fix #299: Declare local variable: Automatic variable naming

src/Libraries/NRefactory/ICSharpCode.NRefactory.CSharp.Refactoring/CodeActions/DeclareLocalVariableAction.cs

@@ -72,6 +72,7 @@ namespace ICSharpCode.NRefactory.CSharp.Refactoring
 					guessedType = GetDelegateType(context, ((MethodGroupResolveResult)resolveResult).Methods.First(), expr);
 				}
 				var name = CreateMethodDeclarationAction.CreateBaseName(expr, guessedType);
+				name = context.GetLocalNameProposal(name, expr.StartLocation);
 				var type = context.UseExplicitTypes ? context.CreateShortType(guessedType) : new SimpleType("var");
 				var varDecl = new VariableDeclarationStatement(type, name, expr.Clone());
 				var replaceNode = visitor.Matches.First () as Expression;
@@ -100,6 +101,7 @@ namespace ICSharpCode.NRefactory.CSharp.Refactoring
 					}
 					var linkedNodes = new List<AstNode>();
 					var name = CreateMethodDeclarationAction.CreateBaseName(expr, guessedType);
+					name = context.GetLocalNameProposal(name, expr.StartLocation);
 					var type = context.UseExplicitTypes ? context.CreateShortType(guessedType) : new SimpleType("var");
 					var varDecl = new VariableDeclarationStatement(type, name, expr.Clone());
 					linkedNodes.Add(varDecl.Variables.First().NameToken);

src/Libraries/NRefactory/ICSharpCode.NRefactory.CSharp/Refactoring/BaseRefactoringContext.cs

@@ -214,6 +214,22 @@ namespace ICSharpCode.NRefactory.CSharp.Refactoring
 			} while (type.Members.Select (m => m.GetChildByRole (Roles.Identifier)).Any (n => n.Name == proposedName));
 			return proposedName;
 		}
+		
+		public virtual string GetLocalNameProposal (string name, TextLocation loc, bool camelCase = true)
+		{
+			string baseName = (camelCase ? char.ToLower (name [0]) : char.ToUpper (name [0])) + name.Substring (1);
+			var node = RootNode.GetNodeAt(loc);
+			if (node == null)
+				return baseName;
+			
+			var context = GetResolverStateBefore (node);
+			int number = -1;
+			string proposedName;
+			do {
+				proposedName = AppendNumberToName (baseName, number++);
+			} while (!(context.ResolveSimpleName (proposedName, EmptyList<IType>.Instance) is UnknownIdentifierResolveResult));
+			return proposedName;
+		}
 
 		static string AppendNumberToName (string baseName, int number)
 		{