Why is Default not implemented for VecStorage?

[Tastaturtaste]

My use case is moving a DMatrix<f32> out of a struct with std::mem::take. This does not work however, results in the following error:

let mut X_samples = std::mem::take(&mut options.initial_points);
| -------------- ^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait Default is not implemented for VecStorage<f32, Dyn, Dyn>
| |
| required by a bound introduced by this call
|
= help: the trait Default is implemented for Matrix<T, R, C, S>
= note: required for Matrix<f32, Dyn, Dyn, VecStorage<f32, Dyn, Dyn>> to implement Default
note: required by a bound in std::mem::take
--> C:\Users\joshu.rustup\toolchains\stable-x86_64-pc-windows-msvc\lib/rustlib/src/rust\library\core\src\mem\mod.rs:838:16
|
838 | pub fn take<T: Default>(dest: &mut T) -> T {
| ^^^^^^^ required by this bound in take
For more information about this error, try rustc --explain E0277.

A quick look at the implementation of VecStorage makes it seem like it would be trivial to implement Default for it with an empty Vec. Is there a specific reason this was not done already I don't know?

[Tastaturtaste]

For reference, the implementation I expected would look like this:

impl<T, R: Dim, C: Dim> Default for VecStorage<T, R, C> {
    fn default() -> Self {
        Self {
            data: Default::default(),
            nrows: Dim::from_usize(0),
            ncols: Dim::from_usize(0),
        }
    }
}