Fix tests update comments

integration-tests/upgradeable-contracts/set-code-hash-migration/e2e_tests.rs

@@ -12,21 +12,21 @@ async fn migration_works<Client: E2EBackend>(mut client: Client) -> E2EResult<()
         .submit()
         .await
         .expect("instantiate failed");
-    let mut call = contract.call::<Incrementer>();
+    let mut call_builder = contract.call_builder::<Incrementer>();
 
-    let get = call.get();
-    let get_res = client.call(&ink_e2e::alice(), &get).dry_run().await;
+    let get = call_builder.get();
+    let get_res = client.call(&ink_e2e::alice(), &get).dry_run().await?;
     assert_eq!(get_res.return_value(), 0);
 
-    let inc = call.inc();
+    let inc = call_builder.inc();
     let _inc_result = client
         .call(&ink_e2e::alice(), &inc)
         .submit()
         .await
         .expect("`inc` failed");
 
-    let get = call.get();
-    let get_res = client.call(&ink_e2e::alice(), &get).dry_run().await;
+    let get = call_builder.get();
+    let get_res = client.call(&ink_e2e::alice(), &get).dry_run().await?;
     let pre_migration_value = get_res.return_value();
     assert_eq!(pre_migration_value, 1);
 
@@ -50,7 +50,7 @@ async fn migration_works<Client: E2EBackend>(mut client: Client) -> E2EResult<()
     // When
 
     // Set the code hash to the migration contract
-    let set_code = call.set_code(migration_code_hash);
+    let set_code = call_builder.set_code(migration_code_hash);
     let _set_code_result = client
         .call(&ink_e2e::alice(), &set_code)
         .submit()
@@ -61,7 +61,7 @@ async fn migration_works<Client: E2EBackend>(mut client: Client) -> E2EResult<()
     // of the updated contract.
     const NEW_INC_BY: u8 = 4;
     let migrate = contract
-        .call::<migration::incrementer::Incrementer>()
+        .call_builder::<migration::incrementer::Incrementer>()
         .migrate(NEW_INC_BY, new_code_hash);
 
     let _migration_result = client
@@ -72,7 +72,7 @@ async fn migration_works<Client: E2EBackend>(mut client: Client) -> E2EResult<()
 
     // Then
     let inc = contract
-        .call::<updated_incrementer::incrementer::Incrementer>()
+        .call_builder::<updated_incrementer::incrementer::Incrementer>()
         .inc();
 
     let _inc_result = client
@@ -81,8 +81,8 @@ async fn migration_works<Client: E2EBackend>(mut client: Client) -> E2EResult<()
         .await
         .expect("`inc` failed");
 
-    let get = call.get();
-    let get_res = client.call(&ink_e2e::alice(), &get).dry_run().await;
+    let get = call_builder.get();
+    let get_res = client.call(&ink_e2e::alice(), &get).dry_run().await?;
 
     // Remember, we updated our incrementer contract to increment by `4`.
     assert_eq!(

integration-tests/upgradeable-contracts/set-code-hash-migration/migration/lib.rs

@@ -43,16 +43,22 @@ pub mod incrementer {
         /// # Note
         ///
         /// This function necessarily accepts a `&self` instead of a `&mut self` because
-        /// we are modifying storage directly for the migration. Using `&mut self`
-        /// would overwrite our migration changes with the contents of the
-        /// original `Incrementer`.
+        /// we are modifying storage directly for the migration.
+        ///
+        /// The `self` in `&mut self` is the original `Incrementer` storage struct, and
+        /// would be implicitly written to storage following the function execution,
+        /// overwriting the migrated storage.
         #[ink(message)]
         pub fn migrate(&self, inc_by: u8, code_hash: Hash) {
             let incrementer_new = IncrementerNew {
                 count: self.count as u64,
                 inc_by,
             };
-            const STORAGE_KEY: u32 = 0x00000000;
+
+            // overwrite the original storage struct with the migrated storage struct,
+            // which has a layout compatible with the new contract code.
+            const STORAGE_KEY: u32 =
+                <Incrementer as ink::storage::traits::StorageKey>::KEY;
             ink::env::set_contract_storage(&STORAGE_KEY, &incrementer_new);
 
             ink::env::set_code_hash::<<Self as ink::env::ContractEnv>::Env>(&code_hash)