From 4adfa04dd361826c50c2f71b69372e5dfdd236a2 Mon Sep 17 00:00:00 2001
From: Dmitry Lavrenov <lawrenowdima@gmail.com>
Date: Mon, 7 Apr 2025 13:13:58 +0300
Subject: [PATCH 01/15] Introduce PrecompilesSet to config

---
 crates/pallet-evm-system/src/lib.rs | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/crates/pallet-evm-system/src/lib.rs b/crates/pallet-evm-system/src/lib.rs
index 172e651c5..b26b14779 100644
--- a/crates/pallet-evm-system/src/lib.rs
+++ b/crates/pallet-evm-system/src/lib.rs
@@ -3,7 +3,7 @@
 #![cfg_attr(not(feature = "std"), no_std)]
 
 use codec::{Decode, Encode, FullCodec, MaxEncodedLen};
-use frame_support::traits::StoredMap;
+use frame_support::traits::{StoredMap, TypedGet};
 use scale_info::TypeInfo;
 use sp_runtime::{
     traits::{One, Zero},
@@ -34,7 +34,7 @@ pub struct AccountInfo<Index, AccountData> {
 pub mod pallet {
     use frame_support::pallet_prelude::*;
     use sp_runtime::traits::{AtLeast32Bit, MaybeDisplay};
-    use sp_std::fmt::Debug;
+    use sp_std::{collections::btree_set::BTreeSet, fmt::Debug};
 
     use super::*;
 
@@ -72,6 +72,9 @@ pub mod pallet {
         /// pallet does regardless).
         type AccountData: Member + FullCodec + Clone + Default + TypeInfo + MaxEncodedLen;
 
+        /// A set of precompiles.
+        type PrecompilesSet: TypedGet<Type = BTreeSet<<Self as Config>::AccountId>>;
+
         /// Handler for when a new account has just been created.
         type OnNewAccount: OnNewAccount<<Self as Config>::AccountId>;
 
@@ -159,7 +162,7 @@ impl<T: Config> Pallet<T> {
 
     /// Create an account.
     pub fn create_account(who: &<T as Config>::AccountId) -> AccountCreationOutcome {
-        if Self::account_exists(who) {
+        if Self::account_exists(who) || T::PrecompilesSet::get().contains(who) {
             return AccountCreationOutcome::AlreadyExists;
         }
 
@@ -196,7 +199,7 @@ impl<T: Config> StoredMap<<T as Config>::AccountId, <T as Config>::AccountData>
                 Account::<T>::mutate(k, |a| a.data = data);
             }
             (None, true) => {
-                if nonce != <T as Config>::Index::zero() {
+                if nonce != <T as Config>::Index::zero() || T::PrecompilesSet::get().contains(k) {
                     Account::<T>::mutate(k, |a| a.data = Default::default());
                 } else {
                     Account::<T>::remove(k);

From 13859237ee1c028fca80e95d61503e37441cce0c Mon Sep 17 00:00:00 2001
From: Dmitry Lavrenov <lawrenowdima@gmail.com>
Date: Mon, 7 Apr 2025 13:14:24 +0300
Subject: [PATCH 02/15] Add PrecompilesSet data for mock env

---
 Cargo.lock                           |  1 +
 crates/pallet-evm-system/Cargo.toml  |  1 +
 crates/pallet-evm-system/src/mock.rs | 16 ++++++++++++++--
 3 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index f453a2ca1..0a6b1d73b 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -6174,6 +6174,7 @@ dependencies = [
  "fp-evm",
  "frame-support",
  "frame-system",
+ "hex-literal",
  "mockall",
  "parity-scale-codec",
  "scale-info",
diff --git a/crates/pallet-evm-system/Cargo.toml b/crates/pallet-evm-system/Cargo.toml
index 2e00f444f..5f3cbaa05 100644
--- a/crates/pallet-evm-system/Cargo.toml
+++ b/crates/pallet-evm-system/Cargo.toml
@@ -14,6 +14,7 @@ sp-runtime = { workspace = true }
 sp-std = { workspace = true }
 
 [dev-dependencies]
+hex-literal = { workspace = true }
 mockall = { workspace = true }
 sp-core = { workspace = true }
 sp-io = { workspace = true }
diff --git a/crates/pallet-evm-system/src/mock.rs b/crates/pallet-evm-system/src/mock.rs
index 8beb62295..ec2d282c7 100644
--- a/crates/pallet-evm-system/src/mock.rs
+++ b/crates/pallet-evm-system/src/mock.rs
@@ -1,4 +1,7 @@
-use frame_support::traits::{ConstU32, ConstU64};
+use frame_support::{
+    parameter_types,
+    traits::{ConstU32, ConstU64},
+};
 use mockall::mock;
 use sp_core::{H160, H256};
 use sp_runtime::{
@@ -6,7 +9,7 @@ use sp_runtime::{
     traits::{BlakeTwo256, IdentityLookup},
     BuildStorage,
 };
-use sp_std::{boxed::Box, prelude::*};
+use sp_std::{boxed::Box, collections::btree_set::BTreeSet, prelude::*};
 
 use crate::{self as pallet_evm_system, *};
 
@@ -69,11 +72,20 @@ impl frame_system::Config for Test {
     type MaxConsumers = ConstU32<16>;
 }
 
+pub const PRECOMPILE: H160 = H160(hex_literal::hex!(
+    "7000000000000000000000000000000000000007"
+));
+
+parameter_types! {
+    pub PrecompilesSet: BTreeSet<H160> = BTreeSet::from([PRECOMPILE]);
+}
+
 impl pallet_evm_system::Config for Test {
     type RuntimeEvent = RuntimeEvent;
     type AccountId = H160;
     type Index = u64;
     type AccountData = u64;
+    type PrecompilesSet = PrecompilesSet;
     type OnNewAccount = MockDummyOnNewAccount;
     type OnKilledAccount = MockDummyOnKilledAccount;
 }

From ca904a8f91ed7766750a53471a4e0408c91add55 Mon Sep 17 00:00:00 2001
From: Dmitry Lavrenov <lawrenowdima@gmail.com>
Date: Mon, 7 Apr 2025 13:28:54 +0300
Subject: [PATCH 03/15] Add tests

