Improved performance of local variable renaming in big projects.

src/Libraries/NRefactory/ICSharpCode.NRefactory.CSharp/Resolver/FindReferenceSearchScope.cs

@@ -48,6 +48,12 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 		/// </summary>
 		ITypeDefinition TopLevelTypeDefinition { get; }
 		
+		/// <summary>
+		/// Gets the file name that defines the search scope.
+		/// If null, all files are searched.
+		/// </summary>
+		string FileName { get; }
+		
 		/// <summary>
 		/// Creates a navigator that can find references to this entity and reports
 		/// them to the specified callback.

src/Libraries/NRefactory/ICSharpCode.NRefactory.CSharp/Resolver/FindReferences.cs

@@ -151,6 +151,7 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 			internal ICompilation declarationCompilation;
 			internal Accessibility accessibility;
 			internal ITypeDefinition topLevelTypeDefinition;
+			internal string fileName;
 			
 			IResolveVisitorNavigator IFindReferenceSearchScope.GetNavigator(ICompilation compilation, FoundReferenceCallback callback)
 			{
@@ -179,6 +180,10 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 			ITypeDefinition IFindReferenceSearchScope.TopLevelTypeDefinition {
 				get { return topLevelTypeDefinition; }
 			}
+			
+			string IFindReferenceSearchScope.FileName {
+				get { return fileName; }
+			}
 		}
 		
 		abstract class FindReferenceNavigator : IResolveVisitorNavigator
@@ -233,12 +238,11 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 			}
 			SearchScope scope;
 			SearchScope additionalScope = null;
-			IEntity entity;
+			IEntity entity = null;
 
 			if (symbol.SymbolKind == SymbolKind.Variable) {
 				var variable = (IVariable) symbol;
 				scope = GetSearchScopeForLocalVariable(variable);
-				entity = null;
 			} else if (symbol.SymbolKind == SymbolKind.Parameter) {
 				var par = (IParameter)symbol;
 				scope = GetSearchScopeForParameter(par);
@@ -375,7 +379,10 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 						return pc.Files.OfType<CSharpUnresolvedFile>();
 				}
 			} else {
-				return pc.Files.OfType<CSharpUnresolvedFile>();
+				if (searchScope.FileName == null)
+					return pc.Files.OfType<CSharpUnresolvedFile>();
+				else
+					return pc.Files.OfType<CSharpUnresolvedFile>().Where(f => f.FileName == searchScope.FileName);
 			}
 		}
 		
@@ -1385,6 +1392,7 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 					return new FindLocalReferencesNavigator(variable);
 				}
 			);
+			scope.fileName = variable.Region.FileName;
 			return scope;
 		}
 		
@@ -1516,7 +1524,7 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 					return true;
 
 				var st = node as SimpleType;
-				if (st != null && st.Identifier == ns.Name) 
+				if (st != null && st.Identifier == ns.Name)
 					return !st.AncestorsAndSelf.TakeWhile (n => n is AstType).Any (m => m.Role == NamespaceDeclaration.NamespaceNameRole);
 
 				var mt = node as MemberType;
@@ -1542,7 +1550,7 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver
 			}
 		}
 		#endregion
-	
+		
 		#region Find Parameter References
 
 		SearchScope GetSearchScopeForParameter(IParameter parameter)