Some Result combinations work like an Option. · model-checking/verify-rust-std@43ae187 (original) (raw)

Original file line number	Diff line number	Diff line change
@@ -224,6 +224,21 @@
224	224	//! [`Err(E)`]: Err
225	225	//! [io::Error]: ../../std/io/struct.Error.html "io::Error"
226	226	//!
	227	+//! # Representation
	228	+//!
	229	+//! In some cases, [`Result<T, E>`] will gain the same size, alignment, and ABI
	230	+//! guarantees as [`Option`] has. One of either the `T` or `E` type must be a
	231	+//! type that qualifies for `Option` guarantees, and the other type must meet
	232	+//! all of the following conditions:
	233	+//! * Is a zero-sized type with alignment 1 (a "1-ZST").
	234	+//! * Has no fields.
	235	+//! * Does not have the #[non_exhaustive] attribute.
	236	+//!
	237	+//! For example, `Result<NonZeroI32, ()>` or `Result<(), NonZeroI32>` would both
	238	+//! have the same guarantees as `Option`. The only difference is the
	239	+//! implied semantics: `Result<NonZeroI32, ()>` is "a non-zero success value"
	240	+//! while `Result<(), NonZeroI32>` is "a non-zero error value".
	241	+//!
227	242	//! # Method overview
228	243	//!
229	244	//! In addition to working with pattern matching, [`Result`] provides a