2 files changed, 12 insertions, 0 deletions
diff --git a/src/nvim/api/private/defs.h b/src/nvim/api/private/defs.h
index 76ac23a521..6c8e324649 100644
--- a/src/nvim/api/private/defs.h
+++ b/src/nvim/api/private/defs.h
@@ -22,6 +22,15 @@ typedef enum {
   kErrorTypeValidation
 } ErrorType;
 
+typedef enum {
+  kMessageTypeRequest,
+  kMessageTypeResponse,
+  kMessageTypeNotification
+} MessageType;
+
+/// Used as the message ID of notifications.
+#define NO_RESPONSE UINT64_MAX
+
 typedef struct {
   ErrorType type;
   char msg[1024];
diff --git a/src/nvim/api/private/helpers.c b/src/nvim/api/private/helpers.c
index 492da25a82..67ff77ebac 100644
--- a/src/nvim/api/private/helpers.c
+++ b/src/nvim/api/private/helpers.c
@@ -405,6 +405,9 @@ bool object_to_vim(Object obj, typval_T *tv, Error *err)
       tv->vval.v_number = obj.data.boolean;
       break;
 
+    case kObjectTypeBuffer:
+    case kObjectTypeWindow:
+    case kObjectTypeTabpage:
     case kObjectTypeInteger:
       if (obj.data.integer > INT_MAX || obj.data.integer < INT_MIN) {
         api_set_error(err, Validation, _("Integer value outside range"));