Add additional C# AST nodes used for deconstruction.

ICSharpCode.Decompiler/CSharp/OutputVisitor/CSharpOutputVisitor.cs

@@ -791,6 +791,17 @@ namespace ICSharpCode.Decompiler.CSharp.OutputVisitor
 			EndNode(directionExpression);
 		}
 
+		public virtual void VisitDeclarationExpression(DeclarationExpression declarationExpression)
+		{
+			StartNode(declarationExpression);
+
+			declarationExpression.Type.AcceptVisitor(this);
+			Space();
+			declarationExpression.Designation.AcceptVisitor(this);
+
+			EndNode(declarationExpression);
+		}
+
 		public virtual void VisitOutVarDeclarationExpression(OutVarDeclarationExpression outVarDeclarationExpression)
 		{
 			StartNode(outVarDeclarationExpression);
@@ -2391,6 +2402,22 @@ namespace ICSharpCode.Decompiler.CSharp.OutputVisitor
 			EndNode(primitiveType);
 		}
 
+		public virtual void VisitSingleVariableDesignation(SingleVariableDesignation singleVariableDesignation)
+		{
+			StartNode(singleVariableDesignation);
+			writer.WriteIdentifier(singleVariableDesignation.IdentifierToken);
+			EndNode(singleVariableDesignation);
+		}
+
+		public virtual void VisitParenthesizedVariableDesignation(ParenthesizedVariableDesignation parenthesizedVariableDesignation)
+		{
+			StartNode(parenthesizedVariableDesignation);
+			LPar();
+			WriteCommaSeparatedList(parenthesizedVariableDesignation.VariableDesignations);
+			RPar();
+			EndNode(parenthesizedVariableDesignation);
+		}
+
 		public virtual void VisitComment(Comment comment)
 		{
 			writer.StartNode(comment);

ICSharpCode.Decompiler/CSharp/Syntax/DepthFirstAstVisitor.cs

@@ -491,9 +491,14 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			VisitChildren (objectCreateExpression);
 		}
 
-		public virtual void VisitOutVarDeclarationExpression (OutVarDeclarationExpression outVarDeclarationExpression)
+		public virtual void VisitDeclarationExpression(DeclarationExpression declarationExpression)
 		{
-			VisitChildren (outVarDeclarationExpression);
+			VisitChildren(declarationExpression);
+		}
+
+		public virtual void VisitOutVarDeclarationExpression(OutVarDeclarationExpression outVarDeclarationExpression)
+		{
+			VisitChildren(outVarDeclarationExpression);
 		}
 
 		public virtual void VisitAnonymousTypeCreateExpression(AnonymousTypeCreateExpression anonymousTypeCreateExpression)
@@ -656,6 +661,16 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			VisitChildren (namedExpression);
 		}
 
+		public virtual void VisitSingleVariableDesignation(SingleVariableDesignation singleVariableDesignation)
+		{
+			VisitChildren(singleVariableDesignation);
+		}
+
+		public virtual void VisitParenthesizedVariableDesignation(ParenthesizedVariableDesignation parenthesizedVariableDesignation)
+		{
+			VisitChildren(parenthesizedVariableDesignation);
+		}
+
 		public virtual void VisitErrorNode(AstNode errorNode)
 		{
 			VisitChildren(errorNode);
@@ -1133,7 +1148,12 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return VisitChildren (objectCreateExpression);
 		}
 
-		public virtual T VisitOutVarDeclarationExpression (OutVarDeclarationExpression outVarDeclarationExpression)
+		public virtual T VisitDeclarationExpression(DeclarationExpression declarationExpression)
+		{
+			return VisitChildren(declarationExpression);
+		}
+
+		public virtual T VisitOutVarDeclarationExpression(OutVarDeclarationExpression outVarDeclarationExpression)
 		{
 			return VisitChildren(outVarDeclarationExpression);
 		}
@@ -1298,6 +1318,16 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return VisitChildren (namedExpression);
 		}
 
