Fix "Missing variable name in created C# code". Closes #81.

ICSharpCode.Decompiler/Ast/AstBuilder.cs

@@ -599,7 +599,7 @@ namespace ICSharpCode.Decompiler.Ast
 					astMethod.Modifiers = ConvertModifiers(methodDef);
 				else
 					astMethod.PrivateImplementationType = ConvertType(methodDef.Overrides.First().DeclaringType);
-				astMethod.Body = AstMethodBodyBuilder.CreateMethodBody(methodDef, context);
+				astMethod.Body = AstMethodBodyBuilder.CreateMethodBody(methodDef, context, astMethod.Parameters);
 			}
 			ConvertAttributes(astMethod, methodDef);
 			if (methodDef.HasCustomAttributes && astMethod.Parameters.Count > 0) {
@@ -661,7 +661,7 @@ namespace ICSharpCode.Decompiler.Ast
 			}
 			astMethod.Name = CleanName(methodDef.DeclaringType.Name);
 			astMethod.Parameters.AddRange(MakeParameters(methodDef.Parameters));
-			astMethod.Body = AstMethodBodyBuilder.CreateMethodBody(methodDef, context);
+			astMethod.Body = AstMethodBodyBuilder.CreateMethodBody(methodDef, context, astMethod.Parameters);
 			ConvertAttributes(astMethod, methodDef);
 			return astMethod;
 		}
@@ -793,6 +793,7 @@ namespace ICSharpCode.Decompiler.Ast
 		{
 			foreach(ParameterDefinition paramDef in paramCol) {
 				ParameterDeclaration astParam = new ParameterDeclaration();
+				astParam.AddAnnotation(paramDef);
 				astParam.Type = ConvertType(paramDef.ParameterType, paramDef);
 				astParam.Name = paramDef.Name;
 				

ICSharpCode.Decompiler/Ast/AstMethodBodyBuilder.cs

@@ -24,7 +24,15 @@ namespace ICSharpCode.Decompiler.Ast
 		HashSet<ILVariable> localVariablesToDefine = new HashSet<ILVariable>(); // local variables that are missing a definition
 		HashSet<ILVariable> implicitlyDefinedVariables = new HashSet<ILVariable>(); // local variables that are implicitly defined (e.g. catch handler)
 		
-		public static BlockStatement CreateMethodBody(MethodDefinition methodDef, DecompilerContext context)
+		/// <summary>
+		/// Creates the body for the method definition.
+		/// </summary>
+		/// <param name="methodDef">Method definition to decompile.</param>
+		/// <param name="context">Decompilation context.</param>
+		/// <param name="parameters">Parameter declarations of the method being decompiled.
+		/// These are used to update the parameter names when the decompiler generates names for the parameters.</param>
+		/// <returns>Block for the method body</returns>
+		public static BlockStatement CreateMethodBody(MethodDefinition methodDef, DecompilerContext context, IEnumerable<ParameterDeclaration> parameters = null)
 		{
 			MethodDefinition oldCurrentMethod = context.CurrentMethod;
 			Debug.Assert(oldCurrentMethod == null || oldCurrentMethod == methodDef);
@@ -35,10 +43,10 @@ namespace ICSharpCode.Decompiler.Ast
 				builder.context = context;
 				builder.typeSystem = methodDef.Module.TypeSystem;
 				if (Debugger.IsAttached) {
-					return builder.CreateMethodBody();
+					return builder.CreateMethodBody(parameters);
 				} else {
 					try {
-						return builder.CreateMethodBody();
+						return builder.CreateMethodBody(parameters);
 					} catch (OperationCanceledException) {
 						throw;
 					} catch (Exception ex) {
@@ -50,7 +58,7 @@ namespace ICSharpCode.Decompiler.Ast
 			}
 		}
 		
-		public BlockStatement CreateMethodBody()
+		public BlockStatement CreateMethodBody(IEnumerable<ParameterDeclaration> parameters)
 		{
 			if (methodDef.Body == null) return null;
 			
@@ -69,6 +77,15 @@ namespace ICSharpCode.Decompiler.Ast
 			Debug.Assert(context.CurrentMethod == methodDef);
 			NameVariables.AssignNamesToVariables(context, astBuilder.Parameters, allVariables, ilMethod);
 			
+			if (parameters != null) {
+				foreach (var pair in (from p in parameters
+				                      join v in astBuilder.Parameters on p.Annotation<ParameterDefinition>() equals v.OriginalParameter
+				                      select new { p, v.Name }))
+				{
+					pair.p.Name = pair.Name;
+				}
+			}
+			
 			context.CancellationToken.ThrowIfCancellationRequested();
 			Ast.BlockStatement astBlock = TransformBlock(ilMethod);
 			CommentStatement.ReplaceAll(astBlock); // convert CommentStatements to Comments

ICSharpCode.Decompiler/Ast/NRefactoryExtensions.cs

@@ -17,7 +17,7 @@ namespace ICSharpCode.Decompiler.Ast
 		
 		public static T CopyAnnotationsFrom<T>(this T node, AstNode other) where T : AstNode
 		{
-			foreach (var annotation in other.Annotations<object>()) {
+			foreach (object annotation in other.Annotations) {
 				node.AddAnnotation(annotation);
 			}
 			return node;

ICSharpCode.Decompiler/Ast/Transforms/DelegateConstruction.cs

@@ -114,24 +114,36 @@ namespace ICSharpCode.Decompiler.Ast.Transforms
 			if (!IsAnonymousMethod(context, method))
 				return false;
 			
+			// Create AnonymousMethodExpression and prepare parameters
+			AnonymousMethodExpression ame = new AnonymousMethodExpression();
+			ame.Parameters.AddRange(AstBuilder.MakeParameters(method.Parameters));
+			ame.HasParameterList = true;
+			
 			// Decompile the anonymous method:
 			
 			DecompilerContext subContext = context.Clone();
 			subContext.CurrentMethod = method;
-			BlockStatement body = AstMethodBodyBuilder.CreateMethodBody(method, subContext);
+			BlockStatement body = AstMethodBodyBuilder.CreateMethodBody(method, subContext, ame.Parameters);
 			TransformationPipeline.RunTransformationsUntil(body, v => v is DelegateConstruction, subContext);
 			body.AcceptVisitor(this, null);
 			
-			AnonymousMethodExpression ame = new AnonymousMethodExpression();
+			
 			bool isLambda = false;
-			if (method.Parameters.All(p => string.IsNullOrEmpty(p.Name))) {
-				ame.HasParameterList = false;
-			} else {
-				ame.HasParameterList = true;
-				ame.Parameters.AddRange(AstBuilder.MakeParameters(method.Parameters));
 			if (ame.Parameters.All(p => p.ParameterModifier == ParameterModifier.None)) {
 				isLambda = (body.Statements.Count == 1 && body.Statements.Single() is ReturnStatement);
 			}
+			// Remove the parameter list from an AnonymousMethodExpression if the original method had no names,
+			// and the parameters are not used in the method body
+			if (!isLambda && method.Parameters.All(p => string.IsNullOrEmpty(p.Name))) {
+				var parameterReferencingIdentifiers =
+					from ident in body.Descendants.OfType<IdentifierExpression>()
+					let v = ident.Annotation<ILVariable>()
+					where v != null && v.IsParameter && method.Parameters.Contains(v.OriginalParameter)
+					select ident;
+				if (!parameterReferencingIdentifiers.Any()) {
+					ame.Parameters.Clear();
+					ame.HasParameterList = false;
+				}
 			}
 			
 			// Replace all occurrences of 'this' in the method body with the delegate's target: