[CodeIssues] Add helper FindReferences(AstNode, IVariable) to BaseRefactoringContext.

ICSharpCode.NRefactory.CSharp/ICSharpCode.NRefactory.CSharp.csproj

@@ -324,7 +324,6 @@
     <Compile Include="Refactoring\CodeIssues\VariableNotUsedIssues\LocalVariableNotUsedIssue.cs" />
     <Compile Include="Refactoring\CodeIssues\VariableNotUsedIssues\ParameterNotUsedIssue.cs" />
     <Compile Include="Refactoring\CodeIssues\TypeParameterNotUsedIssue.cs" />
-    <Compile Include="Refactoring\CodeIssues\VariableNotUsedIssues\VariableNotUsedIssue.cs" />
     <Compile Include="Refactoring\CodeIssues\VariableOnlyAssignedIssues\ParameterOnlyAssignedIssue.cs" />
     <Compile Include="Refactoring\CodeIssues\VariableOnlyAssignedIssues\VariableOnlyAssignedIssue.cs" />
     <Compile Include="Refactoring\DocumentScript.cs" />

ICSharpCode.NRefactory.CSharp/Refactoring/BaseRefactoringContext.cs

@@ -36,6 +36,7 @@ using ICSharpCode.NRefactory.Editor;
 using System.ComponentModel.Design;
 using ICSharpCode.NRefactory.CSharp.Analysis;
 using ICSharpCode.NRefactory.Utils;
+using System.Collections.Generic;
 
 namespace ICSharpCode.NRefactory.CSharp.Refactoring
 {
@@ -87,6 +88,7 @@ namespace ICSharpCode.NRefactory.CSharp.Refactoring
 		{
 			this.resolver = resolver;
 			this.cancellationToken = cancellationToken;
+			this.referenceFinder = new LocalReferenceFinder(resolver);
 		}
 
 
@@ -161,6 +163,14 @@ namespace ICSharpCode.NRefactory.CSharp.Refactoring
 		{
 			return new CompositeFormatStringParser().Parse(source);
 		}
+
+		LocalReferenceFinder referenceFinder;
+
+		public IList<ReferenceResult> FindReferences(AstNode rootNode, IVariable variable)
+		{
+			return referenceFinder.FindReferences(rootNode, variable);
+		}
+
 		#endregion
 
 		/// <summary>

ICSharpCode.NRefactory.CSharp/Refactoring/CodeIssues/AccessToClosureIssues/AccessToClosureIssue.cs

@@ -27,7 +27,6 @@
 using System.Collections.Generic;
 using System.Linq;
 using ICSharpCode.NRefactory.CSharp.Analysis;
-using ICSharpCode.NRefactory.CSharp.Resolver;
 using ICSharpCode.NRefactory.Semantics;
 using ICSharpCode.NRefactory.TypeSystem;
 
@@ -82,7 +81,6 @@ namespace ICSharpCode.NRefactory.CSharp.Refactoring
 				: base (context)
 			{
 				this.title = context.TranslateString (issueProvider.Title);
-				this.referenceFinder = new LocalReferenceFinder(context);
 				this.issueProvider = issueProvider;
 			}
 
@@ -122,24 +120,18 @@ namespace ICSharpCode.NRefactory.CSharp.Refactoring
 				base.VisitParameterDeclaration (parameterDeclaration);
 			}
 
-			LocalReferenceFinder referenceFinder;
-
-			void FindLocalReferences (AstNode rootNode, IVariable variable, FoundReferenceCallback callback)
+			void CheckVariable(IVariable variable, Statement env)
 			{
-				referenceFinder.FindReferences(rootNode, variable, callback);
-			}
-
-			void CheckVariable (IVariable variable, Statement env)
-			{
-				if (!issueProvider.IsTargetVariable (variable))
+				if (!issueProvider.IsTargetVariable(variable))
 					return;
 
 				var root = new Environment (env, env);
 				var envLookup = new Dictionary<AstNode, Environment> ();
 				envLookup [env] = root;
 
