Delete Null Objects

ICSharpCode.Decompiler/CSharp/Syntax/AstNode.cs

@@ -43,45 +43,6 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 		// the Root role must be available when creating the null nodes, so we can't put it in the Roles class
 		internal static readonly Role<AstNode?> RootRole = new Role<AstNode?>("Root", null);
 
-		#region Null
-		public static readonly AstNode Null = new NullAstNode();
-
-		sealed class NullAstNode : AstNode
-		{
-			public override NodeType NodeType {
-				get {
-					return NodeType.Unknown;
-				}
-			}
-
-			public override bool IsNull {
-				get {
-					return true;
-				}
-			}
-
-			public override void AcceptVisitor(IAstVisitor visitor)
-			{
-				visitor.VisitNullNode(this);
-			}
-
-			public override T AcceptVisitor<T>(IAstVisitor<T> visitor)
-			{
-				return visitor.VisitNullNode(this);
-			}
-
-			public override S AcceptVisitor<T, S>(IAstVisitor<T, S> visitor, T data)
-			{
-				return visitor.VisitNullNode(this, data);
-			}
-
-			protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
-			{
-				return other == null || other.IsNull;
-			}
-		}
-		#endregion
-
 		#region PatternPlaceholder
 		public static implicit operator AstNode?(PatternMatching.Pattern? pattern)
 		{

ICSharpCode.Decompiler/CSharp/Syntax/AstType.cs

@@ -31,44 +31,6 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 	[DecompilerAstNode(true)]
 	public abstract partial class AstType : AstNode
 	{
-		#region Null
-		public new static readonly AstType Null = new NullAstType();
-
-		sealed class NullAstType : AstType
-		{
-			public override bool IsNull {
-				get {
-					return true;
-				}
-			}
-
-			public override void AcceptVisitor(IAstVisitor visitor)
-			{
-				visitor.VisitNullNode(this);
-			}
-
-			public override T AcceptVisitor<T>(IAstVisitor<T> visitor)
-			{
-				return visitor.VisitNullNode(this);
-			}
-
-			public override S AcceptVisitor<T, S>(IAstVisitor<T, S> visitor, T data)
-			{
-				return visitor.VisitNullNode(this, data);
-			}
-
-			protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
-			{
-				return other == null || other.IsNull;
-			}
-
-			public override ITypeReference ToTypeReference(NameLookupMode lookupMode, InterningProvider interningProvider)
-			{
-				return SpecialType.UnknownType;
-			}
-		}
-		#endregion
-
 		#region PatternPlaceholder
 		public static implicit operator AstType(PatternMatching.Pattern pattern)
 		{

ICSharpCode.Decompiler/CSharp/Syntax/CSharpTokenNode.cs

@@ -37,40 +37,6 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 	[DecompilerAstNode(true)]
 	public partial class CSharpTokenNode : AstNode
 	{
-		public static new readonly CSharpTokenNode Null = new NullCSharpTokenNode();
-		class NullCSharpTokenNode : CSharpTokenNode
-		{
-			public override bool IsNull {
-				get {
-					return true;
-				}
-			}
-
-			public NullCSharpTokenNode() : base(TextLocation.Empty, null)
-			{
-			}
-
-			public override void AcceptVisitor(IAstVisitor visitor)
-			{
-				visitor.VisitNullNode(this);
-			}
-
-			public override T AcceptVisitor<T>(IAstVisitor<T> visitor)
-			{
-				return visitor.VisitNullNode(this);
-			}
-
-			public override S AcceptVisitor<T, S>(IAstVisitor<T, S> visitor, T data)
-			{
-				return visitor.VisitNullNode(this, data);
-			}
-
-			protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
-			{
-				return other == null || other.IsNull;
-			}
-		}
-
 		public override NodeType NodeType {
 			get {
 				return NodeType.Token;

ICSharpCode.Decompiler/CSharp/Syntax/Expressions/ArrayInitializerExpression.cs

@@ -60,39 +60,6 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			this.Elements.AddRange(elements);
 		}
 