---
 crates/pallet-evm-system/src/tests.rs | 58 +++++++++++++++++++++++++++
 1 file changed, 58 insertions(+)

diff --git a/crates/pallet-evm-system/src/tests.rs b/crates/pallet-evm-system/src/tests.rs
index c8d6c51fd..8ef30860b 100644
--- a/crates/pallet-evm-system/src/tests.rs
+++ b/crates/pallet-evm-system/src/tests.rs
@@ -67,6 +67,27 @@ fn create_account_already_exists() {
     });
 }
 
+/// This test verifies that trying creating an precompiled account works as expected.
+#[test]
+fn create_precompiled_account_already_exists() {
+    new_test_ext().execute_with_ext(|_| {
+        // Set block number to enable events.
+        System::set_block_number(1);
+
+        // Invoke the function under test.
+        assert_storage_noop!(assert_eq!(
+            EvmSystem::create_account(&PRECOMPILE),
+            AccountCreationOutcome::AlreadyExists
+        ));
+
+        // Assert that there is no a corresponding `NewAccount` event.
+        assert!(System::events().iter().all(|record| record.event
+            != RuntimeEvent::EvmSystem(Event::NewAccount {
+                account: PRECOMPILE,
+            })));
+    });
+}
+
 /// This test verifies that incrementing account nonce works in the happy path
 /// in case a new account should be created.
 #[test]
@@ -296,6 +317,43 @@ fn try_mutate_exists_account_retained() {
     });
 }
 
+/// This test verifies that `try_mutate_exists` works as expected in case data was providing
+/// and returned data is `None`, account is precompiled. As a result, the account has been retained.
+#[test]
+fn try_mutate_exists_precompiled_account_retained() {
+    new_test_ext().execute_with_ext(|_| {
+        // Prepare test data.
+        let nonce = 0;
+        let data = 100;
+
+        let account_info = AccountInfo { nonce, data };
+        <Account<Test>>::insert(PRECOMPILE, account_info);
+
+        // Check test preconditions.
+        assert!(EvmSystem::account_exists(&PRECOMPILE));
+
+        // Set block number to enable events.
+        System::set_block_number(1);
+
+        // Invoke the function under test.
+        EvmSystem::try_mutate_exists(&PRECOMPILE, |maybe_data| -> Result<(), DispatchError> {
+            *maybe_data = None;
+            Ok(())
+        })
+        .unwrap();
+
+        // Assert state changes.
+        assert!(EvmSystem::account_exists(&PRECOMPILE));
+        assert_eq!(<Account<Test>>::get(PRECOMPILE), AccountInfo::default());
+
+        // Assert that there is no a corresponding `KilledAccount` event.
+        assert!(System::events().iter().all(|record| record.event
+            != RuntimeEvent::EvmSystem(Event::KilledAccount {
+                account: PRECOMPILE,
+            })));
+    });
+}
+
 /// This test verifies that `try_mutate_exists` works as expected in case data wasn't providing
 /// and returned data is `None`. As a result, the account hasn't been created.
 #[test]

From 599da73d41dd39ed67ebd5bb4367aa90d464b4b1 Mon Sep 17 00:00:00 2001
From: Dmitry Lavrenov <lawrenowdima@gmail.com>
Date: Tue, 8 Apr 2025 17:28:47 +0300
Subject: [PATCH 04/15] Introduce own PrecompilesSet trait

---
 crates/pallet-evm-system/src/lib.rs | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/crates/pallet-evm-system/src/lib.rs b/crates/pallet-evm-system/src/lib.rs
index b26b14779..f48ceb4fc 100644
--- a/crates/pallet-evm-system/src/lib.rs
+++ b/crates/pallet-evm-system/src/lib.rs
@@ -3,7 +3,7 @@
 #![cfg_attr(not(feature = "std"), no_std)]
 
 use codec::{Decode, Encode, FullCodec, MaxEncodedLen};
-use frame_support::traits::{StoredMap, TypedGet};
+use frame_support::traits::StoredMap;
 use scale_info::TypeInfo;
 use sp_runtime::{
     traits::{One, Zero},
@@ -27,6 +27,14 @@ pub struct AccountInfo<Index, AccountData> {
     pub data: AccountData,
 }
 
+/// A set of precompiles.
+///
+/// Checks if the provided account is in the precompile set.
+pub trait PrecompilesSet<AccountId> {
+    /// Check if the given account is a precompile.
+    fn is_precompile(account_id: &AccountId) -> bool;
+}
+
 // We have to temporarily allow some clippy lints. Later on we'll send patches to substrate to
 // fix them at their end.
 #[allow(clippy::missing_docs_in_private_items)]
@@ -34,7 +42,7 @@ pub struct AccountInfo<Index, AccountData> {
 pub mod pallet {
     use frame_support::pallet_prelude::*;
     use sp_runtime::traits::{AtLeast32Bit, MaybeDisplay};
-    use sp_std::{collections::btree_set::BTreeSet, fmt::Debug};
+    use sp_std::fmt::Debug;
 
     use super::*;
 
@@ -73,7 +81,7 @@ pub mod pallet {
         type AccountData: Member + FullCodec + Clone + Default + TypeInfo + MaxEncodedLen;
 
         /// A set of precompiles.
-        type PrecompilesSet: TypedGet<Type = BTreeSet<<Self as Config>::AccountId>>;
+        type PrecompilesSet: PrecompilesSet<<Self as Config>::AccountId>;
 
         /// Handler for when a new account has just been created.
         type OnNewAccount: OnNewAccount<<Self as Config>::AccountId>;
@@ -162,7 +170,7 @@ impl<T: Config> Pallet<T> {
 
     /// Create an account.
     pub fn create_account(who: &<T as Config>::AccountId) -> AccountCreationOutcome {
-        if Self::account_exists(who) || T::PrecompilesSet::get().contains(who) {
+        if Self::account_exists(who) || T::PrecompilesSet::is_precompile(who) {
             return AccountCreationOutcome::AlreadyExists;
         }
 
