diff --git a/src/vim9execute.c b/src/vim9execute.c
index bc4a1fc..f8ce101 100644
--- a/src/vim9execute.c
+++ b/src/vim9execute.c
@@ -5321,6 +5321,13 @@
 		    }
 
 		    object_T *obj = tv->vval.v_object;
+		    if (obj == NULL)
+		    {
+			SOURCING_LNUM = iptr->isn_lnum;
+			emsg(_(e_using_null_object));
+			goto on_error;
+		    }
+
 		    int idx;
 		    if (iptr->isn_type == ISN_GET_OBJ_MEMBER)
 			idx = iptr->isn_arg.number;