From 7c3fd3afda0b09a24df53efa5f378533b0ef3d73 Mon Sep 17 00:00:00 2001
From: Pent Ploompuu <kaalikas@gmail.com>
Date: Thu, 11 Aug 2011 22:14:42 +0300
Subject: [PATCH] Use annotations to mark lifted operators that can't be
 transformed by PushNegation

---
 ICSharpCode.Decompiler/Ast/Annotations.cs     |  7 ------
 .../Ast/AstMethodBodyBuilder.cs               |  2 +-
 .../Ast/Transforms/PushNegation.cs            | 25 +++++++++++--------
 3 files changed, 15 insertions(+), 19 deletions(-)

diff --git a/ICSharpCode.Decompiler/Ast/Annotations.cs b/ICSharpCode.Decompiler/Ast/Annotations.cs
index 6673b2ce4..257f889c0 100644
--- a/ICSharpCode.Decompiler/Ast/Annotations.cs
+++ b/ICSharpCode.Decompiler/Ast/Annotations.cs
@@ -12,11 +12,4 @@ namespace ICSharpCode.Decompiler.Ast
 			this.InferredType = inferredType;
 		}
 	}
-
-	sealed class InvisibleParenthesis
-	{
-		InvisibleParenthesis() { }
-
-		public static readonly InvisibleParenthesis Value = new InvisibleParenthesis();
-	}
 }
diff --git a/ICSharpCode.Decompiler/Ast/AstMethodBodyBuilder.cs b/ICSharpCode.Decompiler/Ast/AstMethodBodyBuilder.cs
index 0c9bce8e6..3852aec80 100644
--- a/ICSharpCode.Decompiler/Ast/AstMethodBodyBuilder.cs
+++ b/ICSharpCode.Decompiler/Ast/AstMethodBodyBuilder.cs
@@ -815,7 +815,7 @@ namespace ICSharpCode.Decompiler.Ast
 				case ILCode.InitializedObject:
 					return new InitializedObjectExpression();
 				case ILCode.Wrap:
-					return new ParenthesizedExpression(arg1).WithAnnotation(InvisibleParenthesis.Value);
+					return arg1.WithAnnotation(PushNegation.LiftedOperatorAnnotation);
 				case ILCode.AddressOf:
 					return MakeRef(arg1);
 				case ILCode.NullableOf:
diff --git a/ICSharpCode.Decompiler/Ast/Transforms/PushNegation.cs b/ICSharpCode.Decompiler/Ast/Transforms/PushNegation.cs
index e0c54f1a2..193c5e692 100644
--- a/ICSharpCode.Decompiler/Ast/Transforms/PushNegation.cs
+++ b/ICSharpCode.Decompiler/Ast/Transforms/PushNegation.cs
@@ -26,8 +26,18 @@ namespace ICSharpCode.Decompiler.Ast.Transforms
 {
 	public class PushNegation: DepthFirstAstVisitor<object, object>, IAstTransform
 	{
+		sealed class LiftedOperator { }
+		/// <summary>
+		/// Annotation for lifted operators that cannot be transformed by PushNegation
+		/// </summary>
+		public static readonly object LiftedOperatorAnnotation = new LiftedOperator();
+
 		public override object VisitUnaryOperatorExpression(UnaryOperatorExpression unary, object data)
 		{
+			// lifted operators can't be transformed
+			if (unary.Annotation<LiftedOperator>() != null || unary.Expression.Annotation<LiftedOperator>() != null)
+				return base.VisitUnaryOperatorExpression(unary, data);
+
 			// Remove double negation
 			// !!a
 			if (unary.Operator == UnaryOperatorType.Not &&
@@ -108,6 +118,10 @@ namespace ICSharpCode.Decompiler.Ast.Transforms
 		
 		public override object VisitBinaryOperatorExpression(BinaryOperatorExpression binaryOperatorExpression, object data)
 		{
+			// lifted operators can't be transformed
+			if (binaryOperatorExpression.Annotation<LiftedOperator>() != null)
+				return base.VisitBinaryOperatorExpression(binaryOperatorExpression, data);
+
 			BinaryOperatorType op = binaryOperatorExpression.Operator;
 			bool? rightOperand = null;
 			if (binaryOperatorExpression.Right is PrimitiveExpression)
@@ -146,16 +160,5 @@ namespace ICSharpCode.Decompiler.Ast.Transforms
 		{
 			node.AcceptVisitor(this, null);
 		}
-
-		public override object VisitParenthesizedExpression(ParenthesizedExpression expr, object data)
-		{
-			// extra parentheses are redundant after this transformation
-			if(expr.Annotation<InvisibleParenthesis>() != null) {
-				var res = expr.Expression;
-				expr.ReplaceWith(res);
-				return res.AcceptVisitor(this, data);
-			}
-			return base.VisitParenthesizedExpression(expr, data);
-		}
 	}
 }