@@ -199,7 +207,7 @@ impl<T: Config> StoredMap<<T as Config>::AccountId, <T as Config>::AccountData>
                 Account::<T>::mutate(k, |a| a.data = data);
             }
             (None, true) => {
-                if nonce != <T as Config>::Index::zero() || T::PrecompilesSet::get().contains(k) {
+                if nonce != <T as Config>::Index::zero() || T::PrecompilesSet::is_precompile(k) {
                     Account::<T>::mutate(k, |a| a.data = Default::default());
                 } else {
                     Account::<T>::remove(k);

From 1fb7572636472b97471cbbcbce09efdd010fcb0a Mon Sep 17 00:00:00 2001
From: Dmitry Lavrenov <lawrenowdima@gmail.com>
Date: Tue, 8 Apr 2025 17:40:52 +0300
Subject: [PATCH 05/15] Adapt mock with introduced trait

---
 crates/pallet-evm-system/src/mock.rs | 20 +++++++++-----------
 1 file changed, 9 insertions(+), 11 deletions(-)

diff --git a/crates/pallet-evm-system/src/mock.rs b/crates/pallet-evm-system/src/mock.rs
index ec2d282c7..8df71e0e5 100644
--- a/crates/pallet-evm-system/src/mock.rs
+++ b/crates/pallet-evm-system/src/mock.rs
@@ -1,7 +1,4 @@
-use frame_support::{
-    parameter_types,
-    traits::{ConstU32, ConstU64},
-};
+use frame_support::traits::{ConstU32, ConstU64};
 use mockall::mock;
 use sp_core::{H160, H256};
 use sp_runtime::{
@@ -9,7 +6,7 @@ use sp_runtime::{
     traits::{BlakeTwo256, IdentityLookup},
     BuildStorage,
 };
-use sp_std::{boxed::Box, collections::btree_set::BTreeSet, prelude::*};
+use sp_std::{boxed::Box, prelude::*};
 
 use crate::{self as pallet_evm_system, *};
 
@@ -72,12 +69,13 @@ impl frame_system::Config for Test {
     type MaxConsumers = ConstU32<16>;
 }
 
-pub const PRECOMPILE: H160 = H160(hex_literal::hex!(
-    "7000000000000000000000000000000000000007"
-));
+mock! {
+    #[derive(Debug)]
+    pub PrecompilesSet {}
 
-parameter_types! {
-    pub PrecompilesSet: BTreeSet<H160> = BTreeSet::from([PRECOMPILE]);
+    impl PrecompilesSet<H160> for PrecompilesSet {
+        pub fn is_precompile(who: &H160) -> bool;
+    }
 }
 
 impl pallet_evm_system::Config for Test {
@@ -85,7 +83,7 @@ impl pallet_evm_system::Config for Test {
     type AccountId = H160;
     type Index = u64;
     type AccountData = u64;
-    type PrecompilesSet = PrecompilesSet;
+    type PrecompilesSet = MockPrecompilesSet;
     type OnNewAccount = MockDummyOnNewAccount;
     type OnKilledAccount = MockDummyOnKilledAccount;
 }

From 5057eca78cd7177f7de59d122183803d0f98ce13 Mon Sep 17 00:00:00 2001
From: Dmitry Lavrenov <lawrenowdima@gmail.com>
Date: Tue, 8 Apr 2025 17:41:33 +0300
Subject: [PATCH 06/15] Properly use mock expectations in tests

---
 crates/pallet-evm-system/src/tests.rs | 57 +++++++++++++++++++++++----
 1 file changed, 49 insertions(+), 8 deletions(-)

diff --git a/crates/pallet-evm-system/src/tests.rs b/crates/pallet-evm-system/src/tests.rs
index 8ef30860b..c6a014796 100644
--- a/crates/pallet-evm-system/src/tests.rs
+++ b/crates/pallet-evm-system/src/tests.rs
@@ -22,6 +22,13 @@ fn create_account_created() {
         System::set_block_number(1);
 
         // Set mock expectations.
+        let is_precompile_ctx = MockPrecompilesSet::is_precompile_context();
+        is_precompile_ctx
+            .expect()
+            .once()
+            .with(predicate::eq(account_id))
+            .return_const(false);
+
         let on_new_account_ctx = MockDummyOnNewAccount::on_new_account_context();
         on_new_account_ctx
             .expect()
@@ -46,6 +53,7 @@ fn create_account_created() {
         }));
 
         // Assert mock invocations.
+        is_precompile_ctx.checkpoint();
         on_new_account_ctx.checkpoint();
     });
 }
@@ -71,20 +79,33 @@ fn create_account_already_exists() {
 #[test]
 fn create_precompiled_account_already_exists() {
     new_test_ext().execute_with_ext(|_| {
+        let precompile = H160::from_str("1000000000000000000000000000000000000001").unwrap();
+
+        // Set mock expectations.
+        let is_precompile_ctx = MockPrecompilesSet::is_precompile_context();
+        is_precompile_ctx
+            .expect()
+            .once()
+            .with(predicate::eq(precompile))
+            .return_const(true);
+
         // Set block number to enable events.
         System::set_block_number(1);
 
         // Invoke the function under test.
         assert_storage_noop!(assert_eq!(
-            EvmSystem::create_account(&PRECOMPILE),
+            EvmSystem::create_account(&precompile),
             AccountCreationOutcome::AlreadyExists
         ));
 
         // Assert that there is no a corresponding `NewAccount` event.
         assert!(System::events().iter().all(|record| record.event
             != RuntimeEvent::EvmSystem(Event::NewAccount {
-                account: PRECOMPILE,
+                account: precompile,
             })));
+
+        // Assert mock invocations.
+        is_precompile_ctx.checkpoint();
     });
 }
 
@@ -254,6 +275,13 @@ fn try_mutate_exists_account_removed() {
         assert!(EvmSystem::account_exists(&account_id));
 
         // Set mock expectations.
+        let is_precompile_ctx = MockPrecompilesSet::is_precompile_context();
+        is_precompile_ctx
+            .expect()
+            .once()
+            .with(predicate::eq(account_id))
+            .return_const(false);
+
         let on_killed_account_ctx = MockDummyOnKilledAccount::on_killed_account_context();
         on_killed_account_ctx
             .expect()
@@ -278,6 +306,7 @@ fn try_mutate_exists_account_removed() {
         }));
 
