Why is padding required to be explicitly given for an array of struct?

[davids91]

With the following types:

#[derive(Clone, ShaderType)]
pub(crate) struct Element {
    pub(crate) albedo: bevy::color::Srgba,
    pub(crate) content: u32,
    _padding: bevy::math::Vec3,
}

#[derive(Resource, Clone, AsBindGroup, TypePath, ExtractResource)]
#[type_path = "MyStruct"]
pub struct MyStruct {
    #[storage(3, visibility(compute))]
    pub(crate) data_field: Vec<Element>,
}

In the shader:

@group(1) @binding(3)
var<storage, read_write> voxels: array<Element>;

Seem to work fine, but as soon as the data is reached the program crashes;

On the other hand if the _padding is removed, the following error is displayed upon pipeline validation:

Caused by:
    In Device::create_compute_pipeline
    Error matching shader requirements against the pipeline
    Shader global ResourceBinding { group: 1, binding: 3 } is not available in the pipeline layout
    Buffer structure size 32, added to one element of an unbound array, if it's the last field, ended up greater than the given `min_binding_size`