Crate type_equalities

Implements type equalities that can be passed around and used at runtime to safely coerce values, references and other structures dependending on these types.

The equality type is zero-sized, and the coercion should optimize to a no-op in all cases.

Structs

ComposeF	Composition for TypeFunctions, i.e. ApF<ComposeF<F, G>, T> == ApF<F, ApF<G, T>>
IdF	Implements the identity TypeFunction, mapping types to itself. Coercing through this gives us the basic safe transmute.
LoefIdF	Implements a TypeFunction version of the Martin-Löf identity type, i.e. ApF<LoefIdF<T>, U> == TypeEq<T, U>.
MutRefF	Implements the TypeFunction ApF<MutRefF<'a>, A> == &'a mut A
RefF	Implements the TypeFunction ApF<RefF<'a>, A> == &'a A
TypeEq	Evidence of the equality T == U as a zero-sized type.

Traits

AliasSelf	Trait used to convince the rust type checker of the claimed equality
Consumer	A consumer recives evidence of a type equality T == U and computes a result.
TypeFunction	A trait mapping type arguments to results. Note that Self is used only as a marker. See also substitute, which implements coercing of results.

Functions

coerce	Coerce a value of type T to a value of type U, given evidence that T == U.
coerce_box	Coerce a value of type Box<T> to a value of type Box<U>, given evidence that T == U.
coerce_mut	Coerce a value of type &mut T to a value of type &mut U, given evidence that T == U.
coerce_ref	Coerce a value of type &T to a value of type &U, given evidence that T == U.
lift_equality	Lift the type equality through any TypeFunction
refl	Construct evidence of the reflexive equality T == T.
substitute	Our internal workhorse for most of the other coerce implementations, lifting the equality through an arbitrary TypeFunction. Do consider using this before writing a custom Consumer.

Type Definitions

ApF	The result of applying the TypeFunction F to T.