Clippy warns about "the operation is ineffective" and unable to set `#[allow(...)]`

[TheAifam5]

Adding repr to the struct results in a clippy warning:

the operation is ineffective. Consider reducing it to `mregion: u8`

Adding #[allow(clippy::identity_op)] on top of the struct does not disable the warning.

Example (straight from the test):

use modular_bitfield::prelude::*;

#[bitfield]
#[repr(u32)]
#[derive(Debug, PartialEq, Eq)]
struct TtResp {
    mregion: u8,
    sregion: u8, 
    mrvalid: bool,
    srvalid: bool,
    r: bool,
    rw: bool,
    nsr: bool,
    nsrw: bool,
    s: bool,
    irvalid: bool,
    iregion: u8,
}

Rust: 1.52.0-nightly (d6eaea1c8 2021-03-14) Clippy: 0.1.52 (d6eaea1c 2021-03-14) Crate Version: 0.11.2

[MJDSys]

As a workaround until the PR is merged, if you specify the number of bits to use for the struct the clippy warning is also removed. The above code would change to:

#[bitfield(bits = 32)]
#[repr(u32)]
struct ...