-				FindLocalReferences (env, variable, (astNode, resolveResult) => 
-					AddNode (envLookup, new Node (astNode, issueProvider.GetNodeKind (astNode))));
+				foreach (var result in ctx.FindReferences(env, variable)) {
+					AddNode(envLookup, new Node(result.Node, issueProvider.GetNodeKind(result.Node)));
+				}
 
 				root.SortChildren ();
 				CollectIssues (root, variable.Name);

ICSharpCode.NRefactory.CSharp/Refactoring/CodeIssues/ForControlVariableNotModifiedIssue.cs

@@ -45,12 +45,9 @@ namespace ICSharpCode.NRefactory.CSharp.Refactoring
 
 		class GatherVisitor : GatherVisitorBase
 		{
-			LocalReferenceFinder referenceFinder;
-			
 			public GatherVisitor (BaseRefactoringContext ctx)
 				: base (ctx)
 			{
-				this.referenceFinder = new LocalReferenceFinder(ctx);
 			}
 
 			static VariableInitializer GetControlVariable(VariableDeclarationStatement variableDecl, 
@@ -105,25 +102,24 @@ namespace ICSharpCode.NRefactory.CSharp.Refactoring
 				if (localResolveResult == null)
 					return;
 
+				var results = ctx.FindReferences (forStatement, localResolveResult.Variable);
 				var modified = false;
-				referenceFinder.FindReferences (forStatement, localResolveResult.Variable,
-					(node, resolveResult) =>
-					{
-						if (modified)
-							return;
-
-						var unary = node.Parent as UnaryOperatorExpression;
-						if (unary != null && unary.Expression == node) {
-							modified = unary.Operator == UnaryOperatorType.Decrement ||
-								unary.Operator == UnaryOperatorType.PostDecrement ||
-								unary.Operator == UnaryOperatorType.Increment ||
-								unary.Operator == UnaryOperatorType.PostIncrement;
-							return;
-						}
+				foreach (var result in results) {
+					if (modified)
+						break;
+					var node = result.Node;
+					var unary = node.Parent as UnaryOperatorExpression;
+					if (unary != null && unary.Expression == node) {
+						modified = unary.Operator == UnaryOperatorType.Decrement ||
+							unary.Operator == UnaryOperatorType.PostDecrement ||
+							unary.Operator == UnaryOperatorType.Increment ||
+							unary.Operator == UnaryOperatorType.PostIncrement;
+						continue;
+					}
 
-						var assignment = node.Parent as AssignmentExpression;
-						modified = assignment != null && assignment.Left == node;
-					});
+					var assignment = node.Parent as AssignmentExpression;
+					modified = assignment != null && assignment.Left == node;
+				}
 
 				if (!modified)
 					AddIssue (controlVariable.NameToken,

ICSharpCode.NRefactory.CSharp/Refactoring/CodeIssues/RedundantAssignmentIssue.cs

@@ -26,7 +26,6 @@
 
 using System.Collections.Generic;
 using System.Linq;
-using ICSharpCode.NRefactory.CSharp.Resolver;
 using ICSharpCode.NRefactory.Semantics;
 
 namespace ICSharpCode.NRefactory.CSharp.Refactoring
@@ -48,12 +47,9 @@ namespace ICSharpCode.NRefactory.CSharp.Refactoring
 
 		class GatherVisitor : GatherVisitorBase
 		{
-			LocalReferenceFinder referenceFinder;
-
 			public GatherVisitor (BaseRefactoringContext ctx, SyntaxTree unit)
 				: base (ctx)
 			{
-				referenceFinder = new LocalReferenceFinder(ctx);
 			}
 
