type_parameter_referenced_by_static

Static members can't reference type parameters of the class.

The analyzer produces this diagnostic when a static member references a type parameter that is declared for the class. Type parameters only have meaning for instances of the class.

The following code produces this diagnostic because the static method hasType has a reference to the type parameter T:

class C<T> {
  static bool hasType(Object o) => o is T;
}

If the member can be an instance member, then remove the keyword static:

class C<T> {
  bool hasType(Object o) => o is T;
}

If the member must be a static member, then make the member be generic:

class C<T> {
  static bool hasType<S>(Object o) => o is S;
}

Note, however, that there isn't a relationship between T and S, so this second option changes the semantics from what was likely to be intended.

Unless stated otherwise, the documentation on this site reflects Dart 3.8.1. Page last updated on 2025-05-08. View source or report an issue.