diff --git a/Nodejs/Product/Analysis/Analysis/Analyzer/AnalysisUnit.cs b/Nodejs/Product/Analysis/Analysis/Analyzer/AnalysisUnit.cs
index 7cf38ec99..558882652 100644
--- a/Nodejs/Product/Analysis/Analysis/Analyzer/AnalysisUnit.cs
+++ b/Nodejs/Product/Analysis/Analysis/Analyzer/AnalysisUnit.cs
@@ -180,7 +180,7 @@ internal void Analyze(DDG ddg, CancellationToken cancel) {
                 long endTime = _sw.ElapsedMilliseconds;
                 var thisTime = endTime - startTime;
                 _analysisTime += thisTime;
-                if (thisTime >= 500 || (_analysisTime / _analysisCount) > 500) {                
+                if (thisTime >= 500 || (_analysisTime / _analysisCount) > 500) {
                     Trace.TraceWarning("Analyzed: {0} {1} ({2} count, {3}ms total, {4}ms mean)", this, thisTime, _analysisCount, _analysisTime, (double)_analysisTime / _analysisCount);
                 }
             }
@@ -188,9 +188,12 @@ internal void Analyze(DDG ddg, CancellationToken cancel) {
         }
 
         internal virtual void AnalyzeWorker(DDG ddg, CancellationToken cancel) {
-            if (Tree != ProjectEntry.Tree) {
-                // we were enqueued and a new version became available, don't re-analyze against
-                // the old version.
+            Debug.Assert(Ast != null, "Ast has unexpected null value");
+            Debug.Assert(ProjectEntry != null, "ProjectEntry has unexpected null value");
+
+            if (Ast == null || ProjectEntry == null || Tree != ProjectEntry.Tree) {
+                // analysis unit properties are invalid or we were enqueued and a new version became available
+                // don't re-analyze against the old version.
                 return;
             }
 
diff --git a/Nodejs/Product/Analysis/Analysis/VariableDef.cs b/Nodejs/Product/Analysis/Analysis/VariableDef.cs
index 217227ecc..b50664a08 100644
--- a/Nodejs/Product/Analysis/Analysis/VariableDef.cs
+++ b/Nodejs/Product/Analysis/Analysis/VariableDef.cs
@@ -180,7 +180,7 @@ protected virtual void ExceedsTypeLimit() {
                     if (type.Value == null) {
                         continue;
                     }
-                    if (analyzer == null && type.Value.DeclaringModule != null) {
+                    if (analyzer == null && type.Value != null && type.Value.DeclaringModule != null) {
                         analyzer = type.Value.DeclaringModule.Analysis.ProjectState;
                     }
                     var str = type.ToString();