+		public virtual T VisitSingleVariableDesignation(SingleVariableDesignation singleVariableDesignation)
+		{
+			return VisitChildren(singleVariableDesignation);
+		}
+
+		public virtual T VisitParenthesizedVariableDesignation(ParenthesizedVariableDesignation parenthesizedVariableDesignation)
+		{
+			return VisitChildren(parenthesizedVariableDesignation);
+		}
+
 		public virtual T VisitErrorNode(AstNode errorNode)
 		{
 			return VisitChildren(errorNode);
@@ -1775,9 +1805,14 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return VisitChildren (objectCreateExpression, data);
 		}
 
+		public virtual S VisitDeclarationExpression(DeclarationExpression declarationExpression, T data)
+		{
+			return VisitChildren(declarationExpression, data);
+		}
+
 		public virtual S VisitOutVarDeclarationExpression(OutVarDeclarationExpression outVarDeclarationExpression, T data)
 		{
-			return VisitChildren (outVarDeclarationExpression, data);
+			return VisitChildren(outVarDeclarationExpression, data);
 		}
 
 		public virtual S VisitAnonymousTypeCreateExpression(AnonymousTypeCreateExpression anonymousTypeCreateExpression, T data)
@@ -1940,6 +1975,16 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			return VisitChildren (namedExpression, data);
 		}
 
+		public virtual S VisitSingleVariableDesignation(SingleVariableDesignation singleVariableDesignation, T data)
+		{
+			return VisitChildren(singleVariableDesignation, data);
+		}
+
+		public virtual S VisitParenthesizedVariableDesignation(ParenthesizedVariableDesignation parenthesizedVariableDesignation, T data)
+		{
+			return VisitChildren(parenthesizedVariableDesignation, data);
+		}
+
 		public virtual S VisitErrorNode(AstNode errorNode, T data)
 		{
 			return VisitChildren(errorNode, data);

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

@@ -0,0 +1,58 @@
+// Copyright (c) 2020 Siegfried Pammer
+// 
+// Permission is hereby granted, free of charge, to any person obtaining a copy of this
+// software and associated documentation files (the "Software"), to deal in the Software
+// without restriction, including without limitation the rights to use, copy, modify, merge,
+// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
+// to whom the Software is furnished to do so, subject to the following conditions:
+// 
+// The above copyright notice and this permission notice shall be included in all copies or
+// substantial portions of the Software.
+// 
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
+// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+using ICSharpCode.Decompiler.CSharp.Syntax.PatternMatching;
+
+namespace ICSharpCode.Decompiler.CSharp.Syntax
+{
+	/// <summary>
+	/// TypeName VariableDesignation
+	/// </summary>
+	public class DeclarationExpression : Expression
+	{
+		public AstType Type {
+			get { return GetChildByRole(Roles.Type); }
+			set { SetChildByRole(Roles.Type, value); }
+		}
+
+		public VariableDesignation Designation {
+			get { return GetChildByRole(VariableDesignation.Role); }
+			set { SetChildByRole(VariableDesignation.Role, value); }
+		}
+
+		public override void AcceptVisitor(IAstVisitor visitor)
+		{
+			visitor.VisitDeclarationExpression(this);
+		}
+
+		public override T AcceptVisitor<T>(IAstVisitor<T> visitor)
+		{
+			return visitor.VisitDeclarationExpression(this);
+		}
+
+		public override S AcceptVisitor<T, S>(IAstVisitor<T, S> visitor, T data)
+		{
+			return visitor.VisitDeclarationExpression(this, data);
+		}
+
+		protected internal override bool DoMatch(AstNode other, Match match)
+		{
+			return other is DeclarationExpression o && Designation.DoMatch(o.Designation, match);
+		}
+	}
+}

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

@@ -42,10 +42,6 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			SetChildByRole(Roles.Identifier, Decompiler.CSharp.Syntax.Identifier.Create (identifier, location));
 		}
 		
-//		public Identifier IdentifierToken {
-//			get { return GetChildByRole (Roles.Identifier); }
-//		}
-		
 		public string Identifier {
 			get {
 				return GetChildByRole (Roles.Identifier).Name;

