cannot be dereferenced这个消息给了我们一个线索:我们需要实现Deref。实现Deref的简单东西有时被称为 "智能指针"。一个智能指针可以指向它的元素,有它的信息,并且可以使用它的方法。因为现在我们可以添加my_number.0,这是一个u8,但我们不能用HoldsANumber做其他的事情:到目前为止,它只有Debug。 有趣的是:String其...
error[E0614]: type `MyBox<{integer}>` cannot be dereferenced--> src/main.rs:32:19 | 32 | assert_eq!(5, *y);| ^^ MyBox<T>类型不能解引用,因为我们尚没在该类型实现这个功能。为了启用*运算符的解引用功能,需要实现Dereftrait。 通过实现Deref trait 将某类型像引用一样处理 为了实现trait,需...
error: type `MyBox<{integer}>` cannot be dereferenced --> src/main.rs:14:19 | 14 | assert_eq!(5, *y); | ^^ MyBox<T> 类型不能解引用我们并没有为其实现这个功能。为了启用 * 运算符的解引用功能,可以实现 Deref trait。 实现Deref trait 定义如何像引用一样对待某类型 如第十章所讨论的...
但我不理解它在处理将大量数据放入 HashMap的项目时，作者开始注意到 HashMap 占用了大量内存并对最小...
$cargo runCompiling deref-example v0.1.0 (file:///projects/deref-example) error[E0614]: type `MyBox<{integer}>` cannot be dereferenced-->src/main.rs:14:19| 14 | assert_eq!(5, *y); | ^^ For more information about this error, try `rustc --explain E0614`. error: could not co...
error[E0614]: type `i8` cannot be dereferenced --> src/main.rs:4:5 | 4 | assert_eq!(x, 0); | ^^^ | = note: this error originates in the macro `assert_eq` (in Nightly builds, run with -Z macro-backtrace for more info) The error message, ...
//[next]~| ERROR type `<dyn Iterator<Item = &'a mut u8> as IntoIterator>::Item` cannot be dereferenced // FIXME(-Znext-solver): these error messages are horrible and have to be // improved before we stabilize the new solver. //~^ ERROR `dyn Iterator<Item = &'a mut u8>` is...
This error indicates that a pointer to a trait type cannot be implicitly dereferenced by a pattern. Every trait defines a type, but because the size of trait implementors isn't fixed, this type has no compile-time size. Therefore, all accesses to trait types must be through pointers. If ...
We cannot // touch `refcount` after it's decremented to a non-zero value because another thread/CPU // may concurrently decrement it to zero and free it. It is ok to have a raw pointer to // freed/invalid memory as long as it is never dereferenced. let refcount = unsafe { self....
There is a comparable scenario for bothStringandStringsimilar to&stringwhere it can be dereferenced as&str. Example Code: fn main() { let mut os: String = "Welcome".to_owned(); let second_os: String = "Home".to_owned(); os.push_str(&second_os); ...