size_annotation_dimensions

'Array's must have an 'Array' annotation that matches the dimensions.

The analyzer produces this diagnostic when the number of dimensions specified in an Array annotation doesn't match the number of nested arrays specified by the type of a field.

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

The following code produces this diagnostic because the field a0 has a type with three nested arrays, but only two dimensions are given in the Array annotation:

import 'dart:ffi';

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

If the type of the field is correct, then fix the annotation to have the required number of dimensions:

import 'dart:ffi';

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

If the type of the field is wrong, then fix the type of the field:

import 'dart:ffi';

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

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.