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//! [`Err(E)`]: Err |
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//! [io::Error]: ../../std/io/struct.Error.html "io::Error" |
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//! |
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+//! # Representation |
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+//! |
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+//! In some cases, [`Result<T, E>`] will gain the same size, alignment, and ABI |
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+//! guarantees as [`Option`] has. One of either the `T` or `E` type must be a |
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+//! type that qualifies for the `Option` [representation guarantees][opt-rep], |
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+//! and the *other* type must meet all of the following conditions: |
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+//! * Is a zero-sized type with alignment 1 (a "1-ZST"). |
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+//! * Has no fields. |
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+//! * Does not have the `#[non_exhaustive]` attribute. |
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+//! |
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+//! For example, `NonZeroI32` qualifies for the `Option` representation |
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+//! guarantees, and `()` is a zero-sized type with alignment 1, no fields, and |
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+//! it isn't `non_exhaustive`. This means that both `Result<NonZeroI32, ()>` and |
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+//! `Result<(), NonZeroI32>` have the same size, alignment, and ABI guarantees |
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+//! as `Option`. The only difference is the implied semantics: |
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+//! * `Option` is "a non-zero i32 might be present" |
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+//! * `Result<NonZeroI32, ()>` is "a non-zero i32 success result, if any" |
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+//! * `Result<(), NonZeroI32>` is "a non-zero i32 error result, if any" |
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+//! |
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+//! [opt-rep]: ../option/index.html#representation "Option Representation" |
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+//! |
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//! # Method overview |
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//! |
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//! In addition to working with pattern matching, [`Result`] provides a |