Do not check object references for equality after hot reload

src/coreclr/System.Private.CoreLib/src/System/Reflection/Metadata/RuntimeTypeMetadataUpdateHandler.cs

@@ -11,11 +11,16 @@ namespace System.Reflection.Metadata
     /// <summary>Metadata update handler used to clear a Type's reflection cache in response to a metadata update notification.</summary>
     internal static class RuntimeTypeMetadataUpdateHandler
     {
+        private static bool s_cacheCleared;
+        public static bool MetadataUpdaterSupportedAndCacheCleared => MetadataUpdater.IsSupported && s_cacheCleared;
+
         /// <summary>Clear type caches in response to an update notification.</summary>
         /// <param name="types">The specific types to be cleared, or null to clear everything.</param>
         [UnconditionalSuppressMessage("ReflectionAnalysis", "IL2026:RequiresUnreferencedCode", Justification = "Clearing the caches on a Type isn't affected if a Type is trimmed, or has any of its members trimmed.")]
         public static void ClearCache(Type[]? types)
         {
+            s_cacheCleared = true;
+
             if (RequiresClearingAllTypes(types))
             {
                 // TODO: This should ideally be in a QCall in the runtime.  As written here:

src/coreclr/System.Private.CoreLib/src/System/Reflection/RuntimeConstructorInfo.CoreCLR.cs

@@ -5,6 +5,7 @@
 using System.Diagnostics;
 using System.Diagnostics.CodeAnalysis;
 using System.Globalization;
+using System.Reflection.Metadata;
 using System.Runtime.CompilerServices;
 using System.Text;
 using System.Threading;
@@ -118,6 +119,15 @@ public override string ToString()
 
             return m_toString;
         }
+
+        public override bool Equals(object? obj) =>
+            obj == (object)this ||
+                (RuntimeTypeMetadataUpdateHandler.MetadataUpdaterSupportedAndCacheCleared &&
+                    obj is RuntimeConstructorInfo m &&
+                    MetadataToken == m.MetadataToken &&
+                    RuntimeTypeHandle.GetModule(m_declaringType).Equals(RuntimeTypeHandle.GetModule(m.m_declaringType)));
+
+        public override int GetHashCode() => m_handle.GetHashCode();
         #endregion
 
         #region ICustomAttributeProvider

src/coreclr/System.Private.CoreLib/src/System/Reflection/RuntimeEventInfo.cs

@@ -3,6 +3,7 @@
 
 using System.Collections.Generic;
 using System.Diagnostics;
+using System.Reflection.Metadata;
 using RuntimeTypeCache = System.RuntimeType.RuntimeTypeCache;
 
 namespace System.Reflection
@@ -68,6 +69,12 @@ public override string ToString()
 
             return m_addMethod.GetParametersNoCopy()[0].ParameterType.FormatTypeName() + " " + Name;
         }
+
+        public override bool Equals(object? obj) =>
+            obj == (object)this ||
+            (RuntimeTypeMetadataUpdateHandler.MetadataUpdaterSupportedAndCacheCleared && CacheEquals(obj));
+
+        public override int GetHashCode() => HashCode.Combine(m_token.GetHashCode(), RuntimeTypeHandle.GetModule(m_declaringType).GetHashCode());
         #endregion
 
         #region ICustomAttributeProvider

src/coreclr/System.Private.CoreLib/src/System/Reflection/RuntimeFieldInfo.cs

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System.Collections.Generic;
+using System.Reflection.Metadata;
 using RuntimeTypeCache = System.RuntimeType.RuntimeTypeCache;
 
 namespace System.Reflection
@@ -46,6 +47,12 @@ internal RuntimeType GetDeclaringTypeInternal()
 
         public override Module Module => GetRuntimeModule();
         public override bool IsCollectible => m_declaringType.IsCollectible;
+
+        public override bool Equals(object? obj) =>
+            obj == (object)this ||
+            (RuntimeTypeMetadataUpdateHandler.MetadataUpdaterSupportedAndCacheCleared && CacheEquals(obj));
+
+        public override int GetHashCode() => HashCode.Combine(MetadataToken.GetHashCode(), Module.GetHashCode());
         #endregion
 
         #region Object Overrides

src/coreclr/System.Private.CoreLib/src/System/Reflection/RuntimeMethodInfo.CoreCLR.cs

@@ -5,6 +5,7 @@
 using System.Diagnostics;
 using System.Diagnostics.CodeAnalysis;
 using System.Globalization;
+using System.Reflection.Metadata;
 using System.Runtime.CompilerServices;
 using System.Security;
 using System.Text;
@@ -163,49 +164,56 @@ public override int GetHashCode()
             if (IsGenericMethod)
                 return ValueType.GetHashCodeOfPtr(m_handle);
             else
-                return base.GetHashCode();
+                return m_handle.GetHashCode();
         }
 
         public override bool Equals(object? obj)
         {
-            if (!IsGenericMethod)
-                return obj == (object)this;
+            if (IsGenericMethod)
+            {
+                // We cannot do simple object identity comparisons for generic methods.
+                // Equals will be called in CerHashTable when RuntimeType+RuntimeTypeCache.GetGenericMethodInfo()
+                // retrieve items from and insert items into s_methodInstantiations which is a CerHashtable.
 
