focus on CS8765

.editorconfig

@@ -149,4 +149,11 @@ dotnet_naming_rule.private_fields_rule.symbols = private_fields_symbols
 dotnet_diagnostic.MEF006.severity = silent
 
 
-dotnet_diagnostic.IDE2003.severity = silent
+dotnet_diagnostic.IDE2003.severity = silent
+
+#cleared null error types
+dotnet_diagnostic.CS8765.severity = error
+dotnet_diagnostic.CS8766.severity = error
+dotnet_diagnostic.CS8767.severity = error
+dotnet_diagnostic.CS8768.severity = error
+dotnet_diagnostic.CS8769.severity = error

ICSharpCode.Decompiler/CSharp/Resolver/CSharpConversions.cs

@@ -77,7 +77,7 @@ namespace ICSharpCode.Decompiler.CSharp.Resolver
 				this.ToType = toType;
 			}
 
-			public override bool Equals(object obj)
+			public override bool Equals(object? obj)
 			{
 				return (obj is TypePair) && Equals((TypePair)obj);
 			}

ICSharpCode.Decompiler/CSharp/Syntax/AstNodeCollection.cs

@@ -200,7 +200,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return node.GetHashCode() ^ role.GetHashCode();
 		}
 
-		public override bool Equals(object obj)
+		public override bool Equals(object? obj)
 		{
 			AstNodeCollection<T>? other = obj as AstNodeCollection<T>;
 			if (other == null)

ICSharpCode.Decompiler/CSharp/Syntax/AstType.cs

@@ -56,12 +56,12 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 				return visitor.VisitNullNode(this, data);
 			}
 
-			protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+			protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 			{
 				return other == null || other.IsNull;
 			}
 
-			public override ITypeReference ToTypeReference(NameLookupMode lookupMode, InterningProvider interningProvider)
+			public override ITypeReference ToTypeReference(NameLookupMode lookupMode, InterningProvider? interningProvider)
 			{
 				return SpecialType.UnknownType;
 			}
@@ -102,12 +102,12 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 				return visitor.VisitPatternPlaceholder(this, child, data);
 			}
 
-			public override ITypeReference ToTypeReference(NameLookupMode lookupMode, InterningProvider interningProvider)
+			public override ITypeReference ToTypeReference(NameLookupMode lookupMode, InterningProvider? interningProvider)
 			{
 				throw new NotSupportedException();
 			}
 
-			protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+			protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 			{
 				return child.DoMatch(other, match);
 			}

ICSharpCode.Decompiler/CSharp/Syntax/CSharpModifierToken.cs

@@ -49,12 +49,12 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			}
 		}
 
-		public override string ToString(CSharpFormattingOptions formattingOptions)
+		public override string ToString(CSharpFormattingOptions? formattingOptions)
 		{
 			return GetModifierName(Modifier);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			CSharpModifierToken? o = other as CSharpModifierToken;
 			return o != null && this.modifier == o.modifier;

ICSharpCode.Decompiler/CSharp/Syntax/CSharpTokenNode.cs

@@ -64,7 +64,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 				return visitor.VisitNullNode(this, data);
 			}
 
-			protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+			protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 			{
 				return other == null || other.IsNull;
 			}
@@ -107,7 +107,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 				this.flags |= role.Index << AstNodeFlagsUsedBits;
 		}
 
-		public override string ToString(CSharpFormattingOptions formattingOptions)
+		public override string ToString(CSharpFormattingOptions? formattingOptions)
 		{
 			uint tokenRoleIndex = (this.flags >> AstNodeFlagsUsedBits);
 			if (Role.GetByIndex(tokenRoleIndex) is TokenRole r)
@@ -132,7 +132,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitCSharpTokenNode(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			CSharpTokenNode? o = other as CSharpTokenNode;
 			return o != null && !o.IsNull && !(o is CSharpModifierToken);

ICSharpCode.Decompiler/CSharp/Syntax/ComposedType.cs

@@ -144,7 +144,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitComposedType(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			ComposedType? o = other as ComposedType;
 			return o != null
@@ -156,7 +156,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 				&& this.ArraySpecifiers.DoMatch(o.ArraySpecifiers, match);
 		}
 
-		public override string ToString(CSharpFormattingOptions formattingOptions)
+		public override string ToString(CSharpFormattingOptions? formattingOptions)
 		{
 			StringBuilder b = new StringBuilder();
 			if (this.HasRefSpecifier)
@@ -287,13 +287,13 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitArraySpecifier(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			ArraySpecifier? o = other as ArraySpecifier;
 			return o != null && this.Dimensions == o.Dimensions;
 		}
 