 			public override void VisitParameterDeclaration (ParameterDeclaration parameterDeclaration)
@@ -91,30 +87,35 @@ namespace ICSharpCode.NRefactory.CSharp.Refactoring
 				var references = new HashSet<AstNode> ();
 				var refStatements = new HashSet<Statement> ();
 				var usedInLambda = false;
-				referenceFinder.FindReferences (rootStatement, resolveResult.Variable, (astNode, rr) => {
-						if (usedInLambda || astNode == variableDecl)
-							return;
-
-						var parent = astNode.Parent;
-						while (!(parent == null || parent is Statement || parent is LambdaExpression))
-							parent = parent.Parent;
-						if (parent == null)
-							return;
-
-						var statement = parent as Statement;
-						if (statement != null) {
-							references.Add (astNode);
-							refStatements.Add (statement);
-						}
+				var results = ctx.FindReferences (rootStatement, resolveResult.Variable);
+				foreach (var result in results) {
+					var node = result.Node;
+					if (node == variableDecl)
+						continue;
+
+					var parent = node.Parent;
+					while (!(parent == null || parent is Statement || parent is LambdaExpression))
+						parent = parent.Parent;
+					if (parent == null)
+						continue;
+
+					var statement = parent as Statement;
+					if (statement != null) {
+						references.Add (node);
+						refStatements.Add (statement);
+					}
 
-						while (parent != null && parent != rootStatement) {
-							if (parent is LambdaExpression || parent is AnonymousMethodExpression) {
-								usedInLambda = true;
-								break;
-							}
-							parent = parent.Parent;
+					while (parent != null && parent != rootStatement) {
+						if (parent is LambdaExpression || parent is AnonymousMethodExpression) {
+							usedInLambda = true;
+							break;
 						}
-					});
+						parent = parent.Parent;
+					}
+					if (usedInLambda) {
+						break;
+					}
+				}
 
 				// stop analyzing if the variable is used in any lambda expression or anonymous method
 				if (usedInLambda)

ICSharpCode.NRefactory.CSharp/Refactoring/CodeIssues/VariableNotUsedIssues/LocalVariableNotUsedIssue.cs

@@ -25,6 +25,8 @@
 // THE SOFTWARE.
 
 using ICSharpCode.NRefactory.Semantics;
+using System.Linq;
+using ICSharpCode.NRefactory.TypeSystem;
 
 namespace ICSharpCode.NRefactory.CSharp.Refactoring
 {
@@ -33,24 +35,22 @@ namespace ICSharpCode.NRefactory.CSharp.Refactoring
 					   Category = IssueCategories.Redundancies,
 					   Severity = Severity.Warning,
 					   IssueMarker = IssueMarker.GrayOut)]
-	public class LocalVariableNotUsedIssue : VariableNotUsedIssue
+	public class LocalVariableNotUsedIssue : ICodeIssueProvider
 	{
-		internal override GatherVisitorBase GetGatherVisitor (BaseRefactoringContext context)
+		#region ICodeIssueProvider implementation
+
+		public System.Collections.Generic.IEnumerable<CodeIssue> GetIssues(BaseRefactoringContext context)
 		{
-			return new GatherVisitor (context, this);
+			return new GatherVisitor (context).GetIssues ();
 		}
 
+		#endregion
+		
 		class GatherVisitor : GatherVisitorBase
 		{
-			LocalReferenceFinder referenceFinder;
-
-			VariableNotUsedIssue inspector;
-
-			public GatherVisitor (BaseRefactoringContext ctx, VariableNotUsedIssue inspector)
+			public GatherVisitor (BaseRefactoringContext ctx)
 				: base (ctx)
 			{
-				this.inspector = inspector;
-				this.referenceFinder = new LocalReferenceFinder(ctx);
 			}
 
 			public override void VisitVariableInitializer (VariableInitializer variableInitializer)
@@ -68,8 +68,7 @@ namespace ICSharpCode.NRefactory.CSharp.Refactoring
 				if (resolveResult == null)
 					return;
 
-				var b = inspector.FindUsage(referenceFinder, decl.Parent, resolveResult.Variable, variableInitializer);
-				if (b)
+				if (IsUsed (decl.Parent, resolveResult.Variable, variableInitializer))
 					return;
 
