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Rollup merge of #40131 - MajorBreakfast:patch-3, r=steveklabnik 

Make lifetime elision docs clearer

Previously it said
"It's forbidden to allow reasoning about types based on the item signature alone."

I think that sentence is wrong. Rust **uses** the item signatures to perform type inference within the body. I think what's meant is the other way around: It does not infer types for item signatures.

r? @steveklabnik
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Corey Farwell 2017-02-28 08:33:10 -05:00 committed by GitHub
parent c4b6c98f35 b70f929396
commit a851fc1441
1 changed files with 2 additions and 2 deletions
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src/doc/book/src/lifetimes.md
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@ -349,8 +349,8 @@ to it.
## Lifetime Elision
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.
Rust supports powerful local type inference in the bodies of functions, but it
deliberately does not perform any reasoning about types for item signatures.
However, for ergonomic reasons, a very restricted secondary inference algorithm called
“lifetime elision” does apply when judging lifetimes. Lifetime elision is concerned solely with inferring
lifetime parameters using three easily memorizable and unambiguous rules. This means lifetime elision