non_const_call_to_literal_constructor

This instance creation must be 'const', because the {0} constructor is marked as '@literal'.

The analyzer produces this diagnostic when a constructor that has the literal annotation is invoked without using the const keyword, but all of the arguments to the constructor are constants. The annotation indicates that the constructor should be used to create a constant value whenever possible.

The following code produces this diagnostic:

import 'package:meta/meta.dart';

class C {
  @literal
  const C();
}

C f() => C();

Add the keyword const before the constructor invocation:

import 'package:meta/meta.dart';

class C {
  @literal
  const C();
}

void f() => const C();