Trying to do compile time checking with 'const' type arguments.

struct ExposedSecret[T: AnyRegType]:
    var borrowed_value: T

    fn __init__(inout self, borrowed borrowed_value: T):
        self.borrowed_value = borrowed_value

struct Secret[T: AnyRegType, MEC: Int, EC: Int]:
    var inner: T

    fn __init__[EC: Int=EC](inout self, owned value: T):
        constrained[EC == 0, "`Secret[T, MEC, EC]` can only be constructed iff `EC == 0`"]()
        self.inner = value

    @staticmethod
    fn ec_add_one(owned other: Self) -> Secret[T, MEC, EC + 1]:
        return other^

    fn expose_secret[ReturnedType: AnyRegType](owned self, owned closure:
        fn(exposed_secret: ExposedSecret[T]) capturing -> ReturnedType) 
        -> ListLiteral[ReturnedType, Secret[T, MEC, EC + 1]]:
            constrained[EC < MEC, "`expose_secret` can only be called if `EC < MEC`"]()
            let returned_value = closure(ExposedSecret[T])
            let new_self = Secret.ec_add_one(self^)
            return [returned_value, new_self]

fn main():
    let my_secret = Secret[Int, 3, 2](69)
    
    @parameter
    fn capturing_closure_but_actually_never_capture(borrowed exposed_secret: ExposedSecret[Int]) -> Int:
        return exposed_secret.borrowed_value

    let my_69_secret_tuple = my_secret^.expose_secret[Int](capturing_closure_but_actually_never_capture)
    let returned_69_secret = my_69_secret_tuple.get[0, Int]()
    let my_new_secret = my_69_secret_tuple^.get[1, Secret[Int, 3, 3]]()

/root/mojo_projs/sosecrets-mojo/src/secret.mojo:42:70: error: invalid call to 'get': result cannot bind AnyRegType type to memory-only type 'Secret[Int, 3, 3]'
    let my_new_secret = my_69_secret_tuple^.get[1, Secret[Int, 3, 3]]()
                                          ~~~~~~~~~~~~~~~~~~~~~~~~~~~^~
/root/mojo_projs/sosecrets-mojo/src/secret.mojo:1:1: note: function declared here

^
mojo: error: failed to parse the provided Mojo