-		#region Null
-		public new static readonly ArrayInitializerExpression Null = new NullArrayInitializerExpression();
-
-		sealed class NullArrayInitializerExpression : ArrayInitializerExpression
-		{
-			public override bool IsNull {
-				get {
-					return true;
-				}
-			}
-
-			public override void AcceptVisitor(IAstVisitor visitor)
-			{
-				visitor.VisitNullNode(this);
-			}
-
-			public override T AcceptVisitor<T>(IAstVisitor<T> visitor)
-			{
-				return visitor.VisitNullNode(this);
-			}
-
-			public override S AcceptVisitor<T, S>(IAstVisitor<T, S> visitor, T data)
-			{
-				return visitor.VisitNullNode(this, data);
-			}
-
-			protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
-			{
-				return other == null || other.IsNull;
-			}
-		}
-		#endregion
-
 		public CSharpTokenNode LBraceToken {
 			get { return GetChildByRole(Roles.LBrace); }
 		}

ICSharpCode.Decompiler/CSharp/Syntax/Expressions/Expression.cs

@@ -17,7 +17,6 @@
 // DEALINGS IN THE SOFTWARE.
 
 using System;
-using System.Collections.Generic;
 
 namespace ICSharpCode.Decompiler.CSharp.Syntax
 {
@@ -31,39 +30,6 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 	[DecompilerAstNode(true)]
 	public abstract partial class Expression : AstNode
 	{
-		#region Null
-		public new static readonly Expression Null = new NullExpression();
-
-		sealed class NullExpression : Expression
-		{
-			public override bool IsNull {
-				get {
-					return true;
-				}
-			}
-
-			public override void AcceptVisitor(IAstVisitor visitor)
-			{
-				visitor.VisitNullNode(this);
-			}
-
-			public override T AcceptVisitor<T>(IAstVisitor<T> visitor)
-			{
-				return visitor.VisitNullNode(this);
-			}
-
-			public override S AcceptVisitor<T, S>(IAstVisitor<T, S> visitor, T data)
-			{
-				return visitor.VisitNullNode(this, data);
-			}
-
-			protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
-			{
-				return other == null || other.IsNull;
-			}
-		}
-		#endregion
-
 		#region PatternPlaceholder
 		public static implicit operator Expression(PatternMatching.Pattern pattern)
 		{

ICSharpCode.Decompiler/CSharp/Syntax/Expressions/InterpolatedStringExpression.cs

@@ -1,6 +1,4 @@
-using System;
-using System.Collections.Generic;
-using System.Text;
+using System.Collections.Generic;
 
 using ICSharpCode.Decompiler.CSharp.Syntax.PatternMatching;
 
@@ -51,39 +49,6 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 	[DecompilerAstNode(true)]
 	public abstract partial class InterpolatedStringContent : AstNode
 	{
-		#region Null
-		public new static readonly InterpolatedStringContent Null = new NullInterpolatedStringContent();
-
-		sealed class NullInterpolatedStringContent : InterpolatedStringContent
-		{
-			public override bool IsNull {
-				get {
-					return true;
-				}
-			}
-
-			public override void AcceptVisitor(IAstVisitor visitor)
-			{
-				visitor.VisitNullNode(this);
-			}
-
-			public override T AcceptVisitor<T>(IAstVisitor<T> visitor)
-			{
-				return visitor.VisitNullNode(this);
-			}
-
-			public override S AcceptVisitor<T, S>(IAstVisitor<T, S> visitor, T data)
-			{
-				return visitor.VisitNullNode(this, data);
-			}
-
-			protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
-			{
-				return other == null || other.IsNull;
-			}
-		}
-		#endregion
-
 		public new static readonly Role<InterpolatedStringContent> Role = new Role<InterpolatedStringContent>("InterpolatedStringContent", Syntax.InterpolatedStringContent.Null);
 
 		public override NodeType NodeType => NodeType.Unknown;

ICSharpCode.Decompiler/CSharp/Syntax/Expressions/QueryExpression.cs

@@ -23,39 +23,6 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 	{
 		public static readonly Role<QueryClause> ClauseRole = new Role<QueryClause>("Clause", null);
 
