Function unchecked_funnel_shl 

pub const unsafe fn unchecked_funnel_shl<T>(a: T, b: T, shift: u32) -> T
where
    T: FunnelShift,

🔬This is a nightly-only experimental API. (funnel_shifts #145686)

Funnel Shift left.

Concatenates a and b (with a in the most significant half), creating an integer twice as wide. Then shift this integer left by shift), and extract the most significant half. If a and b are the same, this is equivalent to a rotate left operation.

It is undefined behavior if shift is greater than or equal to the bit size of T.

Safe versions of this intrinsic are available on the integer primitives via the funnel_shl method. For example, u32::funnel_shl.