fix #524 - Mistake ILSpy decompile: delegate instantiation is only removed if an implicit conversion exists.

ICSharpCode.Decompiler/Ast/Annotations.cs

@@ -10,10 +10,12 @@ namespace ICSharpCode.Decompiler.Ast
 	public class TypeInformation
 	{
 		public readonly TypeReference InferredType;
+		public readonly TypeReference ExpectedType;
 		
-		public TypeInformation(TypeReference inferredType)
+		public TypeInformation(TypeReference inferredType, TypeReference expectedType)
 		{
 			this.InferredType = inferredType;
+			this.ExpectedType = expectedType;
 		}
 	}
 	

ICSharpCode.Decompiler/Ast/AstMethodBodyBuilder.cs

@@ -262,7 +262,7 @@ namespace ICSharpCode.Decompiler.Ast
 				result = node;
 			
 			if (result != null)
-				result = result.WithAnnotation(new TypeInformation(expr.InferredType));
+				result = result.WithAnnotation(new TypeInformation(expr.InferredType, expr.ExpectedType));
 			
 			if (result != null)
 				return result.WithAnnotation(ilRanges);

ICSharpCode.Decompiler/Ast/Transforms/DelegateConstruction.cs

@@ -180,8 +180,8 @@ namespace ICSharpCode.Decompiler.Ast.Transforms
 			foreach (AstNode node in body.Descendants) {
 				if (node is ThisReferenceExpression)
 					node.ReplaceWith(target.Clone());
-				
 			}
+			Expression replacement;
 			if (isLambda) {
 				LambdaExpression lambda = new LambdaExpression();
 				lambda.CopyAnnotationsFrom(ame);
@@ -189,13 +189,32 @@ namespace ICSharpCode.Decompiler.Ast.Transforms
 				Expression returnExpr = ((ReturnStatement)body.Statements.Single()).Expression;
 				returnExpr.Remove();
 				lambda.Body = returnExpr;
-				objectCreateExpression.ReplaceWith(lambda);
+				replacement = lambda;
 			} else {
 				ame.Body = body;
-				objectCreateExpression.ReplaceWith(ame);
+				replacement = ame;
+			}
+			var expectedType = objectCreateExpression.Annotation<TypeInformation>().ExpectedType.Resolve();
+			if (expectedType != null && !IsDelegate(expectedType)) {
+				var simplifiedDelegateCreation = (ObjectCreateExpression)objectCreateExpression.Clone();
+				simplifiedDelegateCreation.Arguments.Clear();
+				simplifiedDelegateCreation.Arguments.Add(replacement);
+				replacement = simplifiedDelegateCreation;
 			}
+			objectCreateExpression.ReplaceWith(replacement);
 			return true;
 		}
+
+		static bool IsDelegate(TypeDefinition type)
+		{
+			if (type.BaseType != null && type.BaseType.Namespace == "System") {
+				if (type.BaseType.Name == "MulticastDelegate")
+					return true;
+				if (type.BaseType.Name == "Delegate" && type.Name != "MulticastDelegate")
+					return true;
+			}
+			return false;
+		}
 		
 		internal static bool IsPotentialClosure(DecompilerContext context, TypeDefinition potentialDisplayClass)
 		{