Applied some of the optimizations suggested by Kris Vandermotten. #150

ICSharpCode.Decompiler/Ast/TextOutputFormatter.cs

@@ -136,7 +136,7 @@ namespace ICSharpCode.Decompiler.Ast
 			if (ranges != null && ranges.Count > 0)
 			{
 				// find the ancestor that has method mapping as annotation
-				if (node.Ancestors != null && node.Ancestors.Count() > 0)
+				if (node.Parent != null)
 				{
 					var n = node.Ancestors.FirstOrDefault(a => a.Annotation<MemberMapping>() != null);
 					if (n != null) {

ICSharpCode.Decompiler/Ast/Transforms/DelegateConstruction.cs

@@ -61,7 +61,7 @@ namespace ICSharpCode.Decompiler.Ast.Transforms
 		
 		public override object VisitObjectCreateExpression(ObjectCreateExpression objectCreateExpression, object data)
 		{
-			if (objectCreateExpression.Arguments.Count() == 2) {
+			if (objectCreateExpression.Arguments.Count == 2) {
 				Expression obj = objectCreateExpression.Arguments.First();
 				Expression func = objectCreateExpression.Arguments.Last();
 				Annotation annotation = func.Annotation<Annotation>();

ICSharpCode.Decompiler/ILAst/GotoRemoval.cs

@@ -91,7 +91,7 @@ namespace ICSharpCode.Decompiler.ILAst
 					}
 				}
 				
-				var defaultCase = ilSwitch.CaseBlocks.Where(cb => cb.Values == null).SingleOrDefault();
+				var defaultCase = ilSwitch.CaseBlocks.SingleOrDefault(cb => cb.Values == null);
 				// If there is no default block, remove empty case blocks
 				if (defaultCase == null || (defaultCase.Body.Count == 1 && defaultCase.Body.Single().Match(ILCode.LoopOrSwitchBreak))) {
 					ilSwitch.CaseBlocks.RemoveAll(b => b.Body.Count == 1 && b.Body.Single().Match(ILCode.LoopOrSwitchBreak));
@@ -140,14 +140,14 @@ namespace ICSharpCode.Decompiler.ILAst
 				return true;
 			}
 			
-			ILNode breakBlock = GetParents(gotoExpr).Where(n => n is ILWhileLoop || n is ILSwitch).FirstOrDefault();
+			ILNode breakBlock = GetParents(gotoExpr).FirstOrDefault(n => n is ILWhileLoop || n is ILSwitch);
 			if (breakBlock != null && target == Exit(breakBlock, new HashSet<ILNode>() { gotoExpr })) {
 				gotoExpr.Code = ILCode.LoopOrSwitchBreak;
 				gotoExpr.Operand = null;
 				return true;
 			}
 			
-			ILNode continueBlock = GetParents(gotoExpr).Where(n => n is ILWhileLoop).FirstOrDefault();
+			ILNode continueBlock = GetParents(gotoExpr).FirstOrDefault(n => n is ILWhileLoop);
 			if (continueBlock != null && target == Enter(continueBlock, new HashSet<ILNode>() { gotoExpr })) {
 				gotoExpr.Code = ILCode.LoopContinue;
 				gotoExpr.Operand = null;
@@ -209,10 +209,10 @@ namespace ICSharpCode.Decompiler.ILAst
 				} else if (expr.Code == ILCode.Nop) {
 					return Exit(expr, visitedNodes);
 				} else if (expr.Code == ILCode.LoopOrSwitchBreak) {
-					ILNode breakBlock = GetParents(expr).Where(n => n is ILWhileLoop || n is ILSwitch).First();
+					ILNode breakBlock = GetParents(expr).First(n => n is ILWhileLoop || n is ILSwitch);
 					return Exit(breakBlock, new HashSet<ILNode>() { expr });
 				} else if (expr.Code == ILCode.LoopContinue) {
-					ILNode continueBlock = GetParents(expr).Where(n => n is ILWhileLoop).First();
+					ILNode continueBlock = GetParents(expr).First(n => n is ILWhileLoop);
 					return Enter(continueBlock, new HashSet<ILNode>() { expr });
 				} else {
 					return expr;

ICSharpCode.Decompiler/ILAst/ILAstBuilder.cs

@@ -455,7 +455,7 @@ namespace ICSharpCode.Decompiler.ILAst
 				if (byteCode.StoreTo != null && byteCode.StoreTo.Count > 1) {
 					var locVars = byteCode.StoreTo;
 					// For each of the variables, find the location where it is loaded - there should be preciesly one
-					var loadedBy = locVars.Select(locVar => reachableBody.SelectMany(bc => bc.StackBefore).Where(s => s.LoadFrom == locVar).Single()).ToList();
+					var loadedBy = locVars.Select(locVar => reachableBody.SelectMany(bc => bc.StackBefore).Single(s => s.LoadFrom == locVar)).ToList();
 					// We now know that all the variables have a single load,
 					// Let's make sure that they have also a single store - us
 					if (loadedBy.All(slot => slot.PushedBy.Length == 1 && slot.PushedBy[0] == byteCode)) {
@@ -572,7 +572,7 @@ namespace ICSharpCode.Decompiler.ILAst
 								    Loads  = new List<ByteCode>() { load }
 								});
 							} else if (storedBy.Length == 1) {
-								VariableInfo newVar = newVars.Where(v => v.Stores.Contains(storedBy[0])).Single();
+								VariableInfo newVar = newVars.Single(v => v.Stores.Contains(storedBy[0]));
 								newVar.Loads.Add(load);
 							} else {
 								List<VariableInfo> mergeVars = newVars.Where(v => v.Stores.Union(storedBy).Any()).ToList();