-		public override string ToString(CSharpFormattingOptions formattingOptions)
+		public override string ToString(CSharpFormattingOptions? formattingOptions)
 		{
 			return "[" + new string(',', this.Dimensions - 1) + "]";
 		}

ICSharpCode.Decompiler/CSharp/Syntax/DocumentationReference.cs

@@ -109,7 +109,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			get { return GetChildrenByRole(Roles.Parameter); }
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			DocumentationReference? o = other as DocumentationReference;
 			if (!(o != null && this.SymbolKind == o.SymbolKind && this.HasParameterList == o.HasParameterList))

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

@@ -109,7 +109,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitAnonymousMethodExpression(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			AnonymousMethodExpression? o = other as AnonymousMethodExpression;
 			return o != null && this.IsAsync == o.IsAsync && this.HasParameterList == o.HasParameterList

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

@@ -81,7 +81,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitAnonymousTypeCreateExpression(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			var o = other as AnonymousTypeCreateExpression;
 			return o != null && this.Initializers.DoMatch(o.Initializers, match);

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

@@ -69,7 +69,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitArrayCreateExpression(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			ArrayCreateExpression? o = other as ArrayCreateExpression;
 			return o != null && this.Type.DoMatch(o.Type, match)

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

@@ -85,7 +85,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 				return visitor.VisitNullNode(this, data);
 			}
 
-			protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+			protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 			{
 				return other == null || other.IsNull;
 			}
@@ -119,7 +119,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitArrayInitializerExpression(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			ArrayInitializerExpression? o = other as ArrayInitializerExpression;
 			return o != null && this.Elements.DoMatch(o.Elements, match);
@@ -176,7 +176,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 				return visitor.VisitPatternPlaceholder(this, child, data);
 			}
 
-			protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+			protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 			{
 				return child.DoMatch(other, match);
 			}

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

@@ -73,7 +73,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitAsExpression(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			AsExpression? o = other as AsExpression;
 			return o != null && this.Expression.DoMatch(o.Expression, match) && this.Type.DoMatch(o.Type, match);

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

@@ -103,7 +103,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitAssignmentExpression(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			AssignmentExpression? o = other as AssignmentExpression;
 			return o != null && (this.Operator == AssignmentOperatorType.Any || this.Operator == o.Operator)

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

@@ -63,7 +63,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitBaseReferenceExpression(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			BaseReferenceExpression? o = other as BaseReferenceExpression;
 			return o != null;

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

@@ -105,7 +105,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitBinaryOperatorExpression(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			BinaryOperatorExpression? o = other as BinaryOperatorExpression;
 			return o != null && (this.Operator == BinaryOperatorType.Any || this.Operator == o.Operator)

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

@@ -75,7 +75,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitCastExpression(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			CastExpression? o = other as CastExpression;
 			return o != null && this.Type.DoMatch(o.Type, match) && this.Expression.DoMatch(o.Expression, match);

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

@@ -75,7 +75,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitCheckedExpression(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			CheckedExpression? o = other as CheckedExpression;
 			return o != null && this.Expression.DoMatch(o.Expression, match);

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

@@ -87,7 +87,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitConditionalExpression(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			ConditionalExpression? o = other as ConditionalExpression;
 			return o != null && this.Condition.DoMatch(o.Condition, match) && this.TrueExpression.DoMatch(o.TrueExpression, match) && this.FalseExpression.DoMatch(o.FalseExpression, match);

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

@@ -50,7 +50,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitDeclarationExpression(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, Match match)
+		protected internal override bool DoMatch(AstNode? other, Match match)
 		{
 			return other is DeclarationExpression o
 				&& Type.DoMatch(o.Type, match)

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

@@ -75,7 +75,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitDefaultValueExpression(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			DefaultValueExpression? o = other as DefaultValueExpression;
 			return o != null && this.Type.DoMatch(o.Type, match);

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

@@ -93,7 +93,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitDirectionExpression(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			DirectionExpression? o = other as DirectionExpression;
 			return o != null && this.FieldDirection == o.FieldDirection && this.Expression.DoMatch(o.Expression, match);

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

@@ -72,7 +72,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitErrorNode(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			var o = other as ErrorExpression;
 			return o != null;

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

@@ -56,7 +56,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 				return visitor.VisitNullNode(this, data);
 			}
 
-			protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+			protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 			{
 				return other == null || other.IsNull;
 			}
@@ -97,7 +97,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 				return visitor.VisitPatternPlaceholder(this, child, data);
 			}
 
