Match arrays against byte strings

Hi,

Today i have to do this:

const MVHD: [u8;4] = *b"mvhd";
match header.id {
    BoxType::Id(BoxId(MVHD)) => self.mvhd = Some(MvhdBox::read(header, reader).await?),
    // Or
    BoxType::Id(BoxId([b'm', b'v', b'e', b'x'])) => self.mvex = Some(MvexBox::read(header, reader).await?),
    ...
}

When it would be reaonable and convenient to be able to do this:

match header.id {
    BoxType::Id(BoxId(b"mvhd")) => self.mvhd = Some(MvhdBox::read(header, reader).await?),
    BoxType::Id(BoxId(b"mvex")) => self.mvex = Some(MvexBox::read(header, reader).await?),
    ...
}

Today it gives:

BoxType::Id(BoxId(b"mvhd")) => self.mvhd = Some(MvhdBox::read(header, reader).await?),
                  ^^^^^^^ expected array `[u8; 4]`, found `&[u8; 4]`

Any plans on implementing a solution ?

Start with the issue's Rust examples comparing [u8; 4] constants and byte string literals in match patterns. Review the seven-comment discussion for the proposed behavior and constraints; done means an accepted language design or RFC specifying how these patterns should work.