//! A basic `Variable` implementation.
//!
//! Frontends can use any indexing scheme they see fit and
//! generate the appropriate `Variable` instances.
//!
//! Note: The `Variable` is used by Cranelift to index into densely allocated
//! arrays containing information about your mutable variables
//! Thus, make sure that Variable's indexes are allocated contiguously and
//! starting at `0`.
use u32;
use EntityRef;
///! An opaque reference to a variable.
;