abi_specific_integer_invalid

Classes extending 'AbiSpecificInteger' must have exactly one const constructor, no other members, and no type parameters.

The analyzer produces this diagnostic when a class that extends AbiSpecificInteger doesn't meet all of the following requirements:

• there must be exactly one constructor
• the constructor must be marked const
• there must not be any members of other than the one constructor
• there must not be any type parameters

The following code produces this diagnostic because the class C doesn't define a const constructor:

import 'dart:ffi';

@AbiSpecificIntegerMapping({Abi.macosX64 : Int8()})
final class C extends AbiSpecificInteger {
}

The following code produces this diagnostic because the constructor isn't a const constructor:

import 'dart:ffi';

@AbiSpecificIntegerMapping({Abi.macosX64 : Int8()})
final class C extends AbiSpecificInteger {
  C();
}

The following code produces this diagnostic because the class C defines multiple constructors:

import 'dart:ffi';

@AbiSpecificIntegerMapping({Abi.macosX64 : Int8()})
final class C extends AbiSpecificInteger {
  const C.zero();
  const C.one();
}

The following code produces this diagnostic because the class C defines a field:

import 'dart:ffi';

@AbiSpecificIntegerMapping({Abi.macosX64 : Int8()})
final class C extends AbiSpecificInteger {
  final int i;

  const C(this.i);
}

The following code produces this diagnostic because the class C has a type parameter:

import 'dart:ffi';

@AbiSpecificIntegerMapping({Abi.macosX64 : Int8()})
final class C<T> extends AbiSpecificInteger { // type parameters
  const C();
}

Change the class so that it meets the requirements of having no type parameters and a single member that is a const constructor:

import 'dart:ffi';

@AbiSpecificIntegerMapping({Abi.macosX64 : Int8()})
final class C extends AbiSpecificInteger {
  const 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.