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July 8, 2024 12:38
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Rust: Object Safe Traits
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| // In general there are two properties for traits to satisfy | |
| // in order them to be object-safe: | |
| // | |
| // 1. The return type isn’t Self. | |
| // 2. There are no generic type parameters. | |
| // Here's an example of a non-object-safe Trait | |
| trait MyTrait { | |
| fn f(&self) -> Self; | |
| } | |
| impl MyTrait for u32 { | |
| fn f(&self) -> Self { 42 } | |
| } | |
| impl MyTrait for String { | |
| fn f(&self) -> Self { self.clone() } | |
| } | |
| // What should this function return? | |
| fn my_function(x: Box<dyn MyTrait>) -> ??? { | |
| x.f() | |
| } | |
| fn main() { | |
| my_function(Box::new(13_u32)); | |
| my_function(Box::new(String::from("abc"))); | |
| } |
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