The central type, TypeEq<_, _>, allows for zero-overhead, safe value coercions and is itself zero-sized.
Further, naming TypeEq<T, U> is well-formed for any types, but an inhabitant is available only if the
equality holds. For trait-level type equality, T: IsEqual<U> can be used.
The zero overhead claim can be seen in the provided benchmarks:
let eq = refl::<u32>().lift_through::<SliceF<BENCH_LEN>>();
b.iter(|| [0; BENCH_LEN]); // bench_no_coerce
b.iter(|| eq.coerce([0; BENCH_LEN])); // bench_coerce_array_refl
> running 2 tests
test benches::bench_no_coerce ... bench: 10,570 ns/iter (+/- 569)
test benches::bench_coerce_array_refl ... bench: 10,557 ns/iter (+/- 605)This crate is no-std and has a (default: enabled) feature for alloc features, i.e. coercing Box.
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