 				AddIssue (variableInitializer.NameToken, ctx.TranslateString ("Remove unused local variable"),
@@ -94,11 +93,16 @@ namespace ICSharpCode.NRefactory.CSharp.Refactoring
 				if (resolveResult == null)
 					return;
 
-				if (inspector.FindUsage (referenceFinder, foreachStatement, resolveResult.Variable, foreachStatement.VariableNameToken))
+				if (IsUsed (foreachStatement, resolveResult.Variable, foreachStatement.VariableNameToken))
 					return;
 
 				AddIssue (foreachStatement.VariableNameToken, ctx.TranslateString ("Local variable is never used"));
 			}
+
+			bool IsUsed(AstNode rootNode, IVariable variable, AstNode variableNode)
+			{
+				return ctx.FindReferences(rootNode, variable).Any(result => result.Node != variableNode);
+			}
 		}
 
 	}

ICSharpCode.NRefactory.CSharp/Refactoring/CodeIssues/VariableNotUsedIssues/ParameterNotUsedIssue.cs

@@ -27,6 +27,7 @@
 using ICSharpCode.NRefactory.Semantics;
 using System.Linq;
 using ICSharpCode.NRefactory.TypeSystem;
+using System.Collections.Generic;
 
 namespace ICSharpCode.NRefactory.CSharp.Refactoring
 {
@@ -35,25 +36,20 @@ namespace ICSharpCode.NRefactory.CSharp.Refactoring
 					   Category = IssueCategories.Redundancies,
 					   Severity = Severity.Warning,
 					   IssueMarker = IssueMarker.GrayOut)]
-	public class ParameterNotUsedIssue : VariableNotUsedIssue
+	public class ParameterNotUsedIssue : ICodeIssueProvider
 	{
-
-		internal override GatherVisitorBase GetGatherVisitor (BaseRefactoringContext context)
+		#region ICodeIssueProvider implementation
+		public IEnumerable<CodeIssue> GetIssues(BaseRefactoringContext context)
 		{
-			return new GatherVisitor (context, this);
+			return new GatherVisitor (context).GetIssues ();
 		}
+		#endregion
 
 		class GatherVisitor : GatherVisitorBase
 		{
-			VariableNotUsedIssue inspector;
-
-			LocalReferenceFinder referenceFinder;
-
-			public GatherVisitor (BaseRefactoringContext ctx, VariableNotUsedIssue inspector)
+			public GatherVisitor (BaseRefactoringContext ctx)
 				: base (ctx)
 			{
-				this.inspector = inspector;
-				this.referenceFinder = new LocalReferenceFinder(ctx);
 			}
 
 			public override void VisitMethodDeclaration(MethodDeclaration methodDeclaration)
@@ -85,7 +81,7 @@ namespace ICSharpCode.NRefactory.CSharp.Refactoring
 				if (resolveResult == null)
 					return;
 
-				if (inspector.FindUsage (referenceFinder, parameterDeclaration.Parent, resolveResult.Variable, parameterDeclaration))
+				if (ctx.FindReferences (parameterDeclaration.Parent, resolveResult.Variable).Any(r => r.Node != parameterDeclaration))
 					return;
 
 				AddIssue (parameterDeclaration.NameToken, ctx.TranslateString ("Parameter is never used"));

ICSharpCode.NRefactory.CSharp/Refactoring/CodeIssues/VariableNotUsedIssues/VariableNotUsedIssue.cs

