Questions tagged [coercion]
Coercion, type conversion and typecasting are different ways of, implicitly or explicitly, changing an entity of one data type into another.
coercion
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What does Rust error "you could box the found value and coerce it to the trait object" mean?
What does this error mean?
Reproduction
error[E0308]: mismatched types
--> src/main.rs:50:35
|
50 | PaymentType::InvoiceIn => InvoiceIn {
| ___________________________________^...
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25
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Understanding coercion of Box<Trait> to Box<dyn Trait> [duplicate]
I am just starting to learn Rust and if there is one topic that confused me it's coercion when it comes to trait objects.
trait Trait {
fn test(&self) -> ();
}
struct A{
num: u32
}
...
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votes
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34
views
How get an immutable Pin from a mutable Pin?
How to apply deref coercion from &mut to & for references that are wrapped inside Pin<>? That is, how to borrow Pin<&mut _> as Pin<&_>?
use std::pin::{Pin, pin};
fn ...
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0
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50
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How does Dereferencing with Traits and Trait functions with Slices and Arrays work
(I am new to rust and trying to write a little card game as an exercise and I might not have grasped some things correctly. I am trying to break down my problem/confusion as much as I can.)
I want to ...
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2
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34
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In R, how do you change the class of data in a matrix?
Say you have a matrix of logical values of size 6x4:
set.seed(4)
mat <- matrix(sample(c(T, F), 24, replace = T), ncol = 4)
mat
# [,1] [,2] [,3] [,4]
# [1,] FALSE TRUE FALSE FALSE
# [2,] ...
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71
views
Admissble type role overrides
In GHC Haskell, Map k v has a type role declaration for k to be nominal. This is because the user can otherwise coerce k to another type with the same representation but different Ord instance, ...
- 430
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0
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45
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Equivalent Casting of JPEG to Data, but with .mov files in Swift
I have some code that works fine, using Amplify to push and pull images from an AWS-S3 bucket.
let uploadTask = Amplify.Storage.uploadData(key: imageKey, data: srcData, options: nil)
Task {
...
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275
views
'length(x) = 2 > 1' in coercion to 'logical(1)'
I am getting above error whenever I am passing more than two conditions in if statement. I also tried 'all' instead of if statement but it also did not work.
Error is :
Warning in distType == "...
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26
views
Is there a way to get the data from an Applescript image (AXImage), perhaps using Applescript/Obj-C?
Hi there — I’m writing an Applescript that uses System Events to get an image:
tell application “System Events”
tell process “appName”
tell window 1
set theImage to image 1
...
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0
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61
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Is there a Rust signature signaling that any type that coerces into T would be allowed? [duplicate]
So I just started learning about Rust and the Implicit Deref Coercion. A "problem" I now often tumble over, is that this automatic deref does not work inside of other types, e.g. as Item ...
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134
views
Specify in Rust that a generic type supports coercion to a primitive type
In Rust, I have several different enums that are all #[repr(u32)], meaning I can use as to cast them to a u32:
#[repr(u32)]
enum Foo {A, B, C}
fn f(foo: Foo) {
dbg!(foo as u32);
}
Now I want to ...
- 173k
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votes
1
answer
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views
ToPrimitive VS OrdinaryToPrimitive
I am reading the Book, YDKJS by Kyle Simpson, topic Coercion. While looking at the specs I found that ToPrimitive calls OrdinaryToPrimitive conditionally. I read in a blog that:
JavaScript view ...
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1
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132
views
Why do I need to use `&` to trigger deref coercion in rust?
From The Rust Programming Language book:
Deref coercion converts a reference to a type that implements the
Deref trait into reference to another type
Questions in code snippet below:
Why & is ...
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272
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Why do I need to implement `From` for both a value and a reference? Shouldn't methods be automatically dereferenced or borrowed?
The behaviour of a Rust method call is described in The Rust Reference. It states that "when looking up a method call, the receiver may be automatically dereferenced or borrowed in order to call ...
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TS: Conditional property based on the value of a generic
Here I have a stripped down code snippet to demonstrate the sort of thing I'm trying to achieve:
interface A<RequiresB extends boolean = true> {
alwaysRequired: string
b: RequiresB extends ...
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