E4021

The value identifier is unbound.

Erroneous Example

pub let a : Int = @bool.to_integer(true)

The example above tries to call the function to_integer in a package @bool, but this function is not present in the package @bool, giving the following error on line 1:

Value to_integer not found in package `bool`.

Suggestion

Make sure the identifier is correct.

In the above example, the method name should be to_int instead of to_integer:

pub let a : Int = true.to_int()