Use 'field'

Author: CyrusNajmabadi

src/Workspaces/Core/Portable/Recommendations/AbstractRecommendationService.cs

@@ -2,6 +2,7 @@
 // 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;
 using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Linq;
@@ -108,7 +109,7 @@ internal bool ShouldIncludeSymbol(ISymbol symbol)
                 return symbol.IsOrContainsAccessibleAttribute(
                     _context.SemanticModel.GetEnclosingNamedType(_context.LeftToken.SpanStart, _cancellationToken)!,
                     _context.SemanticModel.Compilation.Assembly,
-                    _context.ValidAttributeTargets,
+                    _context.ValidAttributeTargets ?? AttributeTargets.All,
                     _cancellationToken);
             }
 

src/Workspaces/SharedUtilitiesAndExtensions/Workspace/CSharp/Extensions/ContextQuery/CSharpSyntaxContext.cs

@@ -47,8 +47,6 @@ internal sealed class CSharpSyntaxContext : SyntaxContext
 
     public readonly ISet<SyntaxKind> PrecedingModifiers;
 
-    private AttributeTargets? _lazyValidAttributeTargets;
-
     private CSharpSyntaxContext(
         Document document,
         SemanticModel semanticModel,
@@ -516,7 +514,7 @@ private static bool ComputeIsAwaitKeywordContext(
         return false;
     }
 
-    public override AttributeTargets ValidAttributeTargets => _lazyValidAttributeTargets ??= ComputeValidAttributeTargets();
+    public override AttributeTargets? ValidAttributeTargets => field ??= ComputeValidAttributeTargets();
 
     private AttributeTargets ComputeValidAttributeTargets()
     {

src/Workspaces/SharedUtilitiesAndExtensions/Workspace/Core/Extensions/ContextQuery/SyntaxContext.cs

@@ -98,11 +98,10 @@ internal abstract class SyntaxContext(
     public ImmutableArray<ITypeSymbol> InferredTypes { get; } = document.GetRequiredLanguageService<ITypeInferenceService>().InferTypes(semanticModel, position, cancellationToken);
 
     /// <summary>
-    /// Gets the valid attribute targets for the current attribute context.
-    /// Returns <see cref="AttributeTargets.All"/> if not in an attribute context or if language-specific
-    /// filtering is not implemented.
+    /// Gets the valid attribute targets for the current attribute context. Returns <see langword="null"/> if not in an
+    /// attribute context or if language-specific filtering is not implemented.
     /// </summary>
-    public virtual AttributeTargets ValidAttributeTargets => AttributeTargets.All;
+    public virtual AttributeTargets? ValidAttributeTargets => null;
 
     public TService? GetLanguageService<TService>() where TService : class, ILanguageService
         => Document.GetLanguageService<TService>();