Simplify code.

src/Features/Core/Portable/Diagnostics/Analyzers/NamingStyleDiagnosticAnalyzerBase.cs

@@ -44,22 +44,16 @@ private void CompilationStartAction(CompilationStartAnalysisContext context)
         {
             var idToCachedResult = new ConcurrentDictionary<Guid, ConcurrentDictionary<string, string>>(
                 concurrencyLevel: 2, capacity: 0);
-            var preferencesToRules = new ConcurrentDictionary<NamingStylePreferences, NamingStyleRules>(
-                concurrencyLevel: 2, capacity: 0, comparer: ReferenceEqualityComparer.Instance);
 
-            context.RegisterSymbolAction(c => SymbolAction(c, idToCachedResult, preferencesToRules), _symbolKinds);
+            context.RegisterSymbolAction(c => SymbolAction(c, idToCachedResult), _symbolKinds);
         }
 
         private static readonly Func<Guid, ConcurrentDictionary<string, string>> s_createCache =
             _ => new ConcurrentDictionary<string, string>(concurrencyLevel: 2, capacity: 0);
 
-        private static readonly Func<NamingStylePreferences, NamingStyleRules> s_createRules =
-            p => p.GetNamingStyleRules();
-
         private void SymbolAction(
             SymbolAnalysisContext context,
-            ConcurrentDictionary<Guid, ConcurrentDictionary<string, string>> idToCachedResult,
-            ConcurrentDictionary<NamingStylePreferences, NamingStyleRules> preferencesToRules)
+            ConcurrentDictionary<Guid, ConcurrentDictionary<string, string>> idToCachedResult)
         { 
             var namingPreferences = context.GetNamingStylePreferencesAsync().GetAwaiter().GetResult();
             if (namingPreferences == null)
@@ -67,7 +61,7 @@ private void CompilationStartAction(CompilationStartAnalysisContext context)
                 return;
             }
 
-            var namingStyleRules = preferencesToRules.GetOrAdd(namingPreferences, s_createRules);
+            var namingStyleRules = namingPreferences.Rules;
 
             if (!namingStyleRules.TryGetApplicableRule(context.Symbol, out var applicableRule) ||
                 applicableRule.EnforcementLevel == DiagnosticSeverity.Hidden)

src/Workspaces/Core/Portable/NamingStyles/Serialization/NamingStylePreferences.cs

@@ -23,6 +23,8 @@ internal class NamingStylePreferences : IEquatable<NamingStylePreferences>
         public readonly ImmutableArray<MutableNamingStyle> NamingStyles;
         public readonly ImmutableArray<SerializableNamingRule> NamingRules;
 
+        private readonly Lazy<NamingStyleRules> _lazyRules;
+
         internal NamingStylePreferences(
             ImmutableArray<SymbolSpecification> symbolSpecifications,
             ImmutableArray<MutableNamingStyle> namingStyles,
@@ -31,6 +33,8 @@ internal class NamingStylePreferences : IEquatable<NamingStylePreferences>
             SymbolSpecifications = symbolSpecifications;
             NamingStyles = namingStyles;
             NamingRules = namingRules;
+
+            _lazyRules = new Lazy<NamingStyleRules>(CreateRules, isThreadSafe: true);
         }
 
         internal NamingStylePreferences()
@@ -45,19 +49,15 @@ internal NamingStylePreferences()
         public static string DefaultNamingPreferencesString => _defaultNamingPreferencesString;
 
         internal MutableNamingStyle GetNamingStyle(Guid namingStyleID)
-        {
-            return NamingStyles.Single(s => s.ID == namingStyleID);
-        }
+            => NamingStyles.Single(s => s.ID == namingStyleID);
 
         internal SymbolSpecification GetSymbolSpecification(Guid symbolSpecificationID)
-        {
-            return SymbolSpecifications.Single(s => s.ID == symbolSpecificationID);
-        }
+            => SymbolSpecifications.Single(s => s.ID == symbolSpecificationID);
 
-        public NamingStyleRules GetNamingStyleRules()
-        {
-            return new NamingStyleRules(NamingRules.Select(r => r.GetRule(this)).ToImmutableArray());
-        }
+        public NamingStyleRules Rules => _lazyRules.Value;
+
+        public NamingStyleRules CreateRules()
+            => new NamingStyleRules(NamingRules.Select(r => r.GetRule(this)).ToImmutableArray());
 
         internal XElement CreateXElement()
         {
@@ -156,15 +156,15 @@ public bool Equals(NamingStylePreferences other)
             {
                 return true;
             }
-            else if(leftIsNull)
+            else if (leftIsNull)
             {
                 return false;
             }
-            else if(rightIsNull)
+            else if (rightIsNull)
             {
                 return false;
             }
-            
+
             return left.Equals(right);
         }