Fix microsoft#470 (microsoft#478)

jakebailey · Dec 10, 2018 · e534eae · e534eae
1 parent 9456d35
commit e534eae
Showing 1 changed file with 5 additions and 4 deletions.
diff --git a/src/Analysis/Engine/Impl/PythonAnalyzer.cs b/src/Analysis/Engine/Impl/PythonAnalyzer.cs
@@ -596,10 +596,11 @@ internal AnalysisValue GetCached(object key, Func<AnalysisValue> maker) {
 
         internal BuiltinInstanceInfo GetInstance(IPythonType type) => GetBuiltinType(type).Instance;
 
-        internal BuiltinClassInfo GetBuiltinType(IPythonType type) =>
-            (BuiltinClassInfo)GetCached(type,
-                () => MakeBuiltinType(type)
-            ) ?? ClassInfos[BuiltinTypeId.Object];
+        internal BuiltinClassInfo GetBuiltinType(IPythonType type)
+            // Cached value may or may not be a class info. Previous calls to GetAnalysisValueFromObjects
+            // may have cached a different object for the type. For example, IPythonFunction would cache
+            // BuiltinFunctionInfo and not BuiltinClassInfo. Therefore, don't use direct cast.
+            => GetCached(type, () => MakeBuiltinType(type)) as BuiltinClassInfo ?? MakeBuiltinType(type);
 
         private BuiltinClassInfo MakeBuiltinType(IPythonType type) {
             switch (type.TypeId) {