ItemInfo

        pub const ItemInfo = packed struct(u32) {
            kind: ItemInfo.Kind,
            data: u30,

            pub const Kind = enum(u2) {
                enum_literal,
                error_value,
                body_len,
                under,
            };

            pub const Unwrapped = union(ItemInfo.Kind) {
                enum_literal: Zir.NullTerminatedString,
                error_value: Zir.NullTerminatedString,
                body_len: u32,
                under,
            };

            pub fn wrap(unwrapped: ItemInfo.Unwrapped) ItemInfo {
                const data_uncasted: u32 = switch (unwrapped) {
                    .enum_literal => |str_index| @backingInt(str_index),
                    .error_value => |str_index| @backingInt(str_index),
                    .body_len => |body_len| body_len,
                    .under => 0,
                };
                return .{ .kind = unwrapped, .data = @intCast(data_uncasted) };
            }

            pub fn unwrap(item_info: ItemInfo) ItemInfo.Unwrapped {
                return switch (item_info.kind) {
                    .enum_literal => .{ .enum_literal = @fromBackingInt(@intCast(item_info.data)) },
                    .error_value => .{ .error_value = @fromBackingInt(@intCast(item_info.data)) },
                    .body_len => .{ .body_len = item_info.data },
                    .under => .under,
                };
            }

            pub fn bodyLen(item_info: ItemInfo) ?u32 {
                return if (item_info.kind == .body_len) item_info.data else null;
            }
        }