The exceeding_bitshifts lint should fire on the following code, but it does not:

pub trait Foo {
    const N: i32;
}

impl<T: Foo> Foo for Vec<T> {
    const N: i32 = T::N << 42; // no warning here
}

Playground
(This testcase now exists in-tree as a FIXME in ui/lint/lint-exceeding-bitshifts.rs.)

Cc @oli-obk @wesleywiser

This issue has been assigned to @jumbatm via this comment.