         // Assert mock invocations.
+        is_precompile_ctx.checkpoint();
         on_killed_account_ctx.checkpoint();
     });
 }
@@ -323,34 +352,46 @@ fn try_mutate_exists_account_retained() {
 fn try_mutate_exists_precompiled_account_retained() {
     new_test_ext().execute_with_ext(|_| {
         // Prepare test data.
+        let precompile = H160::from_str("1000000000000000000000000000000000000001").unwrap();
         let nonce = 0;
         let data = 100;
 
         let account_info = AccountInfo { nonce, data };
-        <Account<Test>>::insert(PRECOMPILE, account_info);
+        <Account<Test>>::insert(precompile, account_info);
 
         // Check test preconditions.
-        assert!(EvmSystem::account_exists(&PRECOMPILE));
+        assert!(EvmSystem::account_exists(&precompile));
+
+        // Set mock expectations.
+        let is_precompile_ctx = MockPrecompilesSet::is_precompile_context();
+        is_precompile_ctx
+            .expect()
+            .once()
+            .with(predicate::eq(precompile))
+            .return_const(true);
 
         // Set block number to enable events.
         System::set_block_number(1);
 
         // Invoke the function under test.
-        EvmSystem::try_mutate_exists(&PRECOMPILE, |maybe_data| -> Result<(), DispatchError> {
+        EvmSystem::try_mutate_exists(&precompile, |maybe_data| -> Result<(), DispatchError> {
             *maybe_data = None;
             Ok(())
         })
         .unwrap();
 
         // Assert state changes.
-        assert!(EvmSystem::account_exists(&PRECOMPILE));
-        assert_eq!(<Account<Test>>::get(PRECOMPILE), AccountInfo::default());
+        assert!(EvmSystem::account_exists(&precompile));
+        assert_eq!(<Account<Test>>::get(precompile), AccountInfo::default());
 
         // Assert that there is no a corresponding `KilledAccount` event.
         assert!(System::events().iter().all(|record| record.event
             != RuntimeEvent::EvmSystem(Event::KilledAccount {
-                account: PRECOMPILE,
+                account: precompile,
             })));
+
+        // Assert mock invocations.
+        is_precompile_ctx.checkpoint();
     });
 }
 

From fc9a6bb428d49b844c5a1e8eca6ee4c273879563 Mon Sep 17 00:00:00 2001
From: Dmitry Lavrenov <lawrenowdima@gmail.com>
Date: Tue, 8 Apr 2025 18:00:07 +0300
Subject: [PATCH 07/15] Some renaming

---
 crates/pallet-evm-system/src/lib.rs   | 14 ++++++--------
 crates/pallet-evm-system/src/mock.rs  |  6 +++---
 crates/pallet-evm-system/src/tests.rs |  8 ++++----
 3 files changed, 13 insertions(+), 15 deletions(-)

diff --git a/crates/pallet-evm-system/src/lib.rs b/crates/pallet-evm-system/src/lib.rs
index f48ceb4fc..baf4fa48c 100644
--- a/crates/pallet-evm-system/src/lib.rs
+++ b/crates/pallet-evm-system/src/lib.rs
@@ -27,10 +27,8 @@ pub struct AccountInfo<Index, AccountData> {
     pub data: AccountData,
 }
 
-/// A set of precompiles.
-///
-/// Checks if the provided account is in the precompile set.
-pub trait PrecompilesSet<AccountId> {
+/// A trait that allows checking whether a given account is a precompile or not.
+pub trait IsPrecompile<AccountId> {
     /// Check if the given account is a precompile.
     fn is_precompile(account_id: &AccountId) -> bool;
 }
@@ -80,8 +78,8 @@ pub mod pallet {
         /// pallet does regardless).
         type AccountData: Member + FullCodec + Clone + Default + TypeInfo + MaxEncodedLen;
 
-        /// A set of precompiles.
-        type PrecompilesSet: PrecompilesSet<<Self as Config>::AccountId>;
+        /// Checks whether a given account is a precompile or not.
+        type IsPrecompile: IsPrecompile<<Self as Config>::AccountId>;
 
         /// Handler for when a new account has just been created.
         type OnNewAccount: OnNewAccount<<Self as Config>::AccountId>;
@@ -170,7 +168,7 @@ impl<T: Config> Pallet<T> {
 
     /// Create an account.
     pub fn create_account(who: &<T as Config>::AccountId) -> AccountCreationOutcome {
-        if Self::account_exists(who) || T::PrecompilesSet::is_precompile(who) {
+        if Self::account_exists(who) || T::IsPrecompile::is_precompile(who) {
             return AccountCreationOutcome::AlreadyExists;
         }
 
@@ -207,7 +205,7 @@ impl<T: Config> StoredMap<<T as Config>::AccountId, <T as Config>::AccountData>
                 Account::<T>::mutate(k, |a| a.data = data);
             }
             (None, true) => {
-                if nonce != <T as Config>::Index::zero() || T::PrecompilesSet::is_precompile(k) {
+                if nonce != <T as Config>::Index::zero() || T::IsPrecompile::is_precompile(k) {
                     Account::<T>::mutate(k, |a| a.data = Default::default());
                 } else {
                     Account::<T>::remove(k);
diff --git a/crates/pallet-evm-system/src/mock.rs b/crates/pallet-evm-system/src/mock.rs
index 8df71e0e5..f39ee285b 100644
--- a/crates/pallet-evm-system/src/mock.rs
+++ b/crates/pallet-evm-system/src/mock.rs
@@ -71,9 +71,9 @@ impl frame_system::Config for Test {
 
 mock! {
     #[derive(Debug)]
-    pub PrecompilesSet {}
+    pub IsPrecompile {}
 
-    impl PrecompilesSet<H160> for PrecompilesSet {
+    impl IsPrecompile<H160> for IsPrecompile {
         pub fn is_precompile(who: &H160) -> bool;
     }
 }
@@ -83,7 +83,7 @@ impl pallet_evm_system::Config for Test {
     type AccountId = H160;
     type Index = u64;
     type AccountData = u64;
-    type PrecompilesSet = MockPrecompilesSet;
+    type IsPrecompile = MockIsPrecompile;
     type OnNewAccount = MockDummyOnNewAccount;
     type OnKilledAccount = MockDummyOnKilledAccount;
 }
diff --git a/crates/pallet-evm-system/src/tests.rs b/crates/pallet-evm-system/src/tests.rs
index c6a014796..611fbd306 100644
--- a/crates/pallet-evm-system/src/tests.rs
+++ b/crates/pallet-evm-system/src/tests.rs
@@ -22,7 +22,7 @@ fn create_account_created() {
         System::set_block_number(1);
 
