Fix handling of implicitly declared EqualityContract on record types in validation generator (#62511)

Co-authored-by: captainsafia <1857993+captainsafia@users.noreply.github.com>
Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>

Author: Copilot

src/Shared/RoslynUtils/WellKnownTypeData.cs

@@ -123,6 +123,7 @@ public enum WellKnownType
         System_ComponentModel_DataAnnotations_ValidationAttribute,
         System_ComponentModel_DataAnnotations_RequiredAttribute,
         System_ComponentModel_DataAnnotations_CustomValidationAttribute,
+        System_Type,
     }
 
     public static string[] WellKnownTypeNames =
@@ -243,5 +244,6 @@ public enum WellKnownType
         "System.ComponentModel.DataAnnotations.ValidationAttribute",
         "System.ComponentModel.DataAnnotations.RequiredAttribute",
         "System.ComponentModel.DataAnnotations.CustomValidationAttribute",
+        "System.Type",
     ];
 }

src/Validation/gen/Extensions/ISymbolExtensions.cs

@@ -3,6 +3,7 @@
 
 using System;
 using System.Linq;
+using Microsoft.AspNetCore.App.Analyzers.Infrastructure;
 using Microsoft.CodeAnalysis;
 
 namespace Microsoft.Extensions.Validation;
@@ -32,4 +33,9 @@ attribute.AttributeClass is { } attributeClass &&
 
         return property.Name;
     }
+
+    public static bool IsEqualityContract(this IPropertySymbol prop, WellKnownTypes wellKnownTypes) =>
+        prop.Name == "EqualityContract"
+        && SymbolEqualityComparer.Default.Equals(prop.Type, wellKnownTypes.Get(WellKnownTypeData.WellKnownType.System_Type))
+        && prop.DeclaredAccessibility == Accessibility.Protected;
 }

src/Validation/gen/Parsers/ValidationsGenerator.TypesParser.cs

@@ -162,7 +162,9 @@ internal ImmutableArray<ValidatableProperty> ExtractValidatableMembers(ITypeSymb
         {
             // Skip compiler generated properties and properties already processed via
             // the record processing logic above.
-            if (member.IsImplicitlyDeclared || resolvedRecordProperty.Contains(member, SymbolEqualityComparer.Default))
+            if (member.IsImplicitlyDeclared 
+                || member.IsEqualityContract(wellKnownTypes) 
+                || resolvedRecordProperty.Contains(member, SymbolEqualityComparer.Default))
             {
                 continue;
             }