Don't throw NotImplementedExceptions in IParser.ResolveSnippet() - see #399

Author: dgrunwald

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

@@ -130,7 +130,7 @@ public ICompilation CreateCompilationForSingleFile(FileName fileName, IUnresolve
 
 		public ResolveResult ResolveSnippet(ParseInformation parseInfo, TextLocation location, string codeSnippet, ICompilation compilation, CancellationToken cancellationToken)
 		{
-			throw new NotImplementedException();
+			return null;
 		}
 	}
 }

src/AddIns/DisplayBindings/ILSpyAddIn/ILSpyParser.cs

@@ -82,7 +82,7 @@ public ICodeContext ResolveContext(ParseInformation parseInfo, TextLocation loca
 
 		public ResolveResult ResolveSnippet(ParseInformation parseInfo, TextLocation location, string codeSnippet, ICompilation compilation, CancellationToken cancellationToken)
 		{
-			throw new NotImplementedException();
+			return null;
 		}
 
 		public void FindLocalReferences(ParseInformation parseInfo, ITextSource fileContent, IVariable variable, ICompilation compilation, Action<SearchResultMatch> callback, CancellationToken cancellationToken)

src/Main/Base/Project/Parser/IParser.cs

@@ -87,7 +87,7 @@ ParseInformation Parse(FileName fileName, ITextSource fileContent, bool fullPars
 
 		/// <summary>
 		/// Creates a compilation for a single file that does not belong to any project.
-		/// Used by <see cref="ParserService.GetCompilationForFile"/>.
+		/// Used by <see cref="IParserService.GetCompilationForFile"/>.
 		/// May return null if this operation is not supported.
 		/// </summary>
 		ICompilation CreateCompilationForSingleFile(FileName fileName, IUnresolvedFile unresolvedFile);

src/Main/SharpDevelop/Parser/ParserService.cs

@@ -328,7 +328,7 @@ public ResolveResult ResolveSnippet(FileName fileName, TextLocation fileLocation
 				compilation = GetCompilationForFile(fileName);
 			ResolveResult rr = entry.parser.ResolveSnippet(parseInfo, fileLocation, codeSnippet, compilation, cancellationToken);
 			LoggingService.Debug("Resolved " + fileLocation + " to " + rr);
-			return rr;
+			return rr ?? ErrorResolveResult.UnknownError;
 		}
 
 		public Task<ResolveResult> ResolveAsync(FileName fileName, TextLocation location, ITextSource fileContent, ICompilation compilation, CancellationToken cancellationToken)