annotation_on_pointer_field

Fields in a struct class whose type is 'Pointer' shouldn't have any annotations.

The analyzer produces this diagnostic when a field that's declared in a subclass of Struct and has the type Pointer also has an annotation associated with it.

For more information about FFI, see C interop using dart:ffi.

The following code produces this diagnostic because the field p, which has the type Pointer and is declared in a subclass of Struct, has the annotation @Double():

import 'dart:ffi';

final class C extends Struct {
  @Double()
  external Pointer<Int8> p;
}

Remove the annotations from the field:

import 'dart:ffi';

final class C extends Struct {
  external Pointer<Int8> p;
}

Unless stated otherwise, the documentation on this site reflects Dart 3.8.0. Page last updated on 2025-05-08. View source or report an issue.