make fileName in IDocument mandatory to avoid crashes

src/AddIns/BackendBindings/CSharpBinding/Project/Src/Parser/CSharpSymbolSearch.cs

@@ -104,9 +104,12 @@ namespace CSharpBinding
 				searchScope, parseInfo.UnresolvedFile, parseInfo.SyntaxTree, compilation,
 				delegate (AstNode node, ResolveResult result) {
 					if (document == null) {
-						document = new ReadOnlyDocument(textSource);
+						document = new ReadOnlyDocument(textSource, fileName);
 						highlighter = SD.EditorControlService.CreateHighlighter(document);
 					}
+					Identifier identifier = node.GetChildByRole(Roles.Identifier);
+					if (identifier != null)
+						node = identifier;
 					var region = new DomRegion(fileName, node.StartLocation, node.EndLocation);
 					int offset = document.GetOffset(node.StartLocation);
 					int length = document.GetOffset(node.EndLocation) - offset; 

src/AddIns/BackendBindings/CSharpBinding/Project/Src/Parser/Parser.cs

@@ -87,12 +87,12 @@ namespace CSharpBinding.Parser
 			else
 				parseInfo = new ParseInformation(file, fullParseInformationRequested);
 			
-			AddCommentTags(cu, parseInfo.TagComments, fileContent);
+			AddCommentTags(cu, parseInfo.TagComments, fileContent, parseInfo.FileName);
 			
 			return parseInfo;
 		}
 		
-		void AddCommentTags(SyntaxTree cu, IList<TagComment> tagComments, ITextSource fileContent)
+		void AddCommentTags(SyntaxTree cu, IList<TagComment> tagComments, ITextSource fileContent, FileName fileName)
 		{
 			ReadOnlyDocument document = null;
 			foreach (var comment in cu.Descendants.OfType<Comment>().Where(c => c.CommentType != CommentType.InactiveCode)) {
@@ -100,7 +100,7 @@ namespace CSharpBinding.Parser
 				int index = comment.Content.IndexOfAny(TaskListTokens, 0, out matchLength);
 				if (index > -1) {
 					if (document == null)
-						document = new ReadOnlyDocument(fileContent);
+						document = new ReadOnlyDocument(fileContent, fileName);
 					int commentSignLength = comment.CommentType == CommentType.Documentation || comment.CommentType == CommentType.MultiLineDocumentation ? 3 : 2;
 					int commentEndSignLength = comment.CommentType == CommentType.MultiLine || comment.CommentType == CommentType.MultiLineDocumentation ? 2 : 0;
 					int commentStartOffset = document.GetOffset(comment.StartLocation) + commentSignLength;
@@ -143,7 +143,7 @@ namespace CSharpBinding.Parser
 				variable, csParseInfo.UnresolvedFile, csParseInfo.SyntaxTree, compilation,
 				delegate (AstNode node, ResolveResult result) {
 					if (document == null) {
-						document = new ReadOnlyDocument(fileContent);
+						document = new ReadOnlyDocument(fileContent, parseInfo.FileName);
 						highlighter = SD.EditorControlService.CreateHighlighter(document);
 					}
 					var region = new DomRegion(parseInfo.FileName, node.StartLocation, node.EndLocation);

src/AddIns/BackendBindings/CSharpBinding/Project/Src/Refactoring/SDRefactoringContext.cs

@@ -108,21 +108,21 @@ namespace CSharpBinding.Refactoring
 		public override IDocumentLine GetLineByOffset(int offset)
 		{
 			if (document == null)
-				document = new ReadOnlyDocument(textSource);
+				document = new ReadOnlyDocument(textSource, resolver.UnresolvedFile.FileName);
 			return document.GetLineByOffset(offset);
 		}
 		
 		public override int GetOffset(TextLocation location)
 		{
 			if (document == null)
-				document = new ReadOnlyDocument(textSource);
+				document = new ReadOnlyDocument(textSource, resolver.UnresolvedFile.FileName);
 			return document.GetOffset(location);
 		}
 		
 		public override TextLocation GetLocation(int offset)
 		{
 			if (document == null)
-				document = new ReadOnlyDocument(textSource);
+				document = new ReadOnlyDocument(textSource, resolver.UnresolvedFile.FileName);
 			return document.GetLocation(offset);
 		}
 		

src/AddIns/BackendBindings/XamlBinding/XamlBinding/XamlParsedFile.cs

@@ -121,7 +121,7 @@ namespace ICSharpCode.XamlBinding
 			public XamlDocumentVisitor(IUnresolvedFile file, ITextSource fileContent)
 			{
 				this.file = file;
-				textDocument = new ReadOnlyDocument(fileContent);
+				textDocument = new ReadOnlyDocument(fileContent, file.FileName);
 			}
 			
 			public override void VisitDocument(AXmlDocument document)