-			protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+			protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 			{
 				return child.DoMatch(other, match);
 			}

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

@@ -79,7 +79,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitIdentifierExpression(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			IdentifierExpression? o = other as IdentifierExpression;
 			return o != null && MatchString(this.Identifier, o.Identifier) && this.TypeArguments.DoMatch(o.TypeArguments, match);

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

@@ -40,7 +40,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitInterpolatedStringExpression(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, Match match)
+		protected internal override bool DoMatch(AstNode? other, Match match)
 		{
 			InterpolatedStringExpression? o = other as InterpolatedStringExpression;
 			return o != null && !o.IsNull && this.Content.DoMatch(o.Content, match);
@@ -75,7 +75,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 				return visitor.VisitNullNode(this, data);
 			}
 
-			protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+			protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 			{
 				return other == null || other.IsNull;
 			}
@@ -139,7 +139,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitInterpolation(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, Match match)
+		protected internal override bool DoMatch(AstNode? other, Match match)
 		{
 			Interpolation? o = other as Interpolation;
 			return o != null && this.Expression.DoMatch(o.Expression, match);
@@ -175,7 +175,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitInterpolatedStringText(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, Match match)
+		protected internal override bool DoMatch(AstNode? other, Match match)
 		{
 			InterpolatedStringText? o = other as InterpolatedStringText;
 			return o != null && o.Text == this.Text;

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

@@ -85,7 +85,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 		{
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			InvocationExpression? o = other as InvocationExpression;
 			return o != null && this.Target.DoMatch(o.Target, match) && this.Arguments.DoMatch(o.Arguments, match);

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

@@ -74,7 +74,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitIsExpression(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			IsExpression? o = other as IsExpression;
 			return o != null && this.Expression.DoMatch(o.Expression, match) && this.Type.DoMatch(o.Type, match);

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

@@ -82,7 +82,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitLambdaExpression(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			LambdaExpression? o = other as LambdaExpression;
 			return o != null && this.IsAsync == o.IsAsync && this.Parameters.DoMatch(o.Parameters, match) && this.Body.DoMatch(o.Body, match);

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

@@ -112,7 +112,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitMemberReferenceExpression(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			MemberReferenceExpression? o = other as MemberReferenceExpression;
 			return o != null && this.Target.DoMatch(o.Target, match) && MatchString(this.MemberName, o.MemberName) && this.TypeArguments.DoMatch(o.TypeArguments, match);

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

@@ -77,7 +77,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitNamedArgumentExpression(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			NamedArgumentExpression? o = other as NamedArgumentExpression;
 			return o != null && MatchString(this.Name, o.Name) && this.Expression.DoMatch(o.Expression, match);

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

@@ -86,7 +86,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitNamedExpression(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			var o = other as NamedExpression;
 			return o != null && MatchString(this.Name, o.Name) && this.Expression.DoMatch(o.Expression, match);

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

@@ -75,7 +75,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitNullReferenceExpression(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			NullReferenceExpression? o = other as NullReferenceExpression;
 			return o != null;

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

@@ -97,7 +97,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitObjectCreateExpression(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			ObjectCreateExpression? o = other as ObjectCreateExpression;
 			return o != null && this.Type.DoMatch(o.Type, match) && this.Arguments.DoMatch(o.Arguments, match) && this.Initializer.DoMatch(o.Initializer, match);

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

@@ -64,7 +64,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitOutVarDeclarationExpression(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			var o = other as OutVarDeclarationExpression;
 			return o != null && this.Type.DoMatch(o.Type, match) && this.Variable.DoMatch(o.Variable, match);

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

@@ -69,7 +69,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitParenthesizedExpression(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			ParenthesizedExpression? o = other as ParenthesizedExpression;
 			return o != null && this.Expression.DoMatch(o.Expression, match);

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

@@ -80,7 +80,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitPointerReferenceExpression(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			PointerReferenceExpression? o = other as PointerReferenceExpression;
 			return o != null && MatchString(this.MemberName, o.MemberName) && this.TypeArguments.DoMatch(o.TypeArguments, match);

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

@@ -143,7 +143,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return new TextLocation(line, col);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			PrimitiveExpression? o = other as PrimitiveExpression;
 			return o != null && (this.Value == AnyValue || object.Equals(this.Value, o.Value));

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

@@ -48,7 +48,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 				return visitor.VisitNullNode(this, data);
 			}
 
