save-analysis: re-tokenisation error with `<<`

[nrc]

The following code causes an ICE

pub struct HuffmanTable {
    values: Vec<u8>,
    delta: [i32; 16],
    maxcode: [i32; 16],

    lut: [(u8, u8); 1 << LUT_BITS],
    ac_lut: Option<[(i16, u8); 1 << LUT_BITS]>,
}