src/AddIns/BackendBindings/XamlBinding/XamlBinding/XamlParser.cs

@@ -82,7 +82,7 @@ namespace ICSharpCode.XamlBinding
 				int index = comment.Value.IndexOfAny(TaskListTokens, 0, out matchLength);
 				if (index > -1) {
 					if (document == null)
-						document = fileContent as IDocument ?? new ReadOnlyDocument(fileContent);
+						document = fileContent as IDocument ?? new ReadOnlyDocument(fileContent, parseInfo.FileName);
 					do {
 						TextLocation startLocation = document.GetLocation(comment.StartOffset + index);
 						int startOffset = index + comment.StartOffset;

src/AddIns/BackendBindings/XamlBinding/XamlBinding/XamlResolver.cs

@@ -38,7 +38,7 @@ namespace ICSharpCode.XamlBinding
 			this.parseInfo = parseInfo;
 			this.location = location;
 			this.compilation = compilation;
-			textDocument = new ReadOnlyDocument(parseInfo.Text);
+			textDocument = new ReadOnlyDocument(parseInfo.Text, parseInfo.FileName);
 			offset = textDocument.GetOffset(location);
 			
 			AXmlObject innermost = parseInfo.Document.GetChildAtOffset(offset);

src/AddIns/BackendBindings/XamlBinding/XamlBinding/XamlSymbolSearch.cs

@@ -92,7 +92,7 @@ namespace ICSharpCode.XamlBinding
 			XamlResolver resolver = new XamlResolver();
 			do {
 				if (document == null) {
-					document = new ReadOnlyDocument(textSource);
+					document = new ReadOnlyDocument(textSource, fileName);
 					highlighter = SD.EditorControlService.CreateHighlighter(document);
 				}
 				var result = resolver.Resolve(parseInfo, document.GetLocation(offset + entity.Name.Length / 2 + 1), compilation, cancellationToken);

src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/AvalonEditorControlService.cs

@@ -2,6 +2,7 @@
 // This code is distributed under the GNU LGPL (for details please see \doc\license.txt)
 
 using System;
+using System.Diagnostics;
 using System.IO;
 using System.Linq;
 using ICSharpCode.AvalonEdit.AddIn.Options;
@@ -33,6 +34,7 @@ namespace ICSharpCode.AvalonEdit.AddIn
 		
 		public IHighlighter CreateHighlighter(IDocument document)
 		{
+			Debug.Assert(document.FileName != null, "FileName not set in " + document.GetType().FullName);
 			var def = HighlightingManager.Instance.GetDefinitionByExtension(Path.GetExtension(document.FileName));
 			var doc = document as TextDocument;
 			if (def == null || doc == null)

src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/ChangeMarkerMargin.cs

@@ -230,7 +230,7 @@ namespace ICSharpCode.AvalonEdit.AddIn
 					differ.editor.Visibility = Visibility.Collapsed;
 					differ.copyButton.Visibility = Visibility.Collapsed;
 				} else {
-					var baseDocument = new ReadOnlyDocument(changeWatcher.BaseDocument);
+					var baseDocument = new ReadOnlyDocument(changeWatcher.BaseDocument, TextView.Document.FileName);
 					if (differ.editor.SyntaxHighlighting != null) {
 						var mainHighlighter = new DocumentHighlighter(baseDocument, differ.editor.SyntaxHighlighting);
 						var popupHighlighter = differ.editor.TextArea.GetService(typeof(IHighlighter)) as DocumentHighlighter;

src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/DefaultChangeWatcher.cs

@@ -75,7 +75,7 @@ namespace ICSharpCode.AvalonEdit.AddIn
 			Stream baseFileStream = GetBaseVersion(fileName);
 			if (baseFileStream != null) {
 				// ReadAll() is taking care of closing the stream
-				baseDocument = new ReadOnlyDocument(ReadAll(baseFileStream));
+				baseDocument = new ReadOnlyDocument(ReadAll(baseFileStream), fileName);
 			} else {
 				// if the file is not under subversion, the document is the opened document
 				if (baseDocument == null) {

src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/XmlDoc/DocumentationUIBuilder.cs

@@ -200,7 +200,7 @@ namespace ICSharpCode.AvalonEdit.AddIn.XmlDoc
 		
 		public void AddCodeBlock(string textContent, bool keepLargeMargin = false)
 		{
-			var document = new ReadOnlyDocument(textContent);
+			var document = new ReadOnlyDocument(textContent, "");
 			var highlightingDefinition = HighlightingManager.Instance.GetDefinition("C#");
 			
 			var block = DocumentPrinter.ConvertTextDocumentToBlock(document, highlightingDefinition);

src/AddIns/Misc/SearchAndReplace/Project/Engine/SearchManager.cs

@@ -300,7 +300,7 @@ namespace SearchAndReplace
 					}
 					
 					// try to find a result
-					result = Find(file, new ReadOnlyDocument(buffer), searchOffset, length);
+					result = Find(file, new ReadOnlyDocument(buffer, file), searchOffset, length);
 					
 					i++;
 				}

src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Document/TextDocument.cs

@@ -81,17 +81,19 @@ namespace ICSharpCode.AvalonEdit.Document
 		/// Create an empty text document.
 		/// </summary>
 		public TextDocument()
-			: this(string.Empty)
+			: this("", "")
 		{
 		}
 		