         // Set mock expectations.
-        let is_precompile_ctx = MockPrecompilesSet::is_precompile_context();
+        let is_precompile_ctx = MockIsPrecompile::is_precompile_context();
         is_precompile_ctx
             .expect()
             .once()
@@ -82,7 +82,7 @@ fn create_precompiled_account_already_exists() {
         let precompile = H160::from_str("1000000000000000000000000000000000000001").unwrap();
 
         // Set mock expectations.
-        let is_precompile_ctx = MockPrecompilesSet::is_precompile_context();
+        let is_precompile_ctx = MockIsPrecompile::is_precompile_context();
         is_precompile_ctx
             .expect()
             .once()
@@ -275,7 +275,7 @@ fn try_mutate_exists_account_removed() {
         assert!(EvmSystem::account_exists(&account_id));
 
         // Set mock expectations.
-        let is_precompile_ctx = MockPrecompilesSet::is_precompile_context();
+        let is_precompile_ctx = MockIsPrecompile::is_precompile_context();
         is_precompile_ctx
             .expect()
             .once()
@@ -363,7 +363,7 @@ fn try_mutate_exists_precompiled_account_retained() {
         assert!(EvmSystem::account_exists(&precompile));
 
         // Set mock expectations.
-        let is_precompile_ctx = MockPrecompilesSet::is_precompile_context();
+        let is_precompile_ctx = MockIsPrecompile::is_precompile_context();
         is_precompile_ctx
             .expect()
             .once()

From e2dbef28aaa97b35011e2506c6ea17b30463d246 Mon Sep 17 00:00:00 2001
From: Dmitry Lavrenov <lawrenowdima@gmail.com>
Date: Tue, 8 Apr 2025 18:01:15 +0300
Subject: [PATCH 08/15] Remove unused deps

---
 Cargo.lock                          | 1 -
 crates/pallet-evm-system/Cargo.toml | 1 -
 2 files changed, 2 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 0a6b1d73b..f453a2ca1 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -6174,7 +6174,6 @@ dependencies = [
  "fp-evm",
  "frame-support",
  "frame-system",
- "hex-literal",
  "mockall",
  "parity-scale-codec",
  "scale-info",
diff --git a/crates/pallet-evm-system/Cargo.toml b/crates/pallet-evm-system/Cargo.toml
index 5f3cbaa05..2e00f444f 100644
--- a/crates/pallet-evm-system/Cargo.toml
+++ b/crates/pallet-evm-system/Cargo.toml
@@ -14,7 +14,6 @@ sp-runtime = { workspace = true }
 sp-std = { workspace = true }
 
 [dev-dependencies]
-hex-literal = { workspace = true }
 mockall = { workspace = true }
 sp-core = { workspace = true }
 sp-io = { workspace = true }

From 68a3d932c0b36cb8dd15e8b0bd143b3e2bddcc76 Mon Sep 17 00:00:00 2001
From: Dmitry Lavrenov <lawrenowdima@gmail.com>
Date: Wed, 9 Apr 2025 18:11:57 +0300
Subject: [PATCH 09/15] Add default implementation for IsPrecompile

---
 crates/pallet-evm-system/src/lib.rs           | 18 ++++++++++++------
 crates/precompile-native-currency/src/mock.rs |  1 +
 2 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/crates/pallet-evm-system/src/lib.rs b/crates/pallet-evm-system/src/lib.rs
index baf4fa48c..99cd4066e 100644
--- a/crates/pallet-evm-system/src/lib.rs
+++ b/crates/pallet-evm-system/src/lib.rs
@@ -27,12 +27,6 @@ pub struct AccountInfo<Index, AccountData> {
     pub data: AccountData,
 }
 
-/// A trait that allows checking whether a given account is a precompile or not.
-pub trait IsPrecompile<AccountId> {
-    /// Check if the given account is a precompile.
-    fn is_precompile(account_id: &AccountId) -> bool;
-}
-
 // We have to temporarily allow some clippy lints. Later on we'll send patches to substrate to
 // fix them at their end.
 #[allow(clippy::missing_docs_in_private_items)]
@@ -242,6 +236,18 @@ impl<T: Config> fp_evm::AccountProvider for Pallet<T> {
     }
 }
 
+/// A trait that allows checking whether a given account is a precompile or not.
+pub trait IsPrecompile<AccountId> {
+    /// Check if the given account is a precompile.
+    fn is_precompile(account_id: &AccountId) -> bool;
+}
+
+impl<AccountId> IsPrecompile<AccountId> for () {
+    fn is_precompile(_account_id: &AccountId) -> bool {
+        false
+    }
+}
+
 /// Interface to handle account creation.
 pub trait OnNewAccount<AccountId> {
     /// A new account `who` has been registered.
diff --git a/crates/precompile-native-currency/src/mock.rs b/crates/precompile-native-currency/src/mock.rs
index 103556e00..37548bfd7 100644
--- a/crates/precompile-native-currency/src/mock.rs
+++ b/crates/precompile-native-currency/src/mock.rs
@@ -104,6 +104,7 @@ impl pallet_evm_system::Config for Test {
     type AccountId = EvmAccountId;
     type Index = u64;
     type AccountData = pallet_evm_balances::AccountData<Balance>;
+    type IsPrecompile = ();
     type OnNewAccount = ();
     type OnKilledAccount = ();
 }

From 03c235e8ebfc0a5b37866b6d329de62f57a7657a Mon Sep 17 00:00:00 2001
From: Dmitry Lavrenov <lawrenowdima@gmail.com>
Date: Wed, 9 Apr 2025 18:14:47 +0300
Subject: [PATCH 10/15] Fix mock for other pallets

