsoft.CodeAnalysis.AddAccessibilityModifiers;
 
@@ -17,6 +18,18 @@ internal abstract class AbstractAddAccessibilityModifiersDiagnosticAnalyzer<TCom
         new LocalizableResourceString(nameof(AnalyzersResources.Accessibility_modifiers_required), AnalyzersResources.ResourceManager, typeof(AnalyzersResources)))
     where TCompilationUnitSyntax : SyntaxNode
 {
+    protected abstract IAccessibilityFacts AccessibilityFacts { get; }
+    protected abstract IAddAccessibilityModifiers AddAccessibilityModifiers { get; }
+
+    protected abstract void ProcessCompilationUnit(SyntaxTreeAnalysisContext context, CodeStyleOption2<AccessibilityModifiersRequired> option, TCompilationUnitSyntax compilationUnitSyntax);
+
+    protected readonly DiagnosticDescriptor ModifierRemovedDescriptor = CreateDescriptorWithId(
+        IDEDiagnosticIds.AddAccessibilityModifiersDiagnosticId,
+        EnforceOnBuildValues.AddAccessibilityModifiers,
+        hasAnyCodeStyleOption: true,
+        new LocalizableResourceString(nameof(AnalyzersResources.Remove_accessibility_modifiers), AnalyzersResources.ResourceManager, typeof(AnalyzersResources)),
+        new LocalizableResourceString(nameof(AnalyzersResources.Accessibility_modifiers_unnecessary), AnalyzersResources.ResourceManager, typeof(AnalyzersResources)));
+
     protected static readonly ImmutableDictionary<string, string?> ModifiersAddedProperties = ImmutableDictionary<string, string?>.Empty.Add(
         AddAccessibilityModifiersConstants.ModifiersAdded, AddAccessibilityModifiersConstants.ModifiersAdded);
 
@@ -39,5 +52,25 @@ private void AnalyzeTree(SyntaxTreeAnalysisContext context, CompilationOptions c
         ProcessCompilationUnit(context, option, (TCompilationUnitSyntax)context.Tree.GetRoot(context.CancellationToken));
     }
 
-    protected abstract void ProcessCompilationUnit(SyntaxTreeAnalysisContext context, CodeStyleOption2<AccessibilityModifiersRequired> option, TCompilationUnitSyntax compilationUnitSyntax);
+    protected void CheckMemberAndReportDiagnostic(
+        SyntaxTreeAnalysisContext context,
+        CodeStyleOption2<AccessibilityModifiersRequired> option,
+        SyntaxNode member)
+    {
+        if (!this.AddAccessibilityModifiers.ShouldUpdateAccessibilityModifier(
+                this.AccessibilityFacts, member, option.Value, out var name, out var modifiersAdded))
+        {
+            return;
+        }
+
+        // Have an issue to flag, either add or remove. Report issue to user.
+        var additionalLocations = ImmutableArray.Create(member.GetLocation());
+        context.ReportDiagnostic(DiagnosticHelper.Create(
+            modifiersAdded ? Descriptor : ModifierRemovedDescriptor,
+            name.GetLocation(),
+            option.Notification,
+            context.Options,
+            additionalLocations: additionalLocations,
+            modifiersAdded ? ModifiersAddedProperties : null));
+    }
 }

src/Analyzers/Core/Analyzers/AnalyzersResources.resx

@@ -406,4 +406,7 @@
   <data name="Implement_through_0" xml:space="preserve">
     <value>Implement through '{0}'</value>
   </data>
+  <data name="Accessibility_modifiers_unnecessary" xml:space="preserve">
+    <value>Accessibility modifiers unnecessary</value>
+  </data>
 </root>