extension_type_declares_member_of_object

Extension types can't declare members with the same name as a member declared by 'Object'.

The analyzer produces this diagnostic when the body of an extension type declaration contains a member with the same name as one of the members declared by Object.

The following code produces this diagnostic because the class Object already defines a member named hashCode:

extension type E(int i) {
  int get hashCode => 0;
}

If you need a member with the implemented semantics, then rename the member:

extension type E(int i) {
  int get myHashCode => 0;
}

If you don't need a member with the implemented semantics, then remove the member:

extension type E(int i) {}

Unless stated otherwise, the documentation on this site reflects Dart 3.7.3. Page last updated on 2025-05-08. View source or report an issue.