---
 crates/pallet-currency-swap/src/mock.rs             | 1 +
 crates/pallet-dummy-precompiles-code/src/mock/v0.rs | 1 +
 crates/pallet-dummy-precompiles-code/src/mock/v1.rs | 1 +
 crates/pallet-evm-balances/src/mock.rs              | 1 +
 crates/pallet-native-to-evm-swap/src/mock.rs        | 1 +
 crates/precompile-evm-to-native-swap/src/mock.rs    | 1 +
 6 files changed, 6 insertions(+)

diff --git a/crates/pallet-currency-swap/src/mock.rs b/crates/pallet-currency-swap/src/mock.rs
index e76cf0a2e..8b09e2e64 100644
--- a/crates/pallet-currency-swap/src/mock.rs
+++ b/crates/pallet-currency-swap/src/mock.rs
@@ -89,6 +89,7 @@ impl pallet_evm_system::Config for Test {
     type AccountId = EvmAccountId;
     type Index = u64;
     type AccountData = pallet_evm_balances::AccountData<Balance>;
+    type IsPrecompile = ();
     type OnNewAccount = ();
     type OnKilledAccount = ();
 }
diff --git a/crates/pallet-dummy-precompiles-code/src/mock/v0.rs b/crates/pallet-dummy-precompiles-code/src/mock/v0.rs
index 7563ef317..73a664f8a 100644
--- a/crates/pallet-dummy-precompiles-code/src/mock/v0.rs
+++ b/crates/pallet-dummy-precompiles-code/src/mock/v0.rs
@@ -94,6 +94,7 @@ impl pallet_evm_system::Config for Test {
     type AccountId = EvmAccountId;
     type Index = u64;
     type AccountData = pallet_evm_balances::AccountData<Balance>;
+    type IsPrecompile = ();
     type OnNewAccount = ();
     type OnKilledAccount = ();
 }
diff --git a/crates/pallet-dummy-precompiles-code/src/mock/v1.rs b/crates/pallet-dummy-precompiles-code/src/mock/v1.rs
index 4f4e069b7..66910e020 100644
--- a/crates/pallet-dummy-precompiles-code/src/mock/v1.rs
+++ b/crates/pallet-dummy-precompiles-code/src/mock/v1.rs
@@ -100,6 +100,7 @@ impl pallet_evm_system::Config for Test {
     type AccountId = EvmAccountId;
     type Index = u64;
     type AccountData = pallet_evm_balances::AccountData<Balance>;
+    type IsPrecompile = ();
     type OnNewAccount = ();
     type OnKilledAccount = ();
 }
diff --git a/crates/pallet-evm-balances/src/mock.rs b/crates/pallet-evm-balances/src/mock.rs
index efe1e8e3f..74b2498cc 100644
--- a/crates/pallet-evm-balances/src/mock.rs
+++ b/crates/pallet-evm-balances/src/mock.rs
@@ -92,6 +92,7 @@ impl pallet_evm_system::Config for Test {
     type AccountId = u64;
     type Index = u64;
     type AccountData = AccountData<u64>;
+    type IsPrecompile = ();
     type OnNewAccount = ();
     type OnKilledAccount = ();
 }
diff --git a/crates/pallet-native-to-evm-swap/src/mock.rs b/crates/pallet-native-to-evm-swap/src/mock.rs
index 2b755dfd7..6cbc7e5a4 100644
--- a/crates/pallet-native-to-evm-swap/src/mock.rs
+++ b/crates/pallet-native-to-evm-swap/src/mock.rs
@@ -100,6 +100,7 @@ impl pallet_evm_system::Config for Test {
     type AccountId = EvmAccountId;
     type Index = u64;
     type AccountData = pallet_evm_balances::AccountData<Balance>;
+    type IsPrecompile = ();
     type OnNewAccount = ();
     type OnKilledAccount = ();
 }
diff --git a/crates/precompile-evm-to-native-swap/src/mock.rs b/crates/precompile-evm-to-native-swap/src/mock.rs
index aaf37c79f..c561fb484 100644
--- a/crates/precompile-evm-to-native-swap/src/mock.rs
+++ b/crates/precompile-evm-to-native-swap/src/mock.rs
@@ -98,6 +98,7 @@ impl pallet_evm_system::Config for Test {
     type AccountId = EvmAccountId;
     type Index = u64;
     type AccountData = pallet_evm_balances::AccountData<Balance>;
+    type IsPrecompile = ();
     type OnNewAccount = ();
     type OnKilledAccount = ();
 }

From ce0a444c5c691deb68d200020f9f97573a61ef9c Mon Sep 17 00:00:00 2001
From: Dmitry Lavrenov <lawrenowdima@gmail.com>
Date: Wed, 9 Apr 2025 18:16:56 +0300
Subject: [PATCH 11/15] Integrate IsPrecompile usage at runtime

---
 crates/humanode-runtime/src/frontier_precompiles.rs | 8 +++++++-
 crates/humanode-runtime/src/lib.rs                  | 1 +
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/crates/humanode-runtime/src/frontier_precompiles.rs b/crates/humanode-runtime/src/frontier_precompiles.rs
index f22f85ba3..1daa3f030 100644
--- a/crates/humanode-runtime/src/frontier_precompiles.rs
+++ b/crates/humanode-runtime/src/frontier_precompiles.rs
@@ -19,7 +19,7 @@ use precompile_utils::EvmData;
 use sp_core::{H160, U256};
 use sp_std::marker::PhantomData;
 
-use crate::{evm_swap, ConstU64};
+use crate::{evm_swap, ConstU64, EvmAccountId};
 
 /// A set of constant values used to indicate precompiles.
 pub mod precompiles_constants {
@@ -187,6 +187,12 @@ where
     }
 }
 
+impl<R> pallet_evm_system::IsPrecompile<EvmAccountId> for FrontierPrecompiles<R> {
+    fn is_precompile(account_id: &EvmAccountId) -> bool {
+        Self::used_addresses().contains(account_id)
+    }
+}
+
 pub struct FrontierPrecompilesAddresses<R>(PhantomData<R>);
 
 impl<R: pallet_evm::Config> sp_core::TypedGet for FrontierPrecompilesAddresses<R> {
diff --git a/crates/humanode-runtime/src/lib.rs b/crates/humanode-runtime/src/lib.rs
index 6e9e561f7..1f64c6413 100644
--- a/crates/humanode-runtime/src/lib.rs
+++ b/crates/humanode-runtime/src/lib.rs
@@ -615,6 +615,7 @@ impl pallet_evm_system::Config for Runtime {
     type AccountId = EvmAccountId;
     type Index = Index;
     type AccountData = pallet_evm_balances::AccountData<Balance>;
+    type IsPrecompile = FrontierPrecompiles<Self>;
     type OnNewAccount = ();
     type OnKilledAccount = ();
 }

