{"ast_node_type":"function","tokens":[{"end":81,"kind":"keyword","start":0,"text":"fn"}]}
    fn try_as_constant(&mut self, index: VnIndex) -> Option<ConstOperand<'tcx>> {
    /// If `index` is a `Value::Constant`, return the `Constant` to be put in the MIR.
        // This was already constant in MIR, do not change it. If the constant is not