invalid_literal_annotation

Only const constructors can have the @literal annotation.

The analyzer produces this diagnostic when the literal annotation is applied to anything other than a const constructor.

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

import 'package:meta/meta.dart';

class C {
  @literal
  C();
}

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

import 'package:meta/meta.dart';

@literal
var x;

If the annotation is on a constructor and the constructor should always be invoked with const, when possible, then mark the constructor with the const keyword:

import 'package:meta/meta.dart';

class C {
  @literal
  const C();
}

If the constructor can't be marked as const, then remove the annotation.

If the annotation is on anything other than a constructor, then remove the annotation:

var x;