implement code issue to display syntax errors found by the Mono C# parser

src/AddIns/BackendBindings/CSharpBinding/Project/CSharpBinding.addin

@@ -203,6 +203,7 @@
 		<Class class = "ICSharpCode.NRefactory.CSharp.Refactoring.UseVarKeywordIssue" />
 		<Class class = "ICSharpCode.NRefactory.CSharp.Refactoring.ValueParameterUnusedIssue" />
 		<Class class = "ICSharpCode.NRefactory.CSharp.Refactoring.VariableDeclaredInWideScopeIssue" />
+		<Class class = "CSharpBinding.Refactoring.CSharpSyntaxIssue" />
 	</Path>
 	
 	<Path path = "/SharpDevelop/ViewContent/TextEditor/C#/ContextActions">

src/AddIns/BackendBindings/CSharpBinding/Project/CSharpBinding.csproj

@@ -74,6 +74,7 @@
     <Compile Include="Src\Completion\SegmentTrackingOutputFormatter.cs" />
     <Compile Include="Src\FormattingStrategy\CSharpFormatter.cs" />
     <Compile Include="Src\Parser\FoldingVisitor.cs" />
+    <Compile Include="Src\Refactoring\CSharpSyntaxIssue.cs" />
     <Compile Include="Src\Refactoring\InsertionPoint.cs" />
     <Compile Include="Src\Refactoring\IssueOptions.xaml.cs">
       <DependentUpon>IssueOptions.xaml</DependentUpon>

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

@@ -0,0 +1,50 @@
+// Copyright (c) AlphaSierraPapa for the SharpDevelop Team (for details please see \doc\copyright.txt)
+// This code is distributed under the GNU LGPL (for details please see \doc\license.txt)
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using ICSharpCode.AvalonEdit.Document;
+using ICSharpCode.NRefactory;
+using ICSharpCode.NRefactory.CSharp;
+using ICSharpCode.NRefactory.CSharp.Refactoring;
+using ICSharpCode.NRefactory.Editor;
+using ICSharpCode.NRefactory.TypeSystem;
+
+namespace CSharpBinding.Refactoring
+{
+	public class CSharpSyntaxIssue : ICodeIssueProvider
+	{
+		public IEnumerable<CodeIssue> GetIssues(BaseRefactoringContext context)
+		{
+			var refactoringContext = context as SDRefactoringContext;
+			if (refactoringContext == null)
+				return Enumerable.Empty<CodeIssue>();
+			
+			var syntaxTree = context.RootNode as SyntaxTree;
+			if (syntaxTree == null)
+				return Enumerable.Empty<CodeIssue>();
+
+			return syntaxTree.Errors.Select(error => CreateCodeIssue(error, refactoringContext));
+		}
+		
+		CodeIssue CreateCodeIssue(Error error, SDRefactoringContext context)
+		{
+			IDocument document = context.Document;
+			TextLocation begin = error.Region.Begin;
+			
+			int offset = document.GetOffset(begin.Line, begin.Column);
+			int endOffset = TextUtilities.GetNextCaretPosition(document, offset, System.Windows.Documents.LogicalDirection.Forward, CaretPositioningMode.WordBorderOrSymbol);
+			if (endOffset < 0) endOffset = document.TextLength;
+			int length = endOffset - offset;
+			
+			if (length < 2) {
+				// marker should be at least 2 characters long, but take care that we don't make
+				// it longer than the document
+				length = Math.Min(2, document.TextLength - offset);
+			}
+			
+			TextLocation end = document.GetLocation(offset + length);
+			return new CodeIssue(error.Message, begin, end);
+		}
+	}
+}