-		#region Null
-		public new static readonly QueryExpression Null = new NullQueryExpression();
-
-		sealed class NullQueryExpression : QueryExpression
-		{
-			public override bool IsNull {
-				get {
-					return true;
-				}
-			}
-
-			public override void AcceptVisitor(IAstVisitor visitor)
-			{
-				visitor.VisitNullNode(this);
-			}
-
-			public override T AcceptVisitor<T>(IAstVisitor<T> visitor)
-			{
-				return visitor.VisitNullNode(this);
-			}
-
-			public override S AcceptVisitor<T, S>(IAstVisitor<T, S> visitor, T data)
-			{
-				return visitor.VisitNullNode(this, data);
-			}
-
-			protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
-			{
-				return other == null || other.IsNull;
-			}
-		}
-		#endregion
-
 		public AstNodeCollection<QueryClause> Clauses {
 			get { return GetChildrenByRole(ClauseRole); }
 		}

ICSharpCode.Decompiler/CSharp/Syntax/Identifier.cs

@@ -31,36 +31,6 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 	[DecompilerAstNode(true)]
 	public partial class Identifier : AstNode
 	{
-		public new static readonly Identifier Null = new NullIdentifier();
-		sealed class NullIdentifier : Identifier
-		{
-			public override bool IsNull {
-				get {
-					return true;
-				}
-			}
-
-			public override void AcceptVisitor(IAstVisitor visitor)
-			{
-				visitor.VisitNullNode(this);
-			}
-
-			public override T AcceptVisitor<T>(IAstVisitor<T> visitor)
-			{
-				return visitor.VisitNullNode(this);
-			}
-
-			public override S AcceptVisitor<T, S>(IAstVisitor<T, S> visitor, T data)
-			{
-				return visitor.VisitNullNode(this, data);
-			}
-
-			protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
-			{
-				return other == null || other.IsNull;
-			}
-		}
-
 		public override NodeType NodeType {
 			get {
 				return NodeType.Token;

ICSharpCode.Decompiler/CSharp/Syntax/SimpleType.cs

@@ -35,44 +35,6 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 	[DecompilerAstNode(true)]
 	public partial class SimpleType : AstType
 	{
-		#region Null
-		public new static readonly SimpleType Null = new NullSimpleType();
-
-		sealed class NullSimpleType : SimpleType
-		{
-			public override bool IsNull {
-				get {
-					return true;
-				}
-			}
-
-			public override void AcceptVisitor(IAstVisitor visitor)
-			{
-				visitor.VisitNullNode(this);
-			}
-
-			public override T AcceptVisitor<T>(IAstVisitor<T> visitor)
-			{
-				return visitor.VisitNullNode(this);
-			}
-
-			public override S AcceptVisitor<T, S>(IAstVisitor<T, S> visitor, T data)
-			{
-				return visitor.VisitNullNode(this, data);
-			}
-
-			protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
-			{
-				return other == null || other.IsNull;
-			}
-
-			public override ITypeReference ToTypeReference(NameLookupMode lookupMode, InterningProvider interningProvider)
-			{
-				return SpecialType.UnknownType;
-			}
-		}
-		#endregion
-
 		public SimpleType()
 		{
 		}

ICSharpCode.Decompiler/CSharp/Syntax/Statements/BlockStatement.cs

@@ -36,38 +36,6 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 	{
 		public static readonly Role<Statement> StatementRole = new Role<Statement>("Statement", Statement.Null);
 
-		#region Null
-		public static readonly new BlockStatement Null = new NullBlockStatement();
-		sealed class NullBlockStatement : BlockStatement
-		{
-			public override bool IsNull {
-				get {
-					return true;
-				}
-			}
-
-			public override void AcceptVisitor(IAstVisitor visitor)
-			{
-				visitor.VisitNullNode(this);
-			}
-
-			public override T AcceptVisitor<T>(IAstVisitor<T> visitor)
-			{
-				return visitor.VisitNullNode(this);
-			}
-
-			public override S AcceptVisitor<T, S>(IAstVisitor<T, S> visitor, T data)
-			{
-				return visitor.VisitNullNode(this, data);
-			}
-
-			protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
-			{
-				return other == null || other.IsNull;
-			}
-		}
-		#endregion
-
 		#region PatternPlaceholder
 		public static implicit operator BlockStatement(PatternMatching.Pattern pattern)
 		{

