chore: remove dead code and simplify redundant state

- Remove unused AnyAncestorHasEquatable method and
  NearestComparerAncestorFullname property (set but never read)
- Make EqualityMemberModel.Ignored a derived property from EqualityType,
  removing redundant explicit assignments and double-check guard
- Simplify SetEqualityComparer by deriving custom-comparer detection
  via ReferenceEquals instead of tracking a separate boolean field
- Remove inconsistent internal modifier from TypeSymbolExtensions

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: diegofrata

Generator.Equals.Runtime/SetEqualityComparer.cs

@@ -11,21 +11,13 @@ public class SetEqualityComparer<T> : IEqualityComparer<IEnumerable<T>>
 
         public IEqualityComparer<T> EqualityComparer { get; }
 
-        readonly bool _hasCustomComparer;
-
-        public SetEqualityComparer() : this(DefaultEqualityComparer<T>.Default, hasCustomComparer: false)
+        public SetEqualityComparer() : this(DefaultEqualityComparer<T>.Default)
         {
         }
 
         public SetEqualityComparer(IEqualityComparer<T> equalityComparer)
-            : this(equalityComparer, hasCustomComparer: true)
-        {
-        }
-
-        SetEqualityComparer(IEqualityComparer<T> equalityComparer, bool hasCustomComparer)
         {
             EqualityComparer = equalityComparer;
-            _hasCustomComparer = hasCustomComparer;
         }
 
         public bool Equals(IEnumerable<T>? x, IEnumerable<T>? y)
@@ -38,7 +30,7 @@ public bool Equals(IEnumerable<T>? x, IEnumerable<T>? y)
 
             // When no custom comparer was specified, delegate to the set's own
             // comparer so we respect whatever the collection was built with.
-            if (!_hasCustomComparer)
+            if (ReferenceEquals(EqualityComparer, DefaultEqualityComparer<T>.Default))
             {
                 if (x is ISet<T> xSet)
                     return xSet.SetEquals(y);

Generator.Equals/EqualityGeneratorBase.cs

@@ -315,7 +315,7 @@ static string GetComparerEquals(EqualityMemberModel memberModel, string left, st
 
         static void BuildMemberInequality(EqualityMemberModel memberModel, IndentedTextWriter writer, string left, string right, string pathExpr)
         {
-            if (memberModel.Ignored || memberModel.EqualityType == EqualityType.IgnoreEquality)
+            if (memberModel.Ignored)
             {
                 return;
             }

Generator.Equals/EqualityMemberModelTransformer.cs

@@ -109,7 +109,6 @@ public static EqualityMemberModel BuildEqualityModel(
                 MemberName = propertyName, IsField = isField,
                 TypeName = typeName,
                 EqualityType = EqualityType.IgnoreEquality,
-                Ignored = true,
             };
         }
 
@@ -273,7 +272,6 @@ public static EqualityMemberModel BuildEqualityModel(
             MemberName = propertyName, IsField = isField,
             TypeName = typeName,
             EqualityType = isIgnored ? EqualityType.IgnoreEquality : EqualityType.DefaultEquality,
-            Ignored = isIgnored
         };
     }
 }

Generator.Equals/EqualityTypeModelTransformer.cs

@@ -84,9 +84,7 @@ public EqualityTypeModelTransformer(GeneratorAttributeSyntaxContext context)
         // reach a meaningful equality implementation. We walk up the inheritance chain
         // to find if any ancestor has a generated EqualityComparer. If so, we should call
         // that ancestor's comparer.
-        var nearestComparerAncestor = FindNearestComparerAncestor(symbol.BaseType, attributesMetadata);
-        var baseHasEquatable = nearestComparerAncestor != null;
-        var nearestComparerAncestorFullname = nearestComparerAncestor?.ToDisplayString(SymbolDisplayFormat.FullyQualifiedFormat);
+        var baseHasEquatable = FindNearestComparerAncestor(symbol.BaseType, attributesMetadata) != null;
 
         var bems = EqualityMemberModelTransformer.BuildEqualityModels(symbol, attributesMetadata, explicitMode, filter);
 
@@ -107,7 +105,6 @@ public EqualityTypeModelTransformer(GeneratorAttributeSyntaxContext context)
             IsSealed = symbol.IsSealed,
             BaseTypeName = baseTypeName,
             BaseTypeFullname = baseTypeFullname,
-            NearestComparerAncestorFullname = nearestComparerAncestorFullname,
             Fullname = fullname,
             SyntaxKind = _context.TargetNode.Kind(),
             BaseHasEquatable = baseHasEquatable,
@@ -180,10 +177,6 @@ static bool HasGeneratedEqualityComparer(INamedTypeSymbol type)
     /// This includes types with [Equatable] attribute or types with a generated EqualityComparer (for cross-assembly).
     /// If so, calling the base comparer will reach that implementation.
     /// </summary>
-    static bool AnyAncestorHasEquatable(INamedTypeSymbol? baseType, AttributesMetadata attributesMetadata)
-    {
-        return FindNearestComparerAncestor(baseType, attributesMetadata) != null;
-    }
 
     /// <summary>
     /// Collects all properties from ancestor types that don't have [Equatable] or a generated EqualityComparer.

Generator.Equals/Extensions/TypeSymbolExtensions.cs

@@ -8,7 +8,7 @@ namespace Generator.Equals.Extensions;
 /// <summary>
 /// Extension methods for <see cref="ITypeSymbol"/> used by the analyzer.
 /// </summary>
-internal static class TypeSymbolExtensions
+static class TypeSymbolExtensions
 {
     private static readonly HashSet<string> PrimitiveTypeNames = new()
     {

Generator.Equals/Models/EqualityMemberModel.cs

@@ -14,7 +14,7 @@ sealed record EqualityMemberModel
     public double? Precision { get; init; }
     public bool IsNullable { get; init; }
 
-    public bool Ignored { get; init; }
+    public bool Ignored => EqualityType == EqualityType.IgnoreEquality;
     public bool ComparerHasStaticInstance { get; init; }
 
     // Element comparer properties for collection equality attributes

Generator.Equals/Models/EqualityTypeModel.cs

@@ -15,12 +15,6 @@ sealed record EqualityTypeModel
     /// </summary>
     public string? BaseTypeFullname { get; init; }
 
-    /// <summary>
-    /// Fully qualified name of the nearest ancestor that has a generated EqualityComparer.
-    /// This is used when the immediate base doesn't have a comparer but an ancestor does.
-    /// </summary>
-    public string? NearestComparerAncestorFullname { get; init; }
-
     public required bool IsSealed { get; init; }
     public required EquatableImmutableArray<ContainingSymbol> ContainingSymbols { get; init; }
     public required AttributesMetadata AttributesMetadata { get; init; }