@@ -1,54 +0,0 @@
-// 
-// VariableNotUsedIssue.cs
-// 
-// Author:
-//      Mansheng Yang <lightyang0@gmail.com>
-// 
-// Copyright (c) 2012 Mansheng Yang <lightyang0@gmail.com>
-// 
-// 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.Collections.Generic;
-using System.Linq;
-using ICSharpCode.NRefactory.TypeSystem;
-
-namespace ICSharpCode.NRefactory.CSharp.Refactoring
-{
-	public abstract class VariableNotUsedIssue : ICodeIssueProvider
-	{
-		public IEnumerable<CodeIssue> GetIssues (BaseRefactoringContext context)
-		{
-			var unit = context.RootNode as SyntaxTree;
-			if (unit == null)
-				return Enumerable.Empty<CodeIssue> ();
-			return GetGatherVisitor(context).GetIssues ();
-		}
-
-		public bool FindUsage (LocalReferenceFinder referenceFinder, AstNode rootNode, IVariable variable, AstNode declaration)
-		{
-			var found = false;
-			referenceFinder.FindReferences (rootNode, variable,	(node, resolveResult) => {
-				found |= node != declaration;
-			});
-			return found;
-		}
-
-		internal abstract GatherVisitorBase GetGatherVisitor (BaseRefactoringContext context);
-	}
-}

ICSharpCode.NRefactory.CSharp/Refactoring/CodeIssues/VariableOnlyAssignedIssues/LocalVariableOnlyAssignedIssue.cs

@@ -43,11 +43,9 @@ namespace ICSharpCode.NRefactory.CSharp.Refactoring
 
 		class GatherVisitor : GatherVisitorBase
 		{
-			LocalReferenceFinder referenceFinder;
 			public GatherVisitor (BaseRefactoringContext ctx)
 				: base (ctx)
 			{
-				referenceFinder = new LocalReferenceFinder(ctx);
 			}
 
 			public override void VisitVariableInitializer (VariableInitializer variableInitializer)
@@ -61,7 +59,7 @@ namespace ICSharpCode.NRefactory.CSharp.Refactoring
 				var resolveResult = ctx.Resolve (variableInitializer) as LocalResolveResult;
 				if (resolveResult == null)
 					return;
-				if (!TestOnlyAssigned (referenceFinder, decl.Parent, resolveResult.Variable))
+				if (!TestOnlyAssigned (ctx, decl.Parent, resolveResult.Variable))
 					return;
 				AddIssue (variableInitializer.NameToken,
 					ctx.TranslateString ("Local variable is assigned by its value is never used"));

ICSharpCode.NRefactory.CSharp/Refactoring/CodeIssues/VariableOnlyAssignedIssues/ParameterOnlyAssignedIssue.cs

@@ -23,7 +23,6 @@
 // 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.NRefactory.Semantics;
 
 namespace ICSharpCode.NRefactory.CSharp.Refactoring
@@ -35,32 +34,33 @@ namespace ICSharpCode.NRefactory.CSharp.Refactoring
 					   IssueMarker = IssueMarker.Underline)]
 	public class ParameterOnlyAssignedIssue : VariableOnlyAssignedIssue
 	{
-		internal override GatherVisitorBase GetGatherVisitor (BaseRefactoringContext ctx)
+		internal override GatherVisitorBase GetGatherVisitor(BaseRefactoringContext ctx)
 		{
-			return new GatherVisitor (ctx);
+			return new GatherVisitor(ctx);
 		}
 
 		private class GatherVisitor : GatherVisitorBase
 		{
-			LocalReferenceFinder referenceFinder;
-			public GatherVisitor (BaseRefactoringContext ctx)
+			public GatherVisitor(BaseRefactoringContext ctx)
 				: base (ctx)
 			{
-				referenceFinder = new LocalReferenceFinder(ctx);
 			}
 
-			public override void VisitParameterDeclaration (ParameterDeclaration parameterDeclaration)
+			public override void VisitParameterDeclaration(ParameterDeclaration parameterDeclaration)
 			{
-				base.VisitParameterDeclaration (parameterDeclaration);
+				base.VisitParameterDeclaration(parameterDeclaration);
 
