Workaround for #2682 and #2422 by simply clearing the TypeError

Author: bstaletic

include/pybind11/cast.h

@@ -1870,7 +1870,12 @@ struct arg_v : arg {
 #if !defined(NDEBUG)
         , type(type_id<T>())
 #endif
-    { }
+    {
+      // Workaround! See https://github.com/pybind/pybind11/issues/2336
+      if(PyErr_Occurred()) {
+        PyErr_Clear();
+      }
+    }
 
 public:
     /// Direct construction with name, default, and description