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minor improvement to Rc docs to avoid use of unwrap #15697

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minor improvement to Rc docs to avoid use of unwrap #15697

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5 changes: 3 additions & 2 deletions src/liballoc/rc.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -135,8 +135,9 @@ fn main() {
// that their object is still alive, we need to call upgrade() on them
// to turn them into a strong reference. This returns an Option, which
// contains a reference to our object if it still exists.
let gadget = gadget_opt.upgrade().unwrap();
println!("Gadget {} owned by {}", gadget.id, gadget.owner.name);
gadget_opt.upgrade().map(|gadget| {
println!("Gadget {} owned by {}", gadget.id, gadget.owner.name);
});
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@alexcrichton alexcrichton Jul 15, 2014

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I believe this example is showing how it is known for a fact that gadget_opt, while a weak pointer, is known to have at least one strong pointer floating around. I'm also not sure that map is the best way to handle options, but rather a match with a None case instead. In general map is used to produce Option<U> from Option<T>, but in this case it's being used in a more iterative context.

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@AlisdairO AlisdairO Jul 16, 2014

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Fair enough! It was suggested on reddit that unwrap should be avoided in general, and that using map was preferable. I'm happy to just close this to be honest.

}

// At the end of the method, gadget_owner, gadget1 and gadget2 get
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