-				var resolveResult = ctx.Resolve (parameterDeclaration) as LocalResolveResult;
+				var resolveResult = ctx.Resolve(parameterDeclaration) as LocalResolveResult;
 				if (resolveResult == null)
 					return;
-				if (parameterDeclaration.ParameterModifier == ParameterModifier.Out || parameterDeclaration.ParameterModifier == ParameterModifier.Ref
-				    || !TestOnlyAssigned (referenceFinder, parameterDeclaration.Parent, resolveResult.Variable))
+
+				var parameterModifier = parameterDeclaration.ParameterModifier;
+				if (parameterModifier == ParameterModifier.Out || parameterModifier == ParameterModifier.Ref ||
+					!TestOnlyAssigned(ctx, parameterDeclaration.Parent, resolveResult.Variable)) {
 					return;
-				AddIssue (parameterDeclaration.NameToken, 
-					ctx.TranslateString ("Parameter is assigned by its value is never used"));
+				}
+				AddIssue(parameterDeclaration.NameToken, 
+					ctx.TranslateString("Parameter is assigned by its value is never used"));
 			}
 		}
 	}

ICSharpCode.NRefactory.CSharp/Refactoring/CodeIssues/VariableOnlyAssignedIssues/VariableOnlyAssignedIssue.cs

@@ -36,46 +36,47 @@ namespace ICSharpCode.NRefactory.CSharp.Refactoring
 			return GetGatherVisitor (context).GetIssues ();
 		}
 
-		protected static bool TestOnlyAssigned (LocalReferenceFinder referenceFinder, AstNode rootNode, IVariable variable)
+		protected static bool TestOnlyAssigned(BaseRefactoringContext ctx, AstNode rootNode, IVariable variable)
 		{
 			var assignment = false;
 			var nonAssignment = false;
-			referenceFinder.FindReferences (rootNode, variable, (node, resolveResult) => {
-					if (node is ParameterDeclaration)
-						return;
+			foreach (var result in ctx.FindReferences(rootNode, variable)) {
+				var node = result.Node;
+				if (node is ParameterDeclaration)
+					continue;
 
-					if (node is VariableInitializer) {
-						if (!(node as VariableInitializer).Initializer.IsNull)
-							assignment = true;
-						return;
-					}
+				if (node is VariableInitializer) {
+					if (!(node as VariableInitializer).Initializer.IsNull)
+						assignment = true;
+					continue;
+				}
 
-					if (node is IdentifierExpression) {
-						var parent = node.Parent;
-						if (parent is AssignmentExpression) {
-							if (((AssignmentExpression)parent).Left == node) {
-								assignment = true;
-								return;
-							}
-						} else if (parent is UnaryOperatorExpression) {
-							var op = ((UnaryOperatorExpression)parent).Operator;
-							switch (op) {
+				if (node is IdentifierExpression) {
+					var parent = node.Parent;
+					if (parent is AssignmentExpression) {
+						if (((AssignmentExpression)parent).Left == node) {
+							assignment = true;
+							continue;
+						}
+					} else if (parent is UnaryOperatorExpression) {
+						var op = ((UnaryOperatorExpression)parent).Operator;
+						switch (op) {
 							case UnaryOperatorType.Increment:
 							case UnaryOperatorType.PostIncrement:
 							case UnaryOperatorType.Decrement:
 							case UnaryOperatorType.PostDecrement:
 								assignment = true;
-								return;
-							}
-						} else if (parent is DirectionExpression) {
-							if (((DirectionExpression)parent).FieldDirection == FieldDirection.Out) {
-								assignment = true;
-								return;
-							}
+								continue;
+						}
+					} else if (parent is DirectionExpression) {
+						if (((DirectionExpression)parent).FieldDirection == FieldDirection.Out) {
+							assignment = true;
+							continue;
 						}
 					}
-					nonAssignment = true;
-				});
+				}
+				nonAssignment = true;
+			}
 			return assignment && !nonAssignment;
 		}
 

ICSharpCode.NRefactory.CSharp/Refactoring/LocalReferenceFinder.cs

@@ -29,7 +29,6 @@ using System.Linq;
 using ICSharpCode.NRefactory.CSharp.Resolver;
 using ICSharpCode.NRefactory.Semantics;
 using ICSharpCode.NRefactory.TypeSystem;
-using System;
 using ICSharpCode.NRefactory.Utils;
 using System.Diagnostics;
 
