Dart: const variables must be initialized with a constant value

Question

Why there is an error, when the foo is already a const value?

const foo = const [10, 20];
const bar = foo[0] * 2; // error: const variables must be initialized with a constant value. 

Answer 1

That's because while the variables used to create your second constant are constants, you also used the operator [] – which is not compile-time constant.

So while you can do:

const a = 42;
const b = a * 3;

you cannot do:

const array = [42];
const b = a[0];

• user8234870: Its giving the same error for const String name = 1.toString();? Here 1 is a constant but dart is still its generating Const variables must be initialized with a constant value. Try changing the initializer to be a constant