-			protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+			protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 			{
 				return other == null || other.IsNull;
 			}
@@ -74,7 +74,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitQueryExpression(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			QueryExpression? o = other as QueryExpression;
 			return o != null && !o.IsNull && this.Clauses.DoMatch(o.Clauses, match);
@@ -148,7 +148,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitQueryContinuationClause(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			QueryContinuationClause? o = other as QueryContinuationClause;
 			return o != null && MatchString(this.Identifier, o.Identifier) && this.PrecedingQuery.DoMatch(o.PrecedingQuery, match);
@@ -206,7 +206,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitQueryFromClause(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			QueryFromClause? o = other as QueryFromClause;
 			return o != null && this.Type.DoMatch(o.Type, match) && MatchString(this.Identifier, o.Identifier)
@@ -259,7 +259,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitQueryLetClause(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			QueryLetClause? o = other as QueryLetClause;
 			return o != null && MatchString(this.Identifier, o.Identifier) && this.Expression.DoMatch(o.Expression, match);
@@ -295,7 +295,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitQueryWhereClause(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			QueryWhereClause? o = other as QueryWhereClause;
 			return o != null && this.Condition.DoMatch(o.Condition, match);
@@ -404,7 +404,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitQueryJoinClause(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			QueryJoinClause? o = other as QueryJoinClause;
 			return o != null && this.IsGroupJoin == o.IsGroupJoin
@@ -443,7 +443,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitQueryOrderClause(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			QueryOrderClause? o = other as QueryOrderClause;
 			return o != null && this.Orderings.DoMatch(o.Orderings, match);
@@ -488,7 +488,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitQueryOrdering(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			QueryOrdering? o = other as QueryOrdering;
 			return o != null && this.Direction == o.Direction && this.Expression.DoMatch(o.Expression, match);
@@ -530,7 +530,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitQuerySelectClause(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			QuerySelectClause? o = other as QuerySelectClause;
 			return o != null && this.Expression.DoMatch(o.Expression, match);
@@ -577,7 +577,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitQueryGroupClause(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			QueryGroupClause? o = other as QueryGroupClause;
 			return o != null && this.Projection.DoMatch(o.Projection, match) && this.Key.DoMatch(o.Key, match);

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

@@ -55,7 +55,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitRecursivePatternExpression(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, Match match)
+		protected internal override bool DoMatch(AstNode? other, Match match)
 		{
 			return other is RecursivePatternExpression o
 				&& Type.DoMatch(o.Type, match)

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

@@ -75,7 +75,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitSizeOfExpression(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			SizeOfExpression? o = other as SizeOfExpression;
 			return o != null && this.Type.DoMatch(o.Type, match);

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

@@ -77,7 +77,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitStackAllocExpression(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			StackAllocExpression? o = other as StackAllocExpression;
 			return o != null && this.Type.DoMatch(o.Type, match)

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

@@ -63,7 +63,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitSwitchExpression(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			SwitchExpression? o = other as SwitchExpression;
 			return o != null && this.Expression.DoMatch(o.Expression, match) && this.SwitchSections.DoMatch(o.SwitchSections, match);
@@ -109,7 +109,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitSwitchExpressionSection(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			SwitchExpressionSection? o = other as SwitchExpressionSection;
 			return o != null && this.Pattern.DoMatch(o.Pattern, match) && this.Body.DoMatch(o.Body, match);

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

@@ -63,7 +63,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitThisReferenceExpression(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			ThisReferenceExpression? o = other as ThisReferenceExpression;
 			return o != null;

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

@@ -58,7 +58,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitThrowExpression(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			ThrowExpression? o = other as ThrowExpression;
 			return o != null && this.Expression.DoMatch(o.Expression, match);

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

@@ -43,7 +43,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitTupleExpression(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, Match match)
+		protected internal override bool DoMatch(AstNode? other, Match match)
 		{
 			return other is TupleExpression tuple
 				&& Elements.DoMatch(tuple.Elements, match);

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

@@ -76,7 +76,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitTypeOfExpression(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			TypeOfExpression? o = other as TypeOfExpression;
 			return o != null && this.Type.DoMatch(o.Type, match);

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

@@ -54,7 +54,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			AddChild(type, Roles.Type);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			TypeReferenceExpression? o = other as TypeReferenceExpression;
 			return o != null && this.Type.DoMatch(o.Type, match);

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

@@ -87,7 +87,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitUnaryOperatorExpression(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			UnaryOperatorExpression? o = other as UnaryOperatorExpression;
 			return o != null && (this.Operator == UnaryOperatorType.Any || this.Operator == o.Operator)

