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Simplifying some of the phrasing explaining lifetime elision

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nicholasf 2016-03-23 04:58:59 +11:00
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14
src/doc/book/lifetimes.md
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@ -282,14 +282,12 @@ to it.
## Lifetime Elision
Rust supports powerful local type inference in function bodies, but it’s
forbidden in item signatures to allow reasoning about the types based on
the item signature alone. However, for ergonomic reasons a very restricted
secondary inference algorithm called “lifetime elision” applies in function
signatures. It infers only based on the signature components themselves and not
based on the body of the function, only infers lifetime parameters, and does
this with only three easily memorizable and unambiguous rules. This makes
lifetime elision a shorthand for writing an item signature, while not hiding
Rust supports powerful local type inference in the bodies of functions but not in their item signatures.
It's forbidden to allow reasoning about types based on the item signature alone.
However, for ergonomic reasons, a very restricted secondary inference algorithm called
“lifetime elision” does apply when judging lifetimes. Lifetime elision is concerned solely to infer
lifetime parameters using three easily memorizable and unambiguous rules. This means lifetime elision
acts as a shorthand for writing an item signature, while not hiding
away the actual types involved as full local inference would if applied to it.
When talking about lifetime elision, we use the term *input lifetime* and