ICSharpCode.Decompiler/CSharp/Syntax/IAstVisitor.cs

@@ -35,6 +35,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 		void VisitCastExpression(CastExpression castExpression);
 		void VisitCheckedExpression(CheckedExpression checkedExpression);
 		void VisitConditionalExpression(ConditionalExpression conditionalExpression);
+		void VisitDeclarationExpression(DeclarationExpression declarationExpression);
 		void VisitDefaultValueExpression(DefaultValueExpression defaultValueExpression);
 		void VisitDirectionExpression(DirectionExpression directionExpression);
 		void VisitIdentifierExpression(IdentifierExpression identifierExpression);
@@ -153,7 +154,10 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 
 		void VisitInterpolation(Interpolation interpolation);
 		void VisitInterpolatedStringText(InterpolatedStringText interpolatedStringText);
-		
+
+		void VisitSingleVariableDesignation(SingleVariableDesignation singleVariableDesignation);
+		void VisitParenthesizedVariableDesignation(ParenthesizedVariableDesignation parenthesizedVariableDesignation);
+
 		void VisitNullNode(AstNode nullNode);
 		void VisitErrorNode(AstNode errorNode);
 		void VisitPatternPlaceholder(AstNode placeholder, PatternMatching.Pattern pattern);
@@ -175,6 +179,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 		S VisitCastExpression(CastExpression castExpression);
 		S VisitCheckedExpression(CheckedExpression checkedExpression);
 		S VisitConditionalExpression(ConditionalExpression conditionalExpression);
+		S VisitDeclarationExpression(DeclarationExpression declarationExpression);
 		S VisitDefaultValueExpression(DefaultValueExpression defaultValueExpression);
 		S VisitDirectionExpression(DirectionExpression directionExpression);
 		S VisitIdentifierExpression(IdentifierExpression identifierExpression);
@@ -294,6 +299,9 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 		S VisitInterpolation(Interpolation interpolation);
 		S VisitInterpolatedStringText(InterpolatedStringText interpolatedStringText);
 
+		S VisitSingleVariableDesignation(SingleVariableDesignation singleVariableDesignation);
+		S VisitParenthesizedVariableDesignation(ParenthesizedVariableDesignation parenthesizedVariableDesignation);
+
 		S VisitNullNode(AstNode nullNode);
 		S VisitErrorNode(AstNode errorNode);
 		S VisitPatternPlaceholder(AstNode placeholder, PatternMatching.Pattern pattern);
@@ -315,6 +323,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 		S VisitCastExpression(CastExpression castExpression, T data);
 		S VisitCheckedExpression(CheckedExpression checkedExpression, T data);
 		S VisitConditionalExpression(ConditionalExpression conditionalExpression, T data);
+		S VisitDeclarationExpression(DeclarationExpression declarationExpression, T data);
 		S VisitDefaultValueExpression(DefaultValueExpression defaultValueExpression, T data);
 		S VisitDirectionExpression(DirectionExpression directionExpression, T data);
 		S VisitIdentifierExpression(IdentifierExpression identifierExpression, T data);
@@ -434,6 +443,9 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 		S VisitInterpolation(Interpolation interpolation, T data);
 		S VisitInterpolatedStringText(InterpolatedStringText interpolatedStringText, T data);
 
+		S VisitSingleVariableDesignation(SingleVariableDesignation singleVariableDesignation, T data);
+		S VisitParenthesizedVariableDesignation(ParenthesizedVariableDesignation parenthesizedVariableDesignation, T data);
+
 		S VisitNullNode(AstNode nullNode, T data);
 		S VisitErrorNode(AstNode errorNode, T data);
 		S VisitPatternPlaceholder(AstNode placeholder, PatternMatching.Pattern pattern, T data);

