Merge pull request #69791 from adamscott/fix-autocomplete-guess-crash

Fix autocomplete crash as it would infinite loop

modules/gdscript/gdscript_editor.cpp

@@ -1612,7 +1612,7 @@ static bool _guess_expression_type(GDScriptParser::CompletionContext &p_context,
 						}
 					}
 
-					if (!found) {
+					if (!found && base.value.get_type() != Variant::NIL) {
 						found = _guess_method_return_type_from_base(c, base, call->function_name, r_type);
 					}
 				}