Cannot borrow self as mutable
WebMay 13, 2014 · 1. The problem here is just that closures do borrow their environment (not due to any form of uniqueness in that borrow); the closure's borrow conflicts with the mutable/unique borrow of self for self.link_concepts. I.e. it's the link_concepts call that is upsetting things. One would see identical behaviour (for the same reason) with just let x ... WebOct 2, 2024 · You can only borrow mutable variables as mutable and self is by default immutable, so either you need to make the function take mut self (as is suggested by the compiler) or make a new variable that is mutable (as in your original code). – SCappella Oct 2, 2024 at 3:24 self is not mutable since I passed it as immutable in the inputs.
Cannot borrow self as mutable
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WebIf you want to borrow the return without forcing the mutable borrow to live that long too, you are probably going to have to split the function in two. This is because you are not able to borrow the return value from the mutable borrow to do so. Share Improve this answer Follow edited Apr 19, 2024 at 21:35 Shepmaster 372k 85 1069 1321 WebDec 30, 2024 · &mut means exclusive mutable access. &mut self in a method call means it requires exclusive access to all of the object, all its fields, including self.context.. When …
WebMar 19, 2024 · Ok - let me see if I understand this. Since Rust no longer supports immutable struct fields, and apparently since the borrow checker does not perform interprocedural analysis, the compiler acts as if one of the &mut self methods could do something like:. self.classes[0] = SizeClass { sz : 50 } which would mean that if there were an alias to … WebThe compiler cannot infer a lifetime for the string borrow: error[E0106]: missing lifetime specifier --> src/main.rs:13:16 11 type Out = &String; ^ expected lifetime parameter I cannot figure out a way to explicitly state the lifetime of …
WebJul 25, 2024 · self.get_lat() borrows a value from &self, and that will restrict what else you can do with self until that borrow is released -- when your last goes out of scope at the … WebNov 19, 2024 · true_response holds a reference to Response, which means that as long as true_response exists, you cannot do a mutable borrow of Response, which is required by write_response. The issue is basically the same as in the following, hopefully simpler example ... fn write_response (self: &mut Response, true_response: &Response)
WebJul 25, 2024 · self.get_lat () borrows a value from &self, and that will restrict what else you can do with self until that borrow is released – when your last goes out of scope at the end of the function. If the compiler allowed you to call add_child, this could invalidate the immutable reference you have.
WebJul 9, 2024 · As you can see, you are borrowing self.test_vec mutably first, and then trying to get the length, which is another borrow. Since the first borrow is mutable and still in effect, the second borrow is illegal. When you use a temporary variable, you are effectively reordering your borrows and since self.test_vec.len() terminates the borrow before ... nourish kefir starter culturenourish kefir ukWebcannot borrow `*self` as immutable because it is also borrowed as mutable for number in &mut self.0 { ----- mutable borrow occurs here mutable borrow later used here *number = self.hello(); ^^^^^ immutable borrow occurs here. 我期待着它,但我没有看到任何其他方法来做到这一点。 how to sign in metamaskWebApr 8, 2024 · 1,462 2 22 51. "When I borrow a member of the struct, does Rust borrow the struct entirely?" Yes. This means the a method could hypothetically get a mutable reference to x, which would alias the reference you created with &a.x. – Coder-256. Apr 8, 2024 at 7:50. 1. It is possible to borrow &mut a.y and &a.x at the same time, so &a.x borrows ... how to sign in linkedinWebMar 18, 2024 · After reading up on mutable borrows in for loops it looks like this is the solution: fn place_animal_in_barn(&mut self, animal: Animal<'a>, placement: &str) { for barn in &mut self.barns { if barn.name == placement { barn.animals.push(animal); } } } how to sign in law in aslWebAnd when you call 'Post::add_text' you create a mutable reference to 'self', which naturally breaks the borrowing rules. I believe you are up against a fundamental flaw of Rust. … nourish kids programWebFeb 10, 2024 · 1. The closure passed to the get_or_insert_with method in Option is of type FnOnce - it thus consumes or moves the captured variables. In this case self is captured because of the usage of self.get_base_url () in the closure. However, since self is already borrowed, the closure cannot consume or move the value of self for unique … nourish kenny hills menu