@@ -48,7 +47,9 @@ namespace ICSharpCode.NRefactory.CSharp.Refactoring
 	{
 		LocalReferenceLocator locator;
 
-		MultiDictionary<IVariable, Tuple<AstNode, LocalResolveResult>> references = new MultiDictionary<IVariable, Tuple<AstNode, LocalResolveResult>>();
+		MultiDictionary<IVariable, ReferenceResult> references = new MultiDictionary<IVariable, ReferenceResult>();
+		
+		HashSet<AstNode> visitedRoots = new HashSet<AstNode>();
 		
 		public LocalReferenceFinder(CSharpAstResolver resolver)
 		{
@@ -59,8 +60,6 @@ namespace ICSharpCode.NRefactory.CSharp.Refactoring
 		{
 		}
 
-		HashSet<AstNode> visitedRoots = new HashSet<AstNode>();
-
 		void VisitIfNeccessary(AstNode rootNode)
 		{
 			// If any of the parent nodes are recorded as visited,
@@ -72,8 +71,7 @@ namespace ICSharpCode.NRefactory.CSharp.Refactoring
 				tmpRoot = tmpRoot.Parent;
 			}
 
-			rootNode.AcceptVisitor(locator);
-			visitedRoots.Add(rootNode);
+			locator.ProccessRoot (rootNode);
 		}
 
 		/// <summary>
@@ -93,15 +91,15 @@ namespace ICSharpCode.NRefactory.CSharp.Refactoring
 		/// searches, which references outside of <paramref name="rootNode"/> are
 		/// or are not reported is undefined.
 		/// </remarks>
-		public void FindReferences (AstNode rootNode, IVariable variable, FoundReferenceCallback action)
+		public IList<ReferenceResult> FindReferences(AstNode rootNode, IVariable variable)
 		{
-			VisitIfNeccessary(rootNode);
-			var lookup = (ILookup<IVariable, Tuple<AstNode, LocalResolveResult>>)references;
-			if (!lookup.Contains(variable))
-				return;
-			var iList = references[variable];
-			foreach (var reference in iList) {
-				action(reference.Item1, reference.Item2);
+			lock (locator) {
+				VisitIfNeccessary(rootNode);
+				var lookup = (ILookup<IVariable, ReferenceResult>)references;
+				if (!lookup.Contains(variable))
+					return new List<ReferenceResult>();
+				// Clone the list for thread safety
+				return references[variable].ToList();
 			}
 		}
 
@@ -119,11 +117,19 @@ namespace ICSharpCode.NRefactory.CSharp.Refactoring
 
 			IList<IVariable> processedVariables = new List<IVariable>();
 
+			public void ProccessRoot (AstNode rootNode)
+			{
+				rootNode.AcceptVisitor(this);
+				referenceFinder.visitedRoots.Add(rootNode);
+			}
+
 			protected override void VisitChildren(AstNode node)
 			{
+				if (referenceFinder.visitedRoots.Contains(node))
+					return;
 				var localResolveResult = resolver.Resolve(node) as LocalResolveResult;
 				if (localResolveResult != null && !processedVariables.Contains(localResolveResult.Variable)) {
-					referenceFinder.references.Add(localResolveResult.Variable, Tuple.Create(node, localResolveResult));
+					referenceFinder.references.Add(localResolveResult.Variable, new ReferenceResult(node, localResolveResult));
 
 					processedVariables.Add(localResolveResult.Variable);
 					base.VisitChildren(node);
@@ -135,4 +141,17 @@ namespace ICSharpCode.NRefactory.CSharp.Refactoring
 			}
 		}
 	}
+
+	public class ReferenceResult
+	{
+		public ReferenceResult (AstNode node, LocalResolveResult resolveResult)
+		{
+			Node = node;
+			ResolveResult = resolveResult;
+		}
+
+		public AstNode Node { get; private set; }
+
+		public LocalResolveResult ResolveResult { get; private set; }
+	}
 }