rust - 从功能参数实现具有生命周期限制的切片的特征

Question

在以下代码段中，我正在尝试实现C:

// A
trait Get {
    fn get(slice: &[f32]) -> Self;
}

// B
impl Get for () {
    fn get(slice: &[f32]) -> Self {
        ()
    }
}

// C
impl Get for &[f32] {
    fn get(slice: &[f32]) -> Self {
        &slice[0..5]
    }
}

但是，这不起作用，因为借用检查器(正确地)提示外部 &[f32]的生存期与 slice的生存期不匹配。我如何表达这一点，最好不要改变其特质？
我尝试了以下方法，但没有结果:

// Doesn't work because the function signature differs from the Trait
impl<'a> Get for &'a [f32] {
    fn get(slice: &'a [f32]) -> Self {
        &slice[0..5]
    }
}

// Doesn't work, because the trait bound is not the same as the trait function
impl<'b> Get for &'b [f32] {
    fn get<'a>(slice: &'a [f32]) -> Self where 'a: 'b {
        &slice[0..5]
    }
}

Answer 1

如何在整个Get生命周期内使'a通用:

trait Get<'a> {
    fn get(slice: &'a [f32]) -> Self;
}

impl<'a> Get<'a> for () {
    fn get(slice: &'a [f32]) -> Self {
        ()
    }
}

impl<'a> Get<'a> for &'a [f32] {
    fn get(slice: &'a [f32]) -> Self {
        &slice[0..5]
    }
}