-            // We cannot do simple object identity comparisons for generic methods.
-            // Equals will be called in CerHashTable when RuntimeType+RuntimeTypeCache.GetGenericMethodInfo()
-            // retrieve items from and insert items into s_methodInstantiations which is a CerHashtable.
+                RuntimeMethodInfo? mi = obj as RuntimeMethodInfo;
 
-            RuntimeMethodInfo? mi = obj as RuntimeMethodInfo;
+                if (mi == null || !mi.IsGenericMethod)
+                    return false;
 
-            if (mi == null || !mi.IsGenericMethod)
-                return false;
+                // now we know that both operands are generic methods
 
-            // now we know that both operands are generic methods
+                IRuntimeMethodInfo handle1 = RuntimeMethodHandle.StripMethodInstantiation(this);
+                IRuntimeMethodInfo handle2 = RuntimeMethodHandle.StripMethodInstantiation(mi);
+                if (handle1.Value.Value != handle2.Value.Value)
+                    return false;
 
-            IRuntimeMethodInfo handle1 = RuntimeMethodHandle.StripMethodInstantiation(this);
-            IRuntimeMethodInfo handle2 = RuntimeMethodHandle.StripMethodInstantiation(mi);
-            if (handle1.Value.Value != handle2.Value.Value)
-                return false;
+                Type[] lhs = GetGenericArguments();
+                Type[] rhs = mi.GetGenericArguments();
 
-            Type[] lhs = GetGenericArguments();
-            Type[] rhs = mi.GetGenericArguments();
+                if (lhs.Length != rhs.Length)
+                    return false;
 
-            if (lhs.Length != rhs.Length)
-                return false;
+                for (int i = 0; i < lhs.Length; i++)
+                {
+                    if (lhs[i] != rhs[i])
+                        return false;
+                }
 
-            for (int i = 0; i < lhs.Length; i++)
-            {
-                if (lhs[i] != rhs[i])
+                if (DeclaringType != mi.DeclaringType)
                     return false;
-            }
 
-            if (DeclaringType != mi.DeclaringType)
-                return false;
+                if (ReflectedType != mi.ReflectedType)
+                    return false;
 
-            if (ReflectedType != mi.ReflectedType)
-                return false;
+                return true;
+            }
+
+            return obj == (object)this ||
+                (RuntimeTypeMetadataUpdateHandler.MetadataUpdaterSupportedAndCacheCleared &&
+                    obj is RuntimeMethodInfo m &&
+                    m.MetadataToken == MetadataToken &&
+                    RuntimeTypeHandle.GetModule(m_declaringType).Equals(RuntimeTypeHandle.GetModule(m.m_declaringType)));
 
-            return true;
         }
         #endregion
 

src/coreclr/System.Private.CoreLib/src/System/Reflection/RuntimeParameterInfo.cs

@@ -3,6 +3,7 @@
 
 using System.Collections.Generic;
 using System.Diagnostics;
+using System.Reflection.Metadata;
 using System.Runtime.CompilerServices;
 using MdToken = System.Reflection.MetadataToken;
 
@@ -496,6 +497,14 @@ public override Type[] GetOptionalCustomModifiers()
                 m_signature.GetCustomModifiers(PositionImpl + 1, false);
         }
 
+        public override bool Equals(object? obj) =>
+            obj == (object)this ||
+                (RuntimeTypeMetadataUpdateHandler.MetadataUpdaterSupportedAndCacheCleared &&
+                    obj is RuntimeParameterInfo m &&
+                    m_tkParamDef == m.m_tkParamDef &&
+                    GetRuntimeModule()!.Equals(m.GetRuntimeModule()));
+
+        public override int GetHashCode() => HashCode.Combine(m_tkParamDef.GetHashCode(), GetRuntimeModule()!.GetHashCode());
         #endregion
 
         #region ICustomAttributeProvider

src/coreclr/System.Private.CoreLib/src/System/Reflection/RuntimePropertyInfo.cs

@@ -4,6 +4,7 @@
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Globalization;
+using System.Reflection.Metadata;
 using System.Text;
 using RuntimeTypeCache = System.RuntimeType.RuntimeTypeCache;
 
@@ -179,6 +180,12 @@ public override IList<CustomAttributeData> GetCustomAttributesData()
         public override Module Module => GetRuntimeModule();
         internal RuntimeModule GetRuntimeModule() { return m_declaringType.GetRuntimeModule(); }
         public override bool IsCollectible => m_declaringType.IsCollectible;
+
+        public override bool Equals(object? obj) =>
+            obj == (object)this ||
+                (RuntimeTypeMetadataUpdateHandler.MetadataUpdaterSupportedAndCacheCleared && CacheEquals(obj));
+
+        public override int GetHashCode() => HashCode.Combine(m_token.GetHashCode(), Module.GetHashCode());
         #endregion
 
         #region PropertyInfo Overrides