Update packed storage examples

Author: davidsemakula

complex-storage-structures/README.md

@@ -80,19 +80,18 @@ struct MyStruct {
 }
 ```
 
-For [packed structs](https://use.ink/datastructures/storage-layout#packed-vs-non-packed-layout), a new trait was introduced - `Packed`. It represents structs,
-all fields of which occupy a single storage cell. Any type that implements
-`scale::Encode` and `scale::Decode` receives a `Packed` implementation:
+For [packed structs][Packed], a new trait was introduced - `Packed`. 
+It represents structs, all fields of which occupy a single storage cell. 
+Any type that implements `scale::Encode` and `scale::Decode` receives a `Packed` implementation:
 
-Unlike non-packed types created with `#[ink::storage_item]`, packed types don't have
-their own storage keys.
+Unlike non-packed types created with `#[ink::storage_item]`, 
+packed types don't have their own storage keys, 
+and they're created with `#[ink::storage_item(packed)]`.
+
+[Packed]: https://use.ink/datastructures/storage-layout#packed-vs-non-packed-layout
 
 ```rust
-#[derive(scale::Encode, scale::Decode)]
-#[cfg_attr(
-    feature = "std",
-    derive(scale_info::TypeInfo, ink::storage::traits::StorageLayout)
-)]
+#[ink::storage_item(packed)]
 struct MyPackedStruct {
     first_field: u32,
     second_field: Vec<u8>,
@@ -108,11 +107,7 @@ struct NonPacked {
     s2: Lazy<u128>,
 }
 
-#[derive(scale::Decode, scale::Encode)]
-#[cfg_attr(
-    feature = "std",
-    derive(scale_info::TypeInfo, ink::storage::traits::StorageLayout)
-)]
+#[ink::storage_item(packed)]
 struct Packed {
     s1: u128,
     s2: Vec<u128>,

complex-storage-structures/lib.rs

@@ -31,11 +31,8 @@ pub mod complex_structures {
         allowances: Mapping<(AccountId, AccountId), Balance, AutoKey>,
     }
 
-    #[derive(ink::scale::Encode, ink::scale::Decode, Default, Debug)]
-    #[cfg_attr(
-        feature = "std",
-        derive(ink::scale_info::TypeInfo, ink::storage::traits::StorageLayout)
-    )]
+    #[derive(Default, Debug)]
+    #[ink::storage_item(packed)]
     pub struct Balances {
         pub balance_state: u128,
     }

multisig/lib.rs

@@ -110,11 +110,8 @@ mod multisig {
     /// A Transaction is what every `owner` can submit for confirmation by other owners.
     /// If enough owners agree it will be executed by the contract.
     #[derive(Clone)]
-    #[cfg_attr(
-        feature = "std",
-        derive(Debug, PartialEq, Eq, ink::storage::traits::StorageLayout)
-    )]
-    #[ink::scale_derive(Encode, Decode, TypeInfo)]
+    #[cfg_attr(feature = "std", derive(Debug, PartialEq, Eq))]
+    #[ink::storage_item(packed)]
     pub struct Transaction {
         /// The address of the contract that is called in this transaction.
         pub callee: Address,
@@ -144,11 +141,8 @@ mod multisig {
     /// This is a book keeping struct that stores a list of all transaction ids and
     /// also the next id to use. We need it for cleaning up the storage.
     #[derive(Clone, Default)]
-    #[cfg_attr(
-        feature = "std",
-        derive(Debug, PartialEq, Eq, ink::storage::traits::StorageLayout)
-    )]
-    #[ink::scale_derive(Encode, Decode, TypeInfo)]
+    #[cfg_attr(feature = "std", derive(Debug, PartialEq, Eq))]
+    #[ink::storage_item(packed)]
     pub struct Transactions {
         /// Just store all transaction ids packed.
         transactions: Vec<TransactionId>,