extra_size_annotation_carray

'Array's must have exactly one 'Array' annotation.

The analyzer produces this diagnostic when a field in a subclass of Struct has more than one annotation describing the size of the native array.

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

The following code produces this diagnostic because the field a0 has two annotations that specify the size of the native array:

import 'dart:ffi';

final class C extends Struct {
  @Array(4)
  @Array(8)
  external Array<Uint8> a0;
}

Remove all but one of the annotations:

import 'dart:ffi';

final class C extends Struct {
  @Array(8)
  external Array<Uint8> a0;
}

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.