@[email protected] to [email protected]English • 9 months agoCommon Rust Lifetime Misconceptions (2020)github.commessage-square5fedilinkarrow-up138arrow-down11cross-posted to: [email protected][email protected][email protected]
arrow-up137arrow-down1external-linkCommon Rust Lifetime Misconceptions (2020)github.com@[email protected] to [email protected]English • 9 months agomessage-square5fedilinkcross-posted to: [email protected][email protected][email protected]
minus-square@[email protected]linkfedilink1•edit-29 months agoThere are still obvious things the BC cannot get. For example: struct Foo; impl Foo { fn num(&mut self) -> usize { 0 } fn index(&mut self, _i: usize) { } } let foo = Foo; foo.index(foo.num()); //error
minus-square@[email protected]linkfedilink2•edit-29 months agoThis looks like a pretty easy fix that the compiler could do by extracting the argument to a temp variable to improve the syntax of the language.
minus-square@[email protected]linkfedilink1•edit-29 months agoNote that when you change num to take &self instead, this works out (you also need to mark foo as mutable, of course).
minus-square@[email protected]linkfedilink1•9 months agoIt’s a toy example. In that case, the solution is to assign the expression to a variable to compute its result upfront.
There are still obvious things the BC cannot get. For example:
struct Foo; impl Foo { fn num(&mut self) -> usize { 0 } fn index(&mut self, _i: usize) { } } let foo = Foo; foo.index(foo.num()); //error
This looks like a pretty easy fix that the compiler could do by extracting the argument to a temp variable to improve the syntax of the language.
Note that when you change
num
to take&self
instead, this works out (you also need to markfoo
as mutable, of course).It’s a toy example. In that case, the solution is to assign the expression to a variable to compute its result upfront.