ICSharpCode.Decompiler/CSharp/Syntax/Statements/Statement.cs

@@ -30,39 +30,6 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 	[DecompilerAstNode(true)]
 	public abstract partial class Statement : AstNode
 	{
-		#region Null
-		public new static readonly Statement Null = new NullStatement();
-
-		sealed class NullStatement : Statement
-		{
-			public override bool IsNull {
-				get {
-					return true;
-				}
-			}
-
-			public override void AcceptVisitor(IAstVisitor visitor)
-			{
-				visitor.VisitNullNode(this);
-			}
-
-			public override T AcceptVisitor<T>(IAstVisitor<T> visitor)
-			{
-				return visitor.VisitNullNode(this);
-			}
-
-			public override S AcceptVisitor<T, S>(IAstVisitor<T, S> visitor, T data)
-			{
-				return visitor.VisitNullNode(this, data);
-			}
-
-			protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
-			{
-				return other == null || other.IsNull;
-			}
-		}
-		#endregion
-
 		#region PatternPlaceholder
 		public static implicit operator Statement(PatternMatching.Pattern pattern)
 		{

ICSharpCode.Decompiler/CSharp/Syntax/Statements/TryCatchStatement.cs

@@ -95,39 +95,6 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 		public static readonly TokenRole CondLPar = new TokenRole("(");
 		public static readonly TokenRole CondRPar = new TokenRole(")");
 
-		#region Null
-		public new static readonly CatchClause Null = new NullCatchClause();
-
-		sealed class NullCatchClause : CatchClause
-		{
-			public override bool IsNull {
-				get {
-					return true;
-				}
-			}
-
-			public override void AcceptVisitor(IAstVisitor visitor)
-			{
-				visitor.VisitNullNode(this);
-			}
-
-			public override T AcceptVisitor<T>(IAstVisitor<T> visitor)
-			{
-				return visitor.VisitNullNode(this);
-			}
-
-			public override S AcceptVisitor<T, S>(IAstVisitor<T, S> visitor, T data)
-			{
-				return visitor.VisitNullNode(this, data);
-			}
-
-			protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
-			{
-				return other == null || other.IsNull;
-			}
-		}
-		#endregion
-
 		#region PatternPlaceholder
 		public static implicit operator CatchClause(PatternMatching.Pattern pattern)
 		{

ICSharpCode.Decompiler/CSharp/Syntax/TupleAstType.cs

@@ -66,39 +66,6 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 	[DecompilerAstNode(true)]
 	public partial class TupleTypeElement : AstNode
 	{
-		#region Null
-		public new static readonly TupleTypeElement Null = new TupleTypeElement();
-
-		sealed class NullTupleTypeElement : TupleTypeElement
-		{
-			public override bool IsNull {
-				get {
-					return true;
-				}
-			}
-
-			public override void AcceptVisitor(IAstVisitor visitor)
-			{
-				visitor.VisitNullNode(this);
-			}
-
-			public override T AcceptVisitor<T>(IAstVisitor<T> visitor)
-			{
-				return visitor.VisitNullNode(this);
-			}
-
-			public override S AcceptVisitor<T, S>(IAstVisitor<T, S> visitor, T data)
-			{
-				return visitor.VisitNullNode(this, data);
-			}
-
-			protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
-			{
-				return other == null || other.IsNull;
-			}
-		}
-		#endregion
-
 		public AstType Type {
 			get { return GetChildByRole(Roles.Type); }
 			set { SetChildByRole(Roles.Type, value); }

