invalid_ override_ of_ non_ virtual_ member
The member '{0}' is declared non-virtual in '{1}' and can't be overridden in subclasses.
Description
#
The analyzer produces this diagnostic when a member of a class, mixin, or
enum overrides a member that has the
@nonVirtual
annotation on it.
Example
#
The following code produces this diagnostic because the method
m
in
B
overrides the method
m
in
A
, and the method
m
in
A
is annotated
with the
@nonVirtual
annotation:
import 'package:meta/meta.dart';
class A {
@nonVirtual
void m() {}
}
class B extends A {
@override
void m() {}
}
Common fixes
#If the annotation on the method in the superclass is correct (the method in the superclass is not intended to be overridden), then remove or rename the overriding method:
import 'package:meta/meta.dart';
class A {
@nonVirtual
void m() {}
}
class B extends A {}
If the method in the superclass is intended to be overridden, then remove
the
@nonVirtual
annotation:
class A {
void m() {}
}
class B extends A {
@override
void m() {}
}
Unless stated otherwise, the documentation on this site reflects Dart 3.9.2. Page last updated on 2025-9-4. View source or report an issue.