 		/// <summary>
 		/// Create a new text document with the specified initial text.
 		/// </summary>
-		public TextDocument(IEnumerable<char> initialText, string fileName = null)
+		public TextDocument(IEnumerable<char> initialText, string fileName)
 		{
 			if (initialText == null)
 				throw new ArgumentNullException("initialText");
+			if (fileName == null)
+				throw new ArgumentNullException("fileName");
 			rope = new Rope<char>(initialText);
 			lineTree = new DocumentLineTree(this);
 			lineManager = new LineManager(lineTree, this);
@@ -108,7 +110,7 @@ namespace ICSharpCode.AvalonEdit.Document
 		/// <summary>
 		/// Create a new text document with the specified initial text.
 		/// </summary>
-		public TextDocument(ITextSource initialText, string fileName = null)
+		public TextDocument(ITextSource initialText, string fileName)
 			: this(GetTextFromTextSource(initialText), fileName)
 		{
 		}
@@ -351,7 +353,7 @@ namespace ICSharpCode.AvalonEdit.Document
 		/// <inheritdoc/>
 		public IDocument CreateDocumentSnapshot()
 		{
-			return new ReadOnlyDocument(this);
+			return new ReadOnlyDocument(this, fileName);
 		}
 		
 		/// <inheritdoc/>

src/Libraries/NRefactory/ICSharpCode.NRefactory/Editor/ReadOnlyDocument.cs

@@ -36,10 +36,12 @@ namespace ICSharpCode.NRefactory.Editor
 		/// <summary>
 		/// Creates a new ReadOnlyDocument from the given text source.
 		/// </summary>
-		public ReadOnlyDocument(ITextSource textSource, string fileName = null)
+		public ReadOnlyDocument(ITextSource textSource, string fileName)
 		{
 			if (textSource == null)
 				throw new ArgumentNullException("textSource");
+			if (fileName == null)
+				throw new ArgumentNullException("fileName");
 			// ensure that underlying buffer is immutable
 			this.textSource = textSource.CreateSnapshot();
 			this.fileName = fileName;
@@ -60,7 +62,7 @@ namespace ICSharpCode.NRefactory.Editor
 		/// <summary>
 		/// Creates a new ReadOnlyDocument from the given string.
 		/// </summary>
-		public ReadOnlyDocument(string text, string fileName = null)
+		public ReadOnlyDocument(string text, string fileName)
 			: this(new StringTextSource(text), fileName)
 		{
 		}

src/Libraries/NRefactory/ICSharpCode.NRefactory/Editor/StringBuilderDocument.cs

@@ -262,7 +262,7 @@ namespace ICSharpCode.NRefactory.Editor
 		public IDocument CreateDocumentSnapshot()
 		{
 			if (documentSnapshot == null)
-				documentSnapshot = new ReadOnlyDocument(this);
+				documentSnapshot = new ReadOnlyDocument(this, string.Empty);
 			return documentSnapshot;
 		}
 		

src/Main/Base/Project/Src/Editor/DocumentUtilitites.cs

@@ -26,7 +26,7 @@ namespace ICSharpCode.SharpDevelop.Editor
 		[Obsolete("Use the TextDocument constructor instead")]
 		public static IDocument LoadDocumentFromBuffer(ITextSource buffer)
 		{
-			return new TextDocument(buffer);
+			return new TextDocument(buffer, null);
 		}
 		
 		/// <summary>
@@ -35,7 +35,7 @@ namespace ICSharpCode.SharpDevelop.Editor
 		[Obsolete("Use the ReadOnlyDocument constructor instead")]
 		public static IDocument LoadReadOnlyDocumentFromBuffer(ITextSource buffer)
 		{
-			return new ReadOnlyDocument(buffer);
+			return new ReadOnlyDocument(buffer, null);
 		}
 		
 		/// <summary>

src/Main/Base/Project/Src/Gui/Pads/DefinitionViewPad.cs

@@ -127,7 +127,7 @@ namespace ICSharpCode.SharpDevelop.Gui
 		void LoadFile(string fileName)
 		{
 			// Load the text into the definition view's text editor.
-			ctl.Document = new TextDocument(SD.FileService.GetFileContent(fileName));
+			ctl.Document = new TextDocument(SD.FileService.GetFileContent(fileName), fileName);
 			currentFileName = fileName;
 			ctl.SyntaxHighlighting = HighlightingManager.Instance.GetDefinitionByExtension(Path.GetExtension(fileName));
 		}

src/Main/SharpDevelop/Workbench/WorkbenchStartup.cs

@@ -142,7 +142,7 @@ class Test {
 	void Main(string[] b) {
 	   SomeMethod(b[0 + 1]);
 	}
-}"), "test.cs");
+}", "test.cs"), "test.cs");
 			// warm up the type system
 			var unresolvedFile = cu.ToTypeSystem();
 			var pc = new ICSharpCode.NRefactory.CSharp.CSharpProjectContent().AddOrUpdateFiles(unresolvedFile);