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Questions - borrow-checker

Rust borrow checker and early returns

Rust-lang Playground link struct Foo { val: i32 } impl Foo { pub fn maybe_get(&mut self) -> Option<&mut i32> { Some(&mut self.val) } pub fn definitel...
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quittle

rust

borrow-checker

mutable-reference

early-return

Votes: 0

Answers: 1

Latest Answer

I've managed to fix this with an unfortunately expensive alternative implementation due to how maybe_get is implemented in my non-trivial example. impl Foo { pub fn has_maybe_val(&self) -> ...
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quittle

Multiple mutable queries with Legion ECS

I am using the Legion ECS and trying to use multiple mutable queries and running into some borrow checker constraints. I basically want to update the state of components by comparing with all of the o...
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Toby Hede

rust

borrow-checker

entity-component-system

Votes: 0

Answers: 1

Latest Answer

The issue is that your components vector is a vector containing references to Component, which borrows from world and means you can't mutably borrow it later when you go to edit the component. You can...
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Colonel Thirty Two

Borrow error when attempting recursion on HashMap, where each value needs a reference to the map

I'm currently have an issue regarding Rust's borrowing policy. I have a HashMap of structs 'Value', each which contains a list of keys to other Values in HashMap. I am attempting to recursively call a...
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Dimitri_3gg

recursion

rust

hashmap

borrow-checker

Votes: 0

Answers: 1

Latest Answer

Below is a sample with a few variants: Non-performant and probably deadlock-prone but compiling version using Arc<Mutex> High-performance version using Vec and split_at_mut Highly unsafe, UB an...
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Mika Vatanen

Rust mutable references working in some cases but not in other cases

I've encountered a problem that I cannot understand involving mutable references and borrow checker. I am writing a naive binary search tree using safe rust. Full code can be seen here: https://github...
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Maksim Gayduk

rust

borrow-checker

Votes: 0

Answers: 2

Latest Answer

The main error here is that you have a &mut Option<Box<Node>>, but that doesn't makes much sense, you probably want an Option<&mut Box<Node>>. Thing of it as finding or...
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