ICSharpCode.Decompiler/ILAst/ILAstOptimizer.cs

@@ -398,7 +398,7 @@ namespace ICSharpCode.Decompiler.ILAst
 					    lastNode.IsUnconditionalControlFlow())
 					{
 						// Try to reuse the label
-						ILLabel label = currNode is ILLabel ? ((ILLabel)currNode) : new ILLabel() { Name = "Block_" + (nextLabelIndex++) };
+						ILLabel label = currNode as ILLabel ?? new ILLabel() { Name = "Block_" + (nextLabelIndex++).ToString() };
 						
 						// Terminate the last block
 						if (!lastNode.IsUnconditionalControlFlow()) {

ICSharpCode.Decompiler/ILAst/LoopsAndConditions.cs

@@ -31,7 +31,7 @@ namespace ICSharpCode.Decompiler.ILAst
 	{
 		Dictionary<ILLabel, ControlFlowNode> labelToCfNode = new Dictionary<ILLabel, ControlFlowNode>();
 		
-		DecompilerContext context;
+		readonly DecompilerContext context;
 		
 		uint nextLabelIndex = 0;
 		
@@ -286,7 +286,7 @@ namespace ICSharpCode.Decompiler.ILAst
 								ILLabel condLabel = caseLabels[i];
 								
 								// Find or create new case block
-								ILSwitch.CaseBlock caseBlock = ilSwitch.CaseBlocks.Where(b => b.EntryGoto.Operand == condLabel).FirstOrDefault();
+								ILSwitch.CaseBlock caseBlock = ilSwitch.CaseBlocks.FirstOrDefault(b => b.EntryGoto.Operand == condLabel);
 								if (caseBlock == null) {
 									caseBlock = new ILSwitch.CaseBlock() {
 										Values = new List<int>(),

NRefactory/ICSharpCode.NRefactory/CSharp/Ast/ComposedType.cs

@@ -52,7 +52,7 @@ namespace ICSharpCode.NRefactory.CSharp
 		
 		public int PointerRank {
 			get {
-				return GetChildrenByRole(PointerRole).Count();
+				return GetChildrenByRole(PointerRole).Count;
 			}
 			set {
 				if (value < 0)
@@ -141,7 +141,7 @@ namespace ICSharpCode.NRefactory.CSharp
 		}
 		
 		public int Dimensions {
-			get { return 1 + GetChildrenByRole(Roles.Comma).Count(); }
+			get { return 1 + GetChildrenByRole(Roles.Comma).Count; }
 			set {
 				int d = this.Dimensions;
 				while (d > value) {

NRefactory/ICSharpCode.NRefactory/CSharp/Ast/Identifier.cs

@@ -96,7 +96,7 @@ namespace ICSharpCode.NRefactory.CSharp
 		{
 			if (name == null)
 				throw new ArgumentNullException("name");
-			IsVerbatim = name.StartsWith ("@");
+			IsVerbatim = name.Length > 0 && name[0] == '@';
 			this.Name = IsVerbatim ? name.Substring (1) : name;
 			this.startLocation = location;
 		}

NRefactory/ICSharpCode.NRefactory/CSharp/Parser/TypeSystemConvertVisitor.cs

@@ -263,7 +263,7 @@ namespace ICSharpCode.NRefactory.CSharp
 		#region Fields
 		public override IEntity VisitFieldDeclaration(FieldDeclaration fieldDeclaration, object data)
 		{
-			bool isSingleField = fieldDeclaration.Variables.Count() == 1;
+			bool isSingleField = fieldDeclaration.Variables.Count == 1;
 			Modifiers modifiers = fieldDeclaration.Modifiers;
 			DefaultField field = null;
 			foreach (VariableInitializer vi in fieldDeclaration.Variables) {
@@ -476,7 +476,7 @@ namespace ICSharpCode.NRefactory.CSharp
 		#region Events
 		public override IEntity VisitEventDeclaration(EventDeclaration eventDeclaration, object data)
 		{
-			bool isSingleEvent = eventDeclaration.Variables.Count() == 1;
+			bool isSingleEvent = eventDeclaration.Variables.Count == 1;
 			Modifiers modifiers = eventDeclaration.Modifiers;
 			DefaultEvent ev = null;
 			foreach (VariableInitializer vi in eventDeclaration.Variables) {

NRefactory/ICSharpCode.NRefactory/CSharp/Resolver/ResolveVisitor.cs

@@ -241,7 +241,7 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 		
 		ResolveResult VisitFieldOrEventDeclaration(AttributedNode fieldOrEventDeclaration)
 		{
-			int initializerCount = fieldOrEventDeclaration.GetChildrenByRole(FieldDeclaration.Roles.Variable).Count();
+			int initializerCount = fieldOrEventDeclaration.GetChildrenByRole(FieldDeclaration.Roles.Variable).Count;
 			ResolveResult result = null;
 			for (AstNode node = fieldOrEventDeclaration.FirstChild; node != null; node = node.NextSibling) {
 				if (node.Role == FieldDeclaration.Roles.Variable) {
@@ -939,7 +939,7 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 			                                        firstInitializer != null ? firstInitializer.Initializer : null,
 			                                        false);
 			
-			int initializerCount = variableDeclarationStatement.Variables.Count();
+			int initializerCount = variableDeclarationStatement.Variables.Count;
 			ResolveResult result = null;
 			for (AstNode node = variableDeclarationStatement.FirstChild; node != null; node = node.NextSibling) {
 				if (node.Role == FieldDeclaration.Roles.Variable) {