When Castle.Core is loaded in a collectible Assembly Load Context, use AssemblyBuilderAccess.RunAndCollect by default

ref/Castle.Core-net462.cs

@@ -2476,6 +2476,10 @@ public virtual void MethodsInspected() { }
         public virtual void NonProxyableMemberNotification(System.Type type, System.Reflection.MemberInfo memberInfo) { }
         public virtual bool ShouldInterceptMethod(System.Type type, System.Reflection.MethodInfo methodInfo) { }
     }
+    public static class AssemblyBuilderAccessDefaults
+    {
+        public static System.Reflection.Emit.AssemblyBuilderAccess Default { get; set; }
+    }
     public class CustomAttributeInfo : System.IEquatable<Castle.DynamicProxy.CustomAttributeInfo>
     {
         public CustomAttributeInfo(System.Reflection.ConstructorInfo constructor, object[] constructorArgs) { }

ref/Castle.Core-net6.0.cs

@@ -2444,6 +2444,10 @@ public virtual void MethodsInspected() { }
         public virtual void NonProxyableMemberNotification(System.Type type, System.Reflection.MemberInfo memberInfo) { }
         public virtual bool ShouldInterceptMethod(System.Type type, System.Reflection.MethodInfo methodInfo) { }
     }
+    public static class AssemblyBuilderAccessDefaults
+    {
+        public static System.Reflection.Emit.AssemblyBuilderAccess Default { get; set; }
+    }
     public class CustomAttributeInfo : System.IEquatable<Castle.DynamicProxy.CustomAttributeInfo>
     {
         public CustomAttributeInfo(System.Reflection.ConstructorInfo constructor, object[] constructorArgs) { }

ref/Castle.Core-netstandard2.0.cs

@@ -2442,6 +2442,10 @@ public virtual void MethodsInspected() { }
         public virtual void NonProxyableMemberNotification(System.Type type, System.Reflection.MemberInfo memberInfo) { }
         public virtual bool ShouldInterceptMethod(System.Type type, System.Reflection.MethodInfo methodInfo) { }
     }
+    public static class AssemblyBuilderAccessDefaults
+    {
+        public static System.Reflection.Emit.AssemblyBuilderAccess Default { get; set; }
+    }
     public class CustomAttributeInfo : System.IEquatable<Castle.DynamicProxy.CustomAttributeInfo>
     {
         public CustomAttributeInfo(System.Reflection.ConstructorInfo constructor, object[] constructorArgs) { }

ref/Castle.Core-netstandard2.1.cs

@@ -2442,6 +2442,10 @@ public virtual void MethodsInspected() { }
         public virtual void NonProxyableMemberNotification(System.Type type, System.Reflection.MemberInfo memberInfo) { }
         public virtual bool ShouldInterceptMethod(System.Type type, System.Reflection.MethodInfo methodInfo) { }
     }
+    public static class AssemblyBuilderAccessDefaults
+    {
+        public static System.Reflection.Emit.AssemblyBuilderAccess Default { get; set; }
+    }
     public class CustomAttributeInfo : System.IEquatable<Castle.DynamicProxy.CustomAttributeInfo>
     {
         public CustomAttributeInfo(System.Reflection.ConstructorInfo constructor, object[] constructorArgs) { }

src/Castle.Core/Components.DictionaryAdapter/DictionaryAdapterFactory.cs

@@ -27,6 +27,7 @@ namespace Castle.Components.DictionaryAdapter
 
 	using Castle.Components.DictionaryAdapter.Xml;
 	using Castle.Core.Internal;
+	using Castle.DynamicProxy;
 
 	/// <summary>
 	/// Uses Reflection.Emit to expose the properties of a dictionary
@@ -148,7 +149,7 @@ private object InternalGetAdapter(Type type, IDictionary dictionary, PropertyDes
 		private static TypeBuilder CreateTypeBuilder(Type type)
 		{
 			var assemblyName = new AssemblyName("CastleDictionaryAdapterAssembly");
-			var assemblyBuilder = AssemblyBuilder.DefineDynamicAssembly(assemblyName, AssemblyBuilderAccess.Run);
+			var assemblyBuilder = AssemblyBuilder.DefineDynamicAssembly(assemblyName, AssemblyBuilderAccessDefaults.Default);
 			var moduleBuilder = assemblyBuilder.DefineDynamicModule("CastleDictionaryAdapterModule");
 			return CreateAdapterType(type, moduleBuilder);
 		}

src/Castle.Core/DynamicProxy/AssemblyBuilderAccessDefaults.cs

@@ -0,0 +1,40 @@
+// Copyright 2004-2021 Castle Project - http://www.castleproject.org/
+// 
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// 
+//     http://www.apache.org/licenses/LICENSE-2.0
+// 
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+
+namespace Castle.DynamicProxy
+{
+	using System.Reflection.Emit;
+
+	public static class AssemblyBuilderAccessDefaults
+	{
+#if NET
+		// If Castle.Core is loaded in a collectible AssemblyLoadContext, the generated assembly should be collectible as well by default.
+		static readonly AssemblyBuilderAccess automatic = System.Runtime.Loader.AssemblyLoadContext.GetLoadContext(typeof(AssemblyBuilderAccessDefaults).Assembly).IsCollectible ? AssemblyBuilderAccess.RunAndCollect : AssemblyBuilderAccess.Run;
+#else
+		static readonly AssemblyBuilderAccess automatic = AssemblyBuilderAccess.Run;
+#endif
+		static AssemblyBuilderAccess? userSpecified;
+
+		/// <summary>
+		/// Get or set the default <see cref="System.Reflection.Emit.AssemblyBuilderAccess"/> to use when creating dynamic assemblies.
+		/// On .Net Core, the default is <see cref="System.Reflection.Emit.AssemblyBuilderAccess.RunAndCollect"/> if Castle.Core is loaded in a collectible AssemblyLoadContext.
+		/// </summary>
+		public static AssemblyBuilderAccess Default
+		{
+			get => userSpecified ?? automatic;
+			set => userSpecified = value;
+		}
+	}
+}

src/Castle.Core/DynamicProxy/ModuleScope.cs

@@ -335,9 +335,9 @@ private ModuleBuilder CreateModule(bool signStrongName)
 			{
 #if FEATURE_APPDOMAIN
 				var assemblyBuilder = AppDomain.CurrentDomain.DefineDynamicAssembly(
-					assemblyName, AssemblyBuilderAccess.Run);
+					assemblyName, AssemblyBuilderAccessDefaults.Default);
 #else
-				var assemblyBuilder = AssemblyBuilder.DefineDynamicAssembly(assemblyName, AssemblyBuilderAccess.Run);
+				var assemblyBuilder = AssemblyBuilder.DefineDynamicAssembly(assemblyName, AssemblyBuilderAccessDefaults.Default);
 #endif
 
 				var module = assemblyBuilder.DefineDynamicModule(moduleName);