From c8bb38157e7c5f9651a194cc4c3d2db8e5c9bcc7 Mon Sep 17 00:00:00 2001
From: Dmitry Lavrenov <lawrenowdima@gmail.com>
Date: Thu, 10 Apr 2025 11:46:32 +0300
Subject: [PATCH 12/15] Prevent remove for precompile

---
 crates/pallet-evm-system/src/lib.rs   |  2 +-
 crates/pallet-evm-system/src/tests.rs | 42 ---------------------------
 2 files changed, 1 insertion(+), 43 deletions(-)

diff --git a/crates/pallet-evm-system/src/lib.rs b/crates/pallet-evm-system/src/lib.rs
index 99cd4066e..f0ef06cfb 100644
--- a/crates/pallet-evm-system/src/lib.rs
+++ b/crates/pallet-evm-system/src/lib.rs
@@ -162,7 +162,7 @@ impl<T: Config> Pallet<T> {
 
     /// Create an account.
     pub fn create_account(who: &<T as Config>::AccountId) -> AccountCreationOutcome {
-        if Self::account_exists(who) || T::IsPrecompile::is_precompile(who) {
+        if Self::account_exists(who) {
             return AccountCreationOutcome::AlreadyExists;
         }
 
diff --git a/crates/pallet-evm-system/src/tests.rs b/crates/pallet-evm-system/src/tests.rs
index 611fbd306..f9e378a78 100644
--- a/crates/pallet-evm-system/src/tests.rs
+++ b/crates/pallet-evm-system/src/tests.rs
@@ -22,13 +22,6 @@ fn create_account_created() {
         System::set_block_number(1);
 
         // Set mock expectations.
-        let is_precompile_ctx = MockIsPrecompile::is_precompile_context();
-        is_precompile_ctx
-            .expect()
-            .once()
-            .with(predicate::eq(account_id))
-            .return_const(false);
-
         let on_new_account_ctx = MockDummyOnNewAccount::on_new_account_context();
         on_new_account_ctx
             .expect()
@@ -53,7 +46,6 @@ fn create_account_created() {
         }));
 
         // Assert mock invocations.
-        is_precompile_ctx.checkpoint();
         on_new_account_ctx.checkpoint();
     });
 }
@@ -75,40 +67,6 @@ fn create_account_already_exists() {
     });
 }
 
-/// This test verifies that trying creating an precompiled account works as expected.
-#[test]
-fn create_precompiled_account_already_exists() {
-    new_test_ext().execute_with_ext(|_| {
-        let precompile = H160::from_str("1000000000000000000000000000000000000001").unwrap();
-
-        // Set mock expectations.
-        let is_precompile_ctx = MockIsPrecompile::is_precompile_context();
-        is_precompile_ctx
-            .expect()
-            .once()
-            .with(predicate::eq(precompile))
-            .return_const(true);
-
-        // Set block number to enable events.
-        System::set_block_number(1);
-
-        // Invoke the function under test.
-        assert_storage_noop!(assert_eq!(
-            EvmSystem::create_account(&precompile),
-            AccountCreationOutcome::AlreadyExists
-        ));
-
-        // Assert that there is no a corresponding `NewAccount` event.
-        assert!(System::events().iter().all(|record| record.event
-            != RuntimeEvent::EvmSystem(Event::NewAccount {
-                account: precompile,
-            })));
-
-        // Assert mock invocations.
-        is_precompile_ctx.checkpoint();
-    });
-}
-
 /// This test verifies that incrementing account nonce works in the happy path
 /// in case a new account should be created.
 #[test]

From 14ed75803a0a1a2047bc203fc5267ada46f9bdd9 Mon Sep 17 00:00:00 2001
From: Dmitry Lavrenov <lawrenowdima@gmail.com>
Date: Thu, 10 Apr 2025 13:24:27 +0300
Subject: [PATCH 13/15] Add events checks at evmToNative e2e test

---
 utils/e2e-tests/ts/tests/swap/evmToNative.ts | 36 ++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/utils/e2e-tests/ts/tests/swap/evmToNative.ts b/utils/e2e-tests/ts/tests/swap/evmToNative.ts
index 9c5abeff4..429bddde8 100644
--- a/utils/e2e-tests/ts/tests/swap/evmToNative.ts
+++ b/utils/e2e-tests/ts/tests/swap/evmToNative.ts
@@ -7,6 +7,7 @@ import evmSwap from "../../lib/abis/evmSwap";
 import { decodeEventLog } from "viem";
 import * as substrate from "../../lib/substrate";
 import { getNativeBalance } from "../../lib/substrateUtils";
+import { AnyJson } from "@polkadot/types-codec/types";
 
 const evmToNativeSwapPrecompileAddress =
   "0x0000000000000000000000000000000000000900";
@@ -16,6 +17,14 @@ const bridgePotNativeAccount =
 const feesPotNativeAccount =
   "hmpwhPbL5XJTYPWXPMkacfqGhJ3eoQRPLKphajpvcot5Q5zkk";
 
+type Event = {
+  event: {
+    method: string;
+    section: string;
+    data: AnyJson;
+  };
+};
+
 describe("evm to native tokens swap", () => {
   let node: RunNodeState;
   let ethPublicClient: eth.PublicClientWebSocket;
@@ -136,5 +145,32 @@ describe("evm to native tokens swap", () => {
       address: evmToNativeSwapPrecompileAddress,
     });
     expect(evmSwapPrecompileBalance).toEqual(0n);
+
+    const blockNumber = swapTxReceipt.blockNumber;
+    const blockHash = await substrateApi.rpc.chain.getBlockHash(blockNumber);
+    const substrateApiAt = await substrateApi.at(blockHash);
+    const events = (await substrateApiAt.query["system"]?.[
+      "events"
+    ]?.()) as unknown as Event[];
+
+    events.forEach((item) => {
+      const section = item.event.section;
+      const method = item.event.method;
+      const data = JSON.stringify(item.event.data);
+
+      console.log(section);
+      console.log(method);
+      console.log(data);
+      expect([section, method, data]).not.toEqual([
+        "evmSystem",
+        "NewAccount",
+        JSON.stringify([evmToNativeSwapPrecompileAddress]),
+      ]);
+      expect([section, method, data]).not.toEqual([
+        "evmSystem",
+        "KilledAccount",
+        JSON.stringify([evmToNativeSwapPrecompileAddress]),
+      ]);
+    });
   });
 });