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

@@ -75,7 +75,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitUncheckedExpression(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			UncheckedExpression? o = other as UncheckedExpression;
 			return o != null && this.Expression.DoMatch(o.Expression, match);

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

@@ -95,7 +95,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitUndocumentedExpression(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			UndocumentedExpression? o = other as UndocumentedExpression;
 			return o != null && this.UndocumentedExpressionType == o.UndocumentedExpressionType && this.Arguments.DoMatch(o.Arguments, match);

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

@@ -57,7 +57,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitWithInitializerExpression(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, Match match)
+		protected internal override bool DoMatch(AstNode? other, Match match)
 		{
 			return other is WithInitializerExpression o
 				&& this.Expression.DoMatch(o.Expression, match)

ICSharpCode.Decompiler/CSharp/Syntax/FunctionPointerAstType.cs

@@ -66,7 +66,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitFunctionPointerType(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			return other is FunctionPointerAstType o
 				&& this.CallingConventions.DoMatch(o.CallingConventions, match)

ICSharpCode.Decompiler/CSharp/Syntax/GeneralScope/Attribute.cs

@@ -77,13 +77,13 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitAttribute(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			Attribute? o = other as Attribute;
 			return o != null && this.Type.DoMatch(o.Type, match) && this.Arguments.DoMatch(o.Arguments, match);
 		}
 
-		public override string ToString(CSharpFormattingOptions formattingOptions)
+		public override string ToString(CSharpFormattingOptions? formattingOptions)
 		{
 			if (IsNull)
 				return "Null";

ICSharpCode.Decompiler/CSharp/Syntax/GeneralScope/AttributeSection.cs

@@ -66,7 +66,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 				return visitor.VisitPatternPlaceholder(this, child, data);
 			}
 
-			protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+			protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 			{
 				return child.DoMatch(other, match);
 			}
@@ -129,7 +129,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitAttributeSection(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			AttributeSection? o = other as AttributeSection;
 			return o != null && MatchString(this.AttributeTarget, o.AttributeTarget) && this.Attributes.DoMatch(o.Attributes, match);

ICSharpCode.Decompiler/CSharp/Syntax/GeneralScope/Comment.cs

@@ -143,7 +143,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitComment(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			Comment? o = other as Comment;
 			return o != null && this.CommentType == o.CommentType && MatchString(this.Content, o.Content);

ICSharpCode.Decompiler/CSharp/Syntax/GeneralScope/Constraint.cs

@@ -73,7 +73,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitConstraint(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			Constraint? o = other as Constraint;
 			return o != null && this.TypeParameter.DoMatch(o.TypeParameter, match) && this.BaseTypes.DoMatch(o.BaseTypes, match);

ICSharpCode.Decompiler/CSharp/Syntax/GeneralScope/DelegateDeclaration.cs

@@ -80,7 +80,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitDelegateDeclaration(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			DelegateDeclaration? o = other as DelegateDeclaration;
 			return o != null && MatchString(this.Name, o.Name)

ICSharpCode.Decompiler/CSharp/Syntax/GeneralScope/ExternAliasDeclaration.cs

@@ -83,7 +83,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitExternAliasDeclaration(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			var o = other as ExternAliasDeclaration;
 			return o != null && MatchString(this.Name, o.Name);

ICSharpCode.Decompiler/CSharp/Syntax/GeneralScope/NamespaceDeclaration.cs

@@ -150,7 +150,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitNamespaceDeclaration(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			NamespaceDeclaration? o = other as NamespaceDeclaration;
 			return o != null && MatchString(this.Name, o.Name) && this.Members.DoMatch(o.Members, match);

ICSharpCode.Decompiler/CSharp/Syntax/GeneralScope/PreProcessorDirective.cs

@@ -193,7 +193,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitPreProcessorDirective(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			PreProcessorDirective? o = other as PreProcessorDirective;
 			return o != null && Type == o.Type && MatchString(Argument, o.Argument);

ICSharpCode.Decompiler/CSharp/Syntax/GeneralScope/TypeDeclaration.cs

@@ -147,7 +147,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitTypeDeclaration(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			TypeDeclaration? o = other as TypeDeclaration;
 			return o != null && this.ClassType == o.ClassType && MatchString(this.Name, o.Name)

ICSharpCode.Decompiler/CSharp/Syntax/GeneralScope/TypeParameterDeclaration.cs

@@ -104,7 +104,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitTypeParameterDeclaration(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			TypeParameterDeclaration? o = other as TypeParameterDeclaration;
 			return o != null && this.Variance == o.Variance && MatchString(this.Name, o.Name) && this.Attributes.DoMatch(o.Attributes, match);

