{"ast_node_type":"variable","tokens":[{"end":83,"kind":"keyword","start":0,"text":"let"}]}
                let discr_bits = discr_val.to_scalar().to_bits(discr_layout.size)?;
                let discr_val = self.int_to_int_or_float(&tag_val, discr_layout).unwrap();
                // Convert discriminant to variant index, and catch invalid discriminants.