Couple of minor fixes.

src/Compilers/Core/Portable/DiagnosticAnalyzer/AnalyzerDriver.cs

@@ -197,20 +197,21 @@ private Task ExecuteSyntaxTreeActions(CancellationToken cancellationToken)
 
             var addDiagnostic = GetDiagnosticSinkWithSuppression(analyzerDriver.DiagnosticQueue.Enqueue, newCompilation);
 
+            Action<Exception, DiagnosticAnalyzer, Diagnostic> newOnAnalyzerException;
             if (onAnalyzerException != null)
             {
                 // Wrap onAnalyzerException to pass in filtered diagnostic.
                 var comp = newCompilation;
-                onAnalyzerException = (ex, analyzer, diagnostic) => 
+                newOnAnalyzerException = (ex, analyzer, diagnostic) => 
                     onAnalyzerException(ex, analyzer, GetFilteredDiagnostic(diagnostic, comp));
             }
             else
             {
                 // Add exception diagnostic to regular diagnostic bag.
-                onAnalyzerException = (ex, analyzer, diagnostic) => addDiagnostic(diagnostic);
+                newOnAnalyzerException = (ex, analyzer, diagnostic) => addDiagnostic(diagnostic);
             }
 
-            var analyzerExecutor = AnalyzerExecutor.Create(newCompilation, options, addDiagnostic, onAnalyzerException, cancellationToken);
+            var analyzerExecutor = AnalyzerExecutor.Create(newCompilation, options, addDiagnostic, newOnAnalyzerException, cancellationToken);
             
             analyzerDriver.Initialize(newCompilation, analyzerExecutor, cancellationToken);
 

src/Test/Utilities/DiagnosticExtensions.cs

@@ -148,9 +148,10 @@ public static TCompilation VerifyDiagnostics<TCompilation>(this TCompilation c,
 
             var exceptionDiagnostics = new ConcurrentSet<Diagnostic>();
 
+            Action<Exception, DiagnosticAnalyzer, Diagnostic> newOnAnalyzerException;
             if (onAnalyzerException != null)
             {
-                onAnalyzerException = (ex, analyzer, diagnostic) =>
+                newOnAnalyzerException = (ex, analyzer, diagnostic) =>
                 {
                     exceptionDiagnostics.Add(diagnostic);
                     onAnalyzerException(ex, analyzer, diagnostic);
@@ -159,11 +160,11 @@ public static TCompilation VerifyDiagnostics<TCompilation>(this TCompilation c,
             else
             {
                 // We want unit tests to throw if any analyzer OR the driver throws, unless the test explicitly provides a delegate.
-                onAnalyzerException = RethrowAnalyzerException;
+                newOnAnalyzerException = RethrowAnalyzerException;
             }
 
             Compilation newCompilation;
-            var driver = AnalyzerDriver.Create(c, analyzersArray, options, AnalyzerManager.Instance, onAnalyzerException, out newCompilation, CancellationToken.None);
+            var driver = AnalyzerDriver.Create(c, analyzersArray, options, AnalyzerManager.Instance, newOnAnalyzerException, out newCompilation, CancellationToken.None);
             var discarded = newCompilation.GetDiagnostics();
             diagnostics = driver.GetDiagnosticsAsync().Result.AddRange(exceptionDiagnostics);