extends_non_class

Classes can only extend other classes.

The analyzer produces this diagnostic when an extends clause contains a name that is declared to be something other than a class.

The following code produces this diagnostic because f is declared to be a function:

void f() {}

class C extends f {}

If you want the class to extend a class other than Object, then replace the name in the extends clause with the name of that class:

void f() {}

class C extends B {}

class B {}

If you want the class to extend Object, then remove the extends clause:

void f() {}

class C {}

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.