ICSharpCode.Decompiler/CSharp/Syntax/GeneralScope/UsingAliasDeclaration.cs

@@ -99,7 +99,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitUsingAliasDeclaration(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			UsingAliasDeclaration? o = other as UsingAliasDeclaration;
 			return o != null && MatchString(this.Alias, o.Alias) && this.Import.DoMatch(o.Import, match);

ICSharpCode.Decompiler/CSharp/Syntax/GeneralScope/UsingDeclaration.cs

@@ -115,7 +115,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitUsingDeclaration(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			UsingDeclaration? o = other as UsingDeclaration;
 			return o != null && this.Import.DoMatch(o.Import, match);

ICSharpCode.Decompiler/CSharp/Syntax/Identifier.cs

@@ -54,7 +54,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 				return visitor.VisitNullNode(this, data);
 			}
 
-			protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+			protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 			{
 				return other == null || other.IsNull;
 			}
@@ -164,7 +164,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitIdentifier(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			Identifier? o = other as Identifier;
 			return o != null && !o.IsNull && MatchString(this.Name, o.Name);

ICSharpCode.Decompiler/CSharp/Syntax/InvocationAstType.cs

@@ -55,7 +55,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitInvocationType(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, Match match)
+		protected internal override bool DoMatch(AstNode? other, Match match)
 		{
 			return other is InvocationAstType o
 				&& this.BaseType.DoMatch(o.BaseType, match)

ICSharpCode.Decompiler/CSharp/Syntax/MemberType.cs

@@ -112,7 +112,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitMemberType(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			MemberType? o = other as MemberType;
 			return o != null && this.IsDoubleColon == o.IsDoubleColon

ICSharpCode.Decompiler/CSharp/Syntax/PatternMatching/Pattern.cs

@@ -31,7 +31,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax.PatternMatching
 		/// </summary>
 		public static readonly string AnyString = "$any$";
 
-		public static bool MatchString(string pattern, string text)
+		public static bool MatchString(string? pattern, string? text)
 		{
 			return pattern == AnyString || pattern == text;
 		}

ICSharpCode.Decompiler/CSharp/Syntax/PrimitiveType.cs

@@ -100,13 +100,13 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitPrimitiveType(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			PrimitiveType? o = other as PrimitiveType;
 			return o != null && MatchString(this.Keyword, o.Keyword);
 		}
 
-		public override string ToString(CSharpFormattingOptions formattingOptions)
+		public override string ToString(CSharpFormattingOptions? formattingOptions)
 		{
 			return Keyword;
 		}

ICSharpCode.Decompiler/CSharp/Syntax/SimpleType.cs

@@ -60,12 +60,12 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 				return visitor.VisitNullNode(this, data);
 			}
 
-			protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+			protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 			{
 				return other == null || other.IsNull;
 			}
 
-			public override ITypeReference ToTypeReference(NameLookupMode lookupMode, InterningProvider interningProvider)
+			public override ITypeReference ToTypeReference(NameLookupMode lookupMode, InterningProvider? interningProvider)
 			{
 				return SpecialType.UnknownType;
 			}
@@ -141,7 +141,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitSimpleType(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			SimpleType? o = other as SimpleType;
 			return o != null && MatchString(this.Identifier, o.Identifier) && this.TypeArguments.DoMatch(o.TypeArguments, match);

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

@@ -60,7 +60,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 				return visitor.VisitNullNode(this, data);
 			}
 
-			protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+			protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 			{
 				return other == null || other.IsNull;
 			}
@@ -101,7 +101,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 				return visitor.VisitPatternPlaceholder(this, child, data);
 			}
 
-			protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+			protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 			{
 				return child.DoMatch(other, match);
 			}
@@ -140,7 +140,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitBlockStatement(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			BlockStatement? o = other as BlockStatement;
 			return o != null && !o.IsNull && this.Statements.DoMatch(o.Statements, match);

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

@@ -57,7 +57,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitBreakStatement(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			BreakStatement? o = other as BreakStatement;
 			return o != null;

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

@@ -67,7 +67,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitCheckedStatement(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			CheckedStatement? o = other as CheckedStatement;
 			return o != null && this.Body.DoMatch(o.Body, match);

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

@@ -57,7 +57,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitContinueStatement(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			ContinueStatement? o = other as ContinueStatement;
 			return o != null;

