Typed layouts

If the layout of an immutable type has one or more elided type parameters, the layout doesn't map to a single Julia type and can't implement ConstructType. This prevents us from using it as an argument type, despite the fact that it could be passed by value. Just like TypedValue let us annotate a Value with its type constructor, we can use TypedLayout to annotate a layout with its type constructor.

use jlrs::{
    data::{layout::typed_layout::TypedLayout, types::construct_type::ConstantBool},
    prelude::*,
};

#[repr(C)]
#[derive(Clone, Debug, Unbox, ValidLayout, Typecheck, ValidField, IsBits)]
#[jlrs(julia_type = "Main.JuliaModuleTutorial.HasElided")]
pub struct HasElided {
    pub a: i32,
}

#[derive(ConstructType, HasLayout)]
#[jlrs(
    julia_type = "Main.JuliaModuleTutorial.HasElided",
    constructor_for = "HasElided",
    scope_lifetime = false,
    data_lifetime = false,
    layout_params = [],
    elided_params = ["X"],
    all_params = ["X"]
)]
pub struct HasElidedTypeConstructor<X> {
    _x: ::std::marker::PhantomData<X>,
}

pub type HasElidedTrue = HasElidedTypeConstructor<ConstantBool<true>>;

fn get_inner(he: TypedLayout<HasElided, HasElidedTrue>) -> i32 {
    he.into_layout().a
}

julia_module! {
    become julia_module_tutorial_init_fn;

    fn get_inner(he: TypedLayout<HasElided, HasElidedTrue>) -> i32;
}

julia> module JuliaModuleTutorial
       using JlrsCore.Wrap

       struct HasElided{X}
           a::Int32
       end

       @wrapmodule("./target/debug/libjulia_module_tutorial", :julia_module_tutorial_init_fn)

       function __init__()
           @initjlrs
       end
       end
Main.JuliaModuleTutorial

julia> JuliaModuleTutorial.get_inner(JuliaModuleTutorial.HasElided{true}(1))
1

julia> JuliaModuleTutorial.get_inner(JuliaModuleTutorial.HasElided{1}(1))
ERROR: MethodError: no method matching get_inner(::Main.JuliaModuleTutorial.HasElided{1})

Closest candidates are:
  get_inner(::Main.JuliaModuleTutorial.HasElided{true})