ICSharpCode.Decompiler/CSharp/Syntax/TypeMembers/Accessor.cs

@@ -34,36 +34,6 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 	[DecompilerAstNode(true)]
 	public partial class Accessor : EntityDeclaration
 	{
-		public static readonly new Accessor Null = new NullAccessor();
-		sealed class NullAccessor : Accessor
-		{
-			public override bool IsNull {
-				get {
-					return true;
-				}
-			}
-
-			public override void AcceptVisitor(IAstVisitor visitor)
-			{
-				visitor.VisitNullNode(this);
-			}
-
-			public override T AcceptVisitor<T>(IAstVisitor<T> visitor)
-			{
-				return visitor.VisitNullNode(this);
-			}
-
-			public override S AcceptVisitor<T, S>(IAstVisitor<T, S> visitor, T data)
-			{
-				return visitor.VisitNullNode(this, data);
-			}
-
-			protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
-			{
-				return other == null || other.IsNull;
-			}
-		}
-
 		public override NodeType NodeType {
 			get { return NodeType.Unknown; }
 		}

ICSharpCode.Decompiler/CSharp/Syntax/TypeMembers/ConstructorDeclaration.cs

@@ -99,42 +99,6 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 		public static readonly TokenRole BaseKeywordRole = new TokenRole("base");
 		public static readonly TokenRole ThisKeywordRole = new TokenRole("this");
 
-		public static readonly new ConstructorInitializer Null = new NullConstructorInitializer();
-		class NullConstructorInitializer : ConstructorInitializer
-		{
-			public override NodeType NodeType {
-				get {
-					return NodeType.Unknown;
-				}
-			}
-
-			public override bool IsNull {
-				get {
-					return true;
-				}
-			}
-
-			public override void AcceptVisitor(IAstVisitor visitor)
-			{
-				visitor.VisitNullNode(this);
-			}
-
-			public override T AcceptVisitor<T>(IAstVisitor<T> visitor)
-			{
-				return visitor.VisitNullNode(this);
-			}
-
-			public override S AcceptVisitor<T, S>(IAstVisitor<T, S> visitor, T data)
-			{
-				return visitor.VisitNullNode(this, data);
-			}
-
-			protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
-			{
-				return other == null || other.IsNull;
-			}
-		}
-
 		public override NodeType NodeType {
 			get {
 				return NodeType.Unknown;

ICSharpCode.Decompiler/CSharp/Syntax/TypeMembers/VariableInitializer.cs

@@ -30,39 +30,6 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 	[DecompilerAstNode(true)]
 	public partial class VariableInitializer : AstNode
 	{
-		#region Null
-		public new static readonly VariableInitializer Null = new NullVariableInitializer();
-
-		sealed class NullVariableInitializer : VariableInitializer
-		{
-			public override bool IsNull {
-				get {
-					return true;
-				}
-			}
-
-			public override void AcceptVisitor(IAstVisitor visitor)
-			{
-				visitor.VisitNullNode(this);
-			}
-
-			public override T AcceptVisitor<T>(IAstVisitor<T> visitor)
-			{
-				return visitor.VisitNullNode(this);
-			}
-
-			public override S AcceptVisitor<T, S>(IAstVisitor<T, S> visitor, T data)
-			{
-				return visitor.VisitNullNode(this, data);
-			}
-
-			protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
-			{
-				return other == null || other.IsNull;
-			}
-		}
-		#endregion
-
 		#region PatternPlaceholder
 		public static implicit operator VariableInitializer(PatternMatching.Pattern pattern)
 		{

ICSharpCode.Decompiler/CSharp/Syntax/VariableDesignation.cs

@@ -24,40 +24,6 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 	public abstract partial class VariableDesignation : AstNode
 	{
 		public override NodeType NodeType => NodeType.Unknown;
-
-		#region Null
-		public new static readonly VariableDesignation Null = new NullVariableDesignation();
-
-		sealed class NullVariableDesignation : VariableDesignation
-		{
-			public override bool IsNull {
-				get {
-					return true;
-				}
-			}
-
-			public override void AcceptVisitor(IAstVisitor visitor)
-			{
-				visitor.VisitNullNode(this);
-			}
-
-			public override T AcceptVisitor<T>(IAstVisitor<T> visitor)
-			{
-				return visitor.VisitNullNode(this);
-			}
-
-			public override S AcceptVisitor<T, S>(IAstVisitor<T, S> visitor, T data)
-			{
-				return visitor.VisitNullNode(this, data);
-			}
-
-			protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
-			{
-				return other == null || other.IsNull;
-			}
-		}
-		#endregion
-
 	}
 
 	/// <summary>