Improve code style behavior.

src/Features/Core/Portable/UseAutoProperty/AbstractUseAutoPropertyAnalyzer.cs

@@ -45,15 +45,32 @@ protected sealed override void InitializeWorker(AnalysisContext context)
 
         private void AnalyzeSemanticModel(SemanticModelAnalysisContext context)
         {
+            var cancellationToken = context.CancellationToken;
+            var semanticModel = context.SemanticModel;
+
+            // Don't even bother doing the analysis if the user doesn't even want auto-props.
+            var optionSet = context.Options.GetDocumentOptionSetAsync(
+                semanticModel.SyntaxTree, cancellationToken).GetAwaiter().GetResult();
+            if (optionSet == null)
+            {
+                return;
+            }
+
+            var option = optionSet.GetOption(CodeStyleOptions.PreferAutoProperties, semanticModel.Language);
+            if (!option.Value)
+            {
+                return;
+            }
+
             var analysisResults = new List<AnalysisResult>();
             var ineligibleFields = new HashSet<IFieldSymbol>();
 
-            var root = context.SemanticModel.SyntaxTree.GetRoot(context.CancellationToken);
+            var root = semanticModel.SyntaxTree.GetRoot(cancellationToken);
             AnalyzeCompilationUnit(context, root, analysisResults);
 
             RegisterIneligibleFieldsAction(
                 analysisResults, ineligibleFields,
-                context.SemanticModel.Compilation, context.CancellationToken);
+                semanticModel.Compilation, cancellationToken);
             Process(analysisResults, ineligibleFields, context);
         }
 
@@ -275,32 +292,31 @@ private void Process(AnalysisResult result, SemanticModelAnalysisContext context
                 return;
             }
 
-            // Always offer the conversion if possible.  But only let the user know (by 
-            // fading/suggestions/squiggles) if their option is set to see this.
-
-            var option = optionSet.GetOption(CodeStyleOptions.PreferAutoProperties, propertyDeclaration.Language);
-            if (option.Value)
-            {
-                // Fade out the field/variable we are going to remove.
-                var diagnostic1 = Diagnostic.Create(UnnecessaryWithoutSuggestionDescriptor, nodeToFade.GetLocation());
-                context.ReportDiagnostic(diagnostic1);
-            }
-
             // Now add diagnostics to both the field and the property saying we can convert it to 
             // an auto property.  For each diagnostic store both location so we can easily retrieve
             // them when performing the code fix.
             var additionalLocations = ImmutableArray.Create(
                 propertyDeclaration.GetLocation(), variableDeclarator.GetLocation());
 
-            var diagnostic2 = Diagnostic.Create(HiddenDescriptor, propertyDeclaration.GetLocation(),
-                additionalLocations: additionalLocations);
-            context.ReportDiagnostic(diagnostic2);
+            var option = optionSet.GetOption(CodeStyleOptions.PreferAutoProperties, propertyDeclaration.Language);
+
+            var lowPriority = ImmutableDictionary<string, string>.Empty.Add("LowPriority", "");
 
             // Place the appropriate marker on the field depending on the user option.
-            var diagnostic3 = Diagnostic.Create(
+            var diagnostic1 = Diagnostic.Create(
                 GetFieldDescriptor(option), nodeToFade.GetLocation(),
-                additionalLocations: additionalLocations);
-            context.ReportDiagnostic(diagnostic3);
+                additionalLocations: additionalLocations,
+                properties: option.Notification.Value == DiagnosticSeverity.Hidden ? lowPriority : default);
+
+            // Also, place a hidden marker on the property.  If they bring up a lightbulb
+            // there, they'll be able to see that they can convert it to an auto-prop.
+            var diagnostic2 = Diagnostic.Create(
+                HiddenDescriptor, propertyDeclaration.GetLocation(),
+                additionalLocations: additionalLocations,
+                properties: lowPriority);
+
+            context.ReportDiagnostic(diagnostic1);
+            context.ReportDiagnostic(diagnostic2);
         }
 
         private DiagnosticDescriptor GetFieldDescriptor(CodeStyleOption<bool> styleOption)
@@ -315,7 +331,7 @@ private DiagnosticDescriptor GetFieldDescriptor(CodeStyleOption<bool> styleOptio
                 }
             }
 
-            return HiddenDescriptor;
+            return UnnecessaryWithSuggestionDescriptor;
         }
 
         protected virtual bool IsEligibleHeuristic(IFieldSymbol field, TPropertyDeclaration propertyDeclaration, Compilation compilation, CancellationToken cancellationToken)

src/Features/Core/Portable/UseAutoProperty/AbstractUseAutoPropertyCodeFixProvider.cs

@@ -46,10 +46,15 @@ public sealed override Task RegisterCodeFixesAsync(CodeFixContext context)
         {
             foreach (var diagnostic in context.Diagnostics)
             {
+                var priority = diagnostic.Properties.ContainsKey("LowPriority")
+                    ? CodeActionPriority.Low
+                    : CodeActionPriority.Medium;
+
                 context.RegisterCodeFix(
                     new UseAutoPropertyCodeAction(
                         FeaturesResources.Use_auto_property,
-                        c => ProcessResultAsync(context, diagnostic, c)),
+                        c => ProcessResultAsync(context, diagnostic, c),
+                        priority),
                     diagnostic);
             }
 
@@ -273,10 +278,13 @@ private static bool IsWrittenToOutsideOfConstructorOrProperty(
 
         private class UseAutoPropertyCodeAction : CodeAction.SolutionChangeAction
         {
-            public UseAutoPropertyCodeAction(string title, Func<CancellationToken, Task<Solution>> createChangedSolution)
+            public UseAutoPropertyCodeAction(string title, Func<CancellationToken, Task<Solution>> createChangedSolution, CodeActionPriority priority)
                 : base(title, createChangedSolution, title)
             {
+                this.Priority = priority;
             }
+
+            internal override CodeActionPriority Priority { get; }
         }
     }
 }