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

@@ -80,7 +80,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitDoWhileStatement(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			DoWhileStatement? o = other as DoWhileStatement;
 			return o != null && this.EmbeddedStatement.DoMatch(o.EmbeddedStatement, match) && this.Condition.DoMatch(o.Condition, match);

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

@@ -64,7 +64,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitEmptyStatement(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			EmptyStatement? o = other as EmptyStatement;
 			return o != null;

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

@@ -65,7 +65,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			this.Expression = expression;
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			ExpressionStatement? o = other as ExpressionStatement;
 			return o != null && this.Expression.DoMatch(o.Expression, match);

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

@@ -75,7 +75,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitFixedStatement(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			FixedStatement? o = other as FixedStatement;
 			return o != null && this.Type.DoMatch(o.Type, match) && this.Variables.DoMatch(o.Variables, match) && this.EmbeddedStatement.DoMatch(o.EmbeddedStatement, match);

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

@@ -86,7 +86,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitForStatement(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			ForStatement? o = other as ForStatement;
 			return o != null && this.Initializers.DoMatch(o.Initializers, match) && this.Condition.DoMatch(o.Condition, match)

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

@@ -96,7 +96,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitForeachStatement(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			ForeachStatement? o = other as ForeachStatement;
 			return o != null && this.VariableType.DoMatch(o.VariableType, match) && this.VariableDesignation.DoMatch(o.VariableDesignation, match)

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

@@ -78,7 +78,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitGotoStatement(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			GotoStatement? o = other as GotoStatement;
 			return o != null && MatchString(this.Label, o.Label);
@@ -128,7 +128,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitGotoCaseStatement(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			GotoCaseStatement? o = other as GotoCaseStatement;
 			return o != null && this.LabelExpression.DoMatch(o.LabelExpression, match);
@@ -170,7 +170,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitGotoDefaultStatement(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			GotoDefaultStatement? o = other as GotoDefaultStatement;
 			return o != null;

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

@@ -84,7 +84,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitIfElseStatement(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			IfElseStatement? o = other as IfElseStatement;
 			return o != null && this.Condition.DoMatch(o.Condition, match) && this.TrueStatement.DoMatch(o.TrueStatement, match) && this.FalseStatement.DoMatch(o.FalseStatement, match);

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

@@ -65,7 +65,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitLabelStatement(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			LabelStatement? o = other as LabelStatement;
 			return o != null && MatchString(this.Label, o.Label);

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

@@ -49,7 +49,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitLocalFunctionDeclarationStatement(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, Match match)
+		protected internal override bool DoMatch(AstNode? other, Match match)
 		{
 			return other is LocalFunctionDeclarationStatement o && Declaration.DoMatch(o.Declaration, match);
 		}

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

@@ -71,7 +71,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitLockStatement(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			LockStatement? o = other as LockStatement;
 			return o != null && this.Expression.DoMatch(o.Expression, match) && this.EmbeddedStatement.DoMatch(o.EmbeddedStatement, match);

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

@@ -71,7 +71,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitReturnStatement(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			ReturnStatement? o = other as ReturnStatement;
 			return o != null && this.Expression.DoMatch(o.Expression, match);

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

@@ -55,7 +55,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 				return visitor.VisitNullNode(this, data);
 			}
 
-			protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+			protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 			{
 				return other == null || other.IsNull;
 			}
@@ -96,7 +96,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 				return visitor.VisitPatternPlaceholder(this, child, data);
 			}
 
-			protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+			protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 			{
 				return child.DoMatch(other, match);
 			}

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

@@ -79,7 +79,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitSwitchStatement(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			SwitchStatement? o = other as SwitchStatement;
 			return o != null && this.Expression.DoMatch(o.Expression, match) && this.SwitchSections.DoMatch(o.SwitchSections, match);
@@ -122,7 +122,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 				return visitor.VisitPatternPlaceholder(this, child, data);
 			}
 
-			protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+			protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 			{
 				return child.DoMatch(other, match);
 			}
@@ -165,7 +165,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitSwitchSection(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			SwitchSection? o = other as SwitchSection;
 			return o != null && this.CaseLabels.DoMatch(o.CaseLabels, match) && this.Statements.DoMatch(o.Statements, match);
@@ -219,7 +219,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitCaseLabel(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			CaseLabel? o = other as CaseLabel;
 			return o != null && this.Expression.DoMatch(o.Expression, match);

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

@@ -71,7 +71,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitThrowStatement(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			ThrowStatement? o = other as ThrowStatement;
 			return o != null && this.Expression.DoMatch(o.Expression, match);

