Add AbstractUnresolvedEntity.Clone() method.

ICSharpCode.NRefactory/TypeSystem/CecilLoader.cs

@@ -1846,6 +1846,11 @@ namespace ICSharpCode.NRefactory.TypeSystem
 				// FlagHasNoExtensionMethods is unused in LazyCecilTypeDefinition
 			}
 			
+			public override object Clone()
+			{
+				throw new NotSupportedException();
+			}
+			
 			public IType Resolve(ITypeResolveContext context)
 			{
 				if (context == null)

ICSharpCode.NRefactory/TypeSystem/Implementation/AbstractUnresolvedEntity.cs

@@ -96,6 +96,23 @@ namespace ICSharpCode.NRefactory.TypeSystem.Implementation
 				rareFields.ApplyInterningProvider(provider);
 		}
 		
+		/// <summary>
+		/// Creates a shallow clone of this entity.
+		/// Collections (e.g. a type's member list) will be cloned as well, but the elements
+		/// of said list will not be.
+		/// If this instance is frozen, the clone will be unfrozen.
+		/// </summary>
+		public virtual object Clone()
+		{
+			var copy = (AbstractUnresolvedEntity)MemberwiseClone();
+			copy.flags[FlagFrozen] = false;
+			if (attributes != null)
+				copy.attributes = new List<IUnresolvedAttribute>(attributes);
+			if (rareFields != null)
+				copy.rareFields = (RareFields)rareFields.Clone();
+			return copy;
+		}
+		
 		[Serializable]
 		internal class RareFields
 		{
@@ -110,6 +127,11 @@ namespace ICSharpCode.NRefactory.TypeSystem.Implementation
 			public virtual void ApplyInterningProvider(IInterningProvider provider)
 			{
 			}
+			
+			public virtual object Clone()
+			{
+				return MemberwiseClone();
+			}
 		}
 		
 		protected void ThrowIfFrozen()

ICSharpCode.NRefactory/TypeSystem/Implementation/AbstractUnresolvedMember.cs

@@ -39,6 +39,20 @@ namespace ICSharpCode.NRefactory.TypeSystem.Implementation
 			interfaceImplementations = provider.InternList(interfaceImplementations);
 		}
 		
+		protected override void FreezeInternal()
+		{
+			base.FreezeInternal();
+			interfaceImplementations = FreezableHelper.FreezeList(interfaceImplementations);
+		}
+		
+		public override object Clone()
+		{
+			var copy = (AbstractUnresolvedMember)base.Clone();
+			if (interfaceImplementations != null)
+				copy.interfaceImplementations = new List<IMemberReference>(interfaceImplementations);
+			return copy;
+		}
+		
 		/*
 		[Serializable]
 		internal new class RareFields : AbstractUnresolvedEntity.RareFields
@@ -56,6 +70,8 @@ namespace ICSharpCode.NRefactory.TypeSystem.Implementation
 				interfaceImplementations = FreezableHelper.FreezeListAndElements(interfaceImplementations);
 				base.FreezeInternal();
 			}
+			
+			override Clone(){}
 		}
 		
 		internal override AbstractUnresolvedEntity.RareFields WriteRareFields()
@@ -83,20 +99,16 @@ namespace ICSharpCode.NRefactory.TypeSystem.Implementation
 			}
 		}
 		
-		/*
 		public IList<IMemberReference> ExplicitInterfaceImplementations {
 			get {
+				/*
 				RareFields rareFields = (RareFields)this.rareFields;
 				if (rareFields == null || rareFields.interfaceImplementations == null) {
 					rareFields = (RareFields)WriteRareFields();
 					return rareFields.interfaceImplementations = new List<IMemberReference>();
 				}
 				return rareFields.interfaceImplementations;
-			}
-		}*/
-		
-		public IList<IMemberReference> ExplicitInterfaceImplementations {
-			get {
+				*/
 				if (interfaceImplementations == null)
 					interfaceImplementations = new List<IMemberReference>();
 				return interfaceImplementations;

ICSharpCode.NRefactory/TypeSystem/Implementation/DefaultUnresolvedMethod.cs

@@ -42,6 +42,18 @@ namespace ICSharpCode.NRefactory.TypeSystem.Implementation
 			base.FreezeInternal();
 		}
 		
+		public override object Clone()
+		{
+			var copy = (DefaultUnresolvedMethod)base.Clone();
+			if (returnTypeAttributes != null)
+				copy.returnTypeAttributes = new List<IUnresolvedAttribute>(returnTypeAttributes);
+			if (typeParameters != null)
+				copy.typeParameters = new List<IUnresolvedTypeParameter>(typeParameters);
+			if (parameters != null)
+				copy.parameters = new List<IUnresolvedParameter>(parameters);
+			return copy;
+		}
+		
 		public override void ApplyInterningProvider(IInterningProvider provider)
 		{
 			base.ApplyInterningProvider(provider);

ICSharpCode.NRefactory/TypeSystem/Implementation/DefaultUnresolvedProperty.cs

@@ -39,6 +39,14 @@ namespace ICSharpCode.NRefactory.TypeSystem.Implementation
 			base.FreezeInternal();
 		}
 		
+		public override object Clone()
+		{
+			var copy = (DefaultUnresolvedProperty)base.Clone();
+			if (parameters != null)
+				copy.parameters = new List<IUnresolvedParameter>(parameters);
+			return copy;
+		}
+		
 		public override void ApplyInterningProvider(IInterningProvider provider)
 		{
 			base.ApplyInterningProvider(provider);

ICSharpCode.NRefactory/TypeSystem/Implementation/DefaultUnresolvedTypeDefinition.cs

@@ -75,6 +75,29 @@ namespace ICSharpCode.NRefactory.TypeSystem.Implementation
 			this.UnresolvedFile = declaringTypeDefinition.UnresolvedFile;
 		}
 		
+		protected override void FreezeInternal()
+		{
+			base.FreezeInternal();
+			baseTypes = FreezableHelper.FreezeList(baseTypes);
+			typeParameters = FreezableHelper.FreezeListAndElements(typeParameters);
+			nestedTypes = FreezableHelper.FreezeListAndElements(nestedTypes);
+			members = FreezableHelper.FreezeListAndElements(members);
+		}
+		
+		public override object Clone()
+		{
+			var copy = (DefaultUnresolvedTypeDefinition)base.Clone();
+			if (baseTypes != null)
+				copy.baseTypes = new List<ITypeReference>(baseTypes);
+			if (typeParameters != null)
+				copy.typeParameters = new List<IUnresolvedTypeParameter>(typeParameters);
+			if (nestedTypes != null)
+				copy.nestedTypes = new List<IUnresolvedTypeDefinition>(nestedTypes);
+			if (members != null)
+				copy.members = new List<IUnresolvedMember>(members);
+			return copy;
+		}
+		
 		public TypeKind Kind {
 			get { return kind; }
 			set {