Tag

        pub const Tag = enum(u8) {
            /// `data` is ignored.
            true,
            /// `data` is ignored.
            false,
            /// `data` is ignored.
            null,
            /// `data` is ignored.
            pos_inf,
            /// `data` is ignored.
            neg_inf,
            /// `data` is ignored.
            nan,
            /// `data` is the `i32` value.
            int_literal_small,
            /// `data` is index into `extra` of:
            /// * `limb_count: u32`
            /// * `limbs_idx: u32`
            int_literal_pos,
            /// Identical to `int_literal_pos`, except the value is negative.
            int_literal_neg,
            /// `data` is the `f32` value.
            float_literal_small,
            /// `data` is index into `extra` of 4 elements which are a bitcast `f128`.
            float_literal,
            /// `data` is the `u32` value.
            char_literal,
            /// `data` is a `NullTerminatedString`.
            enum_literal,
            /// `data` is index into `extra` of:
            /// * `start: u32`
            /// * `len: u32`
            string_literal,
            /// Null-terminated string literal,
            /// `data` is a `NullTerminatedString`.
            string_literal_null,
            /// An empty struct/array literal, `.{}`.
            /// `data` is ignored.
            empty_literal,
            /// `data` is index into `extra` of:
            /// * `elem_count: u32`
            /// * `first_elem: Node.Index`
            /// The nodes `first_elem .. first_elem + elem_count` are the children.
            array_literal,
            /// `data` is index into `extra` of:
            /// * `elem_count: u32`
            /// * `first_elem: Node.Index`
            /// * `field_name: NullTerminatedString` for each `elem_count`
            /// The nodes `first_elem .. first_elem + elem_count` are the children.
            struct_literal,
        }