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

@@ -75,7 +75,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitTryCatchStatement(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			TryCatchStatement? o = other as TryCatchStatement;
 			return o != null && this.TryBlock.DoMatch(o.TryBlock, match) && this.CatchClauses.DoMatch(o.CatchClauses, match) && this.FinallyBlock.DoMatch(o.FinallyBlock, match);
@@ -119,7 +119,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 				return visitor.VisitNullNode(this, data);
 			}
 
-			protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+			protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 			{
 				return other == null || other.IsNull;
 			}
@@ -160,7 +160,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 				return visitor.VisitPatternPlaceholder(this, child, data);
 			}
 
-			protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+			protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 			{
 				return child.DoMatch(other, match);
 			}
@@ -251,7 +251,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitCatchClause(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			CatchClause? o = other as CatchClause;
 			return o != null && this.Type.DoMatch(o.Type, match) && MatchString(this.VariableName, o.VariableName) && this.Body.DoMatch(o.Body, match);

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

@@ -67,7 +67,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitUncheckedStatement(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			UncheckedStatement? o = other as UncheckedStatement;
 			return o != null && this.Body.DoMatch(o.Body, match);

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

@@ -58,7 +58,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitUnsafeStatement(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			UnsafeStatement? o = other as UnsafeStatement;
 			return o != null && this.Body.DoMatch(o.Body, match);

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

@@ -87,7 +87,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitUsingStatement(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			UsingStatement? o = other as UsingStatement;
 			return o != null && this.IsAsync == o.IsAsync && this.ResourceAcquisition.DoMatch(o.ResourceAcquisition, match) && this.EmbeddedStatement.DoMatch(o.EmbeddedStatement, match);

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

@@ -79,7 +79,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitVariableDeclarationStatement(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			VariableDeclarationStatement? o = other as VariableDeclarationStatement;
 			return o != null && this.Modifiers == o.Modifiers && this.Type.DoMatch(o.Type, match) && this.Variables.DoMatch(o.Variables, match);

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

@@ -71,7 +71,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitWhileStatement(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			WhileStatement? o = other as WhileStatement;
 			return o != null && this.Condition.DoMatch(o.Condition, match) && this.EmbeddedStatement.DoMatch(o.EmbeddedStatement, match);

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

@@ -62,7 +62,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitYieldBreakStatement(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			YieldBreakStatement? o = other as YieldBreakStatement;
 			return o != null;

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

@@ -67,7 +67,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return visitor.VisitYieldReturnStatement(this, data);
 		}
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			YieldReturnStatement? o = other as YieldReturnStatement;
 			return o != null && this.Expression.DoMatch(o.Expression, match);

ICSharpCode.Decompiler/CSharp/Syntax/SyntaxTree.cs

@@ -117,7 +117,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 		}
 
 
-		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
+		protected internal override bool DoMatch(AstNode? other, PatternMatching.Match match)
 		{
 			SyntaxTree? o = other as SyntaxTree;
 			return o != null && this.Members.DoMatch(o.Members, match);

ICSharpCode.Decompiler/CSharp/Syntax/TextLocation.cs

@@ -98,7 +98,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 		/// <summary>
 		/// Equality test.
 		/// </summary>
-		public override bool Equals(object obj)
+		public override bool Equals(object? obj)
 		{
 			if (!(obj is TextLocation))
 				return false;
@@ -187,17 +187,17 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 
 	public class TextLocationConverter : TypeConverter
 	{
-		public override bool CanConvertFrom(ITypeDescriptorContext context, Type sourceType)
+		public override bool CanConvertFrom(ITypeDescriptorContext? context, Type sourceType)
 		{
 			return sourceType == typeof(string) || base.CanConvertFrom(context, sourceType);
 		}
 
-		public override bool CanConvertTo(ITypeDescriptorContext context, Type destinationType)
+		public override bool CanConvertTo(ITypeDescriptorContext? context, Type? destinationType)
 		{
 			return destinationType == typeof(TextLocation) || base.CanConvertTo(context, destinationType);
 		}
 
-		public override object ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, object value)
+		public override object? ConvertFrom(ITypeDescriptorContext? context, CultureInfo? culture, object value)
 		{
 			if (value is string)
 			{
@@ -210,7 +210,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return base.ConvertFrom(context, culture, value);
 		}
 
-		public override object ConvertTo(ITypeDescriptorContext context, CultureInfo culture, object value, Type destinationType)
+		public override object? ConvertTo(ITypeDescriptorContext? context, CultureInfo? culture, object? value, Type destinationType)
 		{
 			if (value is TextLocation)
 			{