/// <summary> /// Return <see cref="DiagnosticAnalyzer.SupportedDiagnostics"/> of given <paramref name="analyzer"/>. /// </summary> public ImmutableArray <DiagnosticDescriptor> GetSupportedDiagnosticDescriptors( DiagnosticAnalyzer analyzer, AnalyzerExecutor analyzerExecutor) { var descriptors = _descriptorCache.GetOrAdd(analyzer, key => { var supportedDiagnostics = ImmutableArray <DiagnosticDescriptor> .Empty; // Catch Exception from analyzer.SupportedDiagnostics analyzerExecutor.ExecuteAndCatchIfThrowsAsync(analyzer, () => { var supportedDiagnosticsLocal = analyzer.SupportedDiagnostics; if (!supportedDiagnosticsLocal.IsDefaultOrEmpty) { supportedDiagnostics = supportedDiagnosticsLocal; } }).Wait(analyzerExecutor.CancellationToken); EventHandler <Exception> handler = null; Action <Exception, DiagnosticAnalyzer, Diagnostic> onAnalyzerException = analyzerExecutor.OnAnalyzerException; if (onAnalyzerException != null) { handler = new EventHandler <Exception>((sender, ex) => { var diagnostic = AnalyzerExecutor.CreateAnalyzerExceptionDiagnostic(analyzer, ex); onAnalyzerException(ex, analyzer, diagnostic); }); // Subscribe for exceptions from lazily evaluated localizable strings in the descriptors. foreach (var descriptor in supportedDiagnostics) { descriptor.Title.OnException += handler; descriptor.MessageFormat.OnException += handler; descriptor.Description.OnException += handler; } } return(Tuple.Create(supportedDiagnostics, handler)); }); return(descriptors.Item1); }