ICSharpCode.Decompiler/CSharp/Syntax/VariableDesignation.cs

@@ -0,0 +1,112 @@
+// Copyright (c) 2020 Siegfried Pammer
+// 
+// Permission is hereby granted, free of charge, to any person obtaining a copy of this
+// software and associated documentation files (the "Software"), to deal in the Software
+// without restriction, including without limitation the rights to use, copy, modify, merge,
+// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
+// to whom the Software is furnished to do so, subject to the following conditions:
+// 
+// The above copyright notice and this permission notice shall be included in all copies or
+// substantial portions of the Software.
+// 
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
+// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+using System;
+using System.Collections.Generic;
+using System.Security.Cryptography.X509Certificates;
+using System.Text;
+
+using ICSharpCode.Decompiler.CSharp.Syntax.PatternMatching;
+using ICSharpCode.Decompiler.DebugInfo;
+
+namespace ICSharpCode.Decompiler.CSharp.Syntax
+{
+	public abstract class VariableDesignation : AstNode
+	{
+		public static Role<VariableDesignation> Role = new Role<VariableDesignation>("VariableDesignation");
+	}
+
+	/// <summary>
+	/// Identifier
+	/// </summary>
+	public class SingleVariableDesignation : VariableDesignation
+	{
+		public override NodeType NodeType => NodeType.Unknown;
+
+		public string Identifier {
+			get { return GetChildByRole(Roles.Identifier).Name; }
+			set { SetChildByRole(Roles.Identifier, Syntax.Identifier.Create(value)); }
+		}
+
+		public Identifier IdentifierToken {
+			get { return GetChildByRole(Roles.Identifier); }
+			set { SetChildByRole(Roles.Identifier, value); }
+		}
+
+		public override void AcceptVisitor(IAstVisitor visitor)
+		{
+			visitor.VisitSingleVariableDesignation(this);
+		}
+
+		public override T AcceptVisitor<T>(IAstVisitor<T> visitor)
+		{
+			return visitor.VisitSingleVariableDesignation(this);
+		}
+
+		public override S AcceptVisitor<T, S>(IAstVisitor<T, S> visitor, T data)
+		{
+			return visitor.VisitSingleVariableDesignation(this, data);
+		}
+
+		protected internal override bool DoMatch(AstNode other, Match match)
+		{
+			return other is SingleVariableDesignation o && MatchString(this.Identifier, o.Identifier);
+		}
+	}
+
+	/// <summary>
+	/// ( VariableDesignation (, VariableDesignation)* )
+	/// </summary>
+	public class ParenthesizedVariableDesignation : VariableDesignation
+	{
+
+		public CSharpTokenNode LParToken {
+			get { return GetChildByRole(Roles.LPar); }
+		}
+
+		public AstNodeCollection<VariableDesignation> VariableDesignations {
+			get { return GetChildrenByRole(VariableDesignation.Role); }
+		}
+
+		public CSharpTokenNode RParToken {
+			get { return GetChildByRole(Roles.RPar); }
+		}
+
+		public override NodeType NodeType => NodeType.Unknown;
+
+		public override void AcceptVisitor(IAstVisitor visitor)
+		{
+			visitor.VisitParenthesizedVariableDesignation(this);
+		}
+
+		public override T AcceptVisitor<T>(IAstVisitor<T> visitor)
+		{
+			return visitor.VisitParenthesizedVariableDesignation(this);
+		}
+
+		public override S AcceptVisitor<T, S>(IAstVisitor<T, S> visitor, T data)
+		{
+			return visitor.VisitParenthesizedVariableDesignation(this, data);
+		}
+
+		protected internal override bool DoMatch(AstNode other, Match match)
+		{
+			return other is ParenthesizedVariableDesignation o && VariableDesignations.DoMatch(o.VariableDesignations, match);
+		}
+	}
+}

ICSharpCode.Decompiler/ICSharpCode.Decompiler.csproj

@@ -70,7 +70,9 @@
     <Compile Include="CSharp\SequencePointBuilder.cs" />
     <Compile Include="CSharp\ProjectDecompiler\TargetFramework.cs" />
     <Compile Include="CSharp\ProjectDecompiler\TargetServices.cs" />
+    <Compile Include="CSharp\Syntax\DeclarationExpression.cs" />
     <Compile Include="CSharp\Syntax\FunctionPointerType.cs" />
+    <Compile Include="CSharp\Syntax\VariableDesignation.cs" />
     <Compile Include="IL\Transforms\FixLoneIsInst.cs" />
     <Compile Include="IL\Transforms\IndexRangeTransform.cs" />
     <Compile Include="CSharp\TranslatedStatement.cs" />