From 08b20508ac907e6380cadc6a214af9e9362b5685 Mon Sep 17 00:00:00 2001
From: Dmitry Lavrenov <lawrenowdima@gmail.com>
Date: Thu, 10 Apr 2025 13:29:03 +0300
Subject: [PATCH 14/15] Move a helper function for getting events to
 substrateUtils

---
 utils/e2e-tests/ts/lib/substrateUtils.ts     | 23 ++++++++++++++++++++
 utils/e2e-tests/ts/tests/swap/evmToNative.ts | 21 ++----------------
 2 files changed, 25 insertions(+), 19 deletions(-)

diff --git a/utils/e2e-tests/ts/lib/substrateUtils.ts b/utils/e2e-tests/ts/lib/substrateUtils.ts
index dc902396b..a6fcda382 100644
--- a/utils/e2e-tests/ts/lib/substrateUtils.ts
+++ b/utils/e2e-tests/ts/lib/substrateUtils.ts
@@ -1,6 +1,7 @@
 //! Common substrate utils.
 
 import * as substrate from "../lib/substrate";
+import { AnyJson } from "@polkadot/types-codec/types";
 
 type SystemAccount = {
   data: {
@@ -22,3 +23,25 @@ export const getNativeBalance = async (
   // We should explicitly convert to native bigint for math operations.
   return BigInt(free);
 };
+
+type Event = {
+  event: {
+    method: string;
+    section: string;
+    data: AnyJson;
+  };
+};
+
+/// A helper function to get events at specified block.
+export const getEvents = async (
+  substrateApi: substrate.Api,
+  blockNumber: bigint,
+) => {
+  const blockHash = await substrateApi.rpc.chain.getBlockHash(blockNumber);
+  const substrateApiAt = await substrateApi.at(blockHash);
+  const events = (await substrateApiAt.query["system"]?.[
+    "events"
+  ]?.()) as unknown as Event[];
+
+  return events;
+};
diff --git a/utils/e2e-tests/ts/tests/swap/evmToNative.ts b/utils/e2e-tests/ts/tests/swap/evmToNative.ts
index 429bddde8..71286569a 100644
--- a/utils/e2e-tests/ts/tests/swap/evmToNative.ts
+++ b/utils/e2e-tests/ts/tests/swap/evmToNative.ts
@@ -6,8 +6,7 @@ import { beforeEachWithCleanup } from "../../lib/lifecycle";
 import evmSwap from "../../lib/abis/evmSwap";
 import { decodeEventLog } from "viem";
 import * as substrate from "../../lib/substrate";
-import { getNativeBalance } from "../../lib/substrateUtils";
-import { AnyJson } from "@polkadot/types-codec/types";
+import { getEvents, getNativeBalance } from "../../lib/substrateUtils";
 
 const evmToNativeSwapPrecompileAddress =
   "0x0000000000000000000000000000000000000900";
@@ -17,14 +16,6 @@ const bridgePotNativeAccount =
 const feesPotNativeAccount =
   "hmpwhPbL5XJTYPWXPMkacfqGhJ3eoQRPLKphajpvcot5Q5zkk";
 
-type Event = {
-  event: {
-    method: string;
-    section: string;
-    data: AnyJson;
-  };
-};
-
 describe("evm to native tokens swap", () => {
   let node: RunNodeState;
   let ethPublicClient: eth.PublicClientWebSocket;
@@ -146,21 +137,13 @@ describe("evm to native tokens swap", () => {
     });
     expect(evmSwapPrecompileBalance).toEqual(0n);
 
-    const blockNumber = swapTxReceipt.blockNumber;
-    const blockHash = await substrateApi.rpc.chain.getBlockHash(blockNumber);
-    const substrateApiAt = await substrateApi.at(blockHash);
-    const events = (await substrateApiAt.query["system"]?.[
-      "events"
-    ]?.()) as unknown as Event[];
+    const events = await getEvents(substrateApi, swapTxReceipt.blockNumber);
 
     events.forEach((item) => {
       const section = item.event.section;
       const method = item.event.method;
       const data = JSON.stringify(item.event.data);
 
-      console.log(section);
-      console.log(method);
-      console.log(data);
       expect([section, method, data]).not.toEqual([
         "evmSystem",
         "NewAccount",

From 15ee1a1df78ab6109a5ed7736599b4b67a2112d8 Mon Sep 17 00:00:00 2001
From: Dmitry Lavrenov <lawrenowdima@gmail.com>
Date: Thu, 10 Apr 2025 16:18:43 +0300
Subject: [PATCH 15/15] Minor improvement

---
 utils/e2e-tests/ts/tests/swap/evmToNative.ts | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/utils/e2e-tests/ts/tests/swap/evmToNative.ts b/utils/e2e-tests/ts/tests/swap/evmToNative.ts
index 71286569a..8927caead 100644
--- a/utils/e2e-tests/ts/tests/swap/evmToNative.ts
+++ b/utils/e2e-tests/ts/tests/swap/evmToNative.ts
@@ -137,9 +137,12 @@ describe("evm to native tokens swap", () => {
     });
     expect(evmSwapPrecompileBalance).toEqual(0n);
 
-    const events = await getEvents(substrateApi, swapTxReceipt.blockNumber);
+    const substrateEvents = await getEvents(
+      substrateApi,
+      swapTxReceipt.blockNumber,
+    );
 
-    events.forEach((item) => {
+    substrateEvents.forEach((item) => {
       const section = item.event.section;
       const method = item.event.method;
       const data = JSON.stringify(item.event.data);