Change nonce type back to U256

src/backend/memory.rs

@@ -47,7 +47,7 @@ pub struct MemoryVicinity {
 #[cfg_attr(feature = "with-serde", derive(serde::Serialize, serde::Deserialize))]
 pub struct MemoryAccount {
 	/// Account nonce.
-	pub nonce: u64,
+	pub nonce: U256,
 	/// Account balance.
 	pub balance: U256,
 	/// Full account storage.
@@ -210,7 +210,8 @@ impl<'vicinity> ApplyBackend for MemoryBackend<'vicinity> {
 						}
 
 						account.balance == U256::zero()
-							&& account.nonce == 0 && account.code.is_empty()
+							&& account.nonce == U256::zero()
+							&& account.code.is_empty()
 					};
 
 					if is_empty && delete_empty {

src/backend/mod.rs

@@ -20,7 +20,7 @@ pub struct Basic {
 	/// Account balance.
 	pub balance: U256,
 	/// Account nonce.
-	pub nonce: u64,
+	pub nonce: U256,
 }
 
 pub use ethereum::Log;

src/executor/stack/executor.rs

@@ -618,7 +618,7 @@ impl<'config, 'precompiles, S: StackState<'config>, P: PrecompileSet>
 	}
 
 	/// Get account nonce.
-	pub fn nonce(&self, address: H160) -> u64 {
+	pub fn nonce(&self, address: H160) -> U256 {
 		self.state.basic(address).nonce
 	}
 
@@ -734,7 +734,7 @@ impl<'config, 'precompiles, S: StackState<'config>, P: PrecompileSet>
 				return Capture::Exit((ExitError::CreateCollision.into(), None, Vec::new()));
 			}
 
-			if self.nonce(address) > 0 {
+			if self.nonce(address) > U256::zero() {
 				let _ = self.exit_substate(StackExitKind::Failed);
 				return Capture::Exit((ExitError::CreateCollision.into(), None, Vec::new()));
 			}

src/executor/stack/memory.rs

@@ -198,14 +198,14 @@ impl<'config> MemoryStackSubstate<'config> {
 				return Some(false);
 			}
 
-			if account.basic.nonce != 0 {
+			if account.basic.nonce != U256::zero() {
 				return Some(false);
 			}
 
 			if let Some(code) = &account.code {
 				return Some(
 					account.basic.balance == U256::zero()
-						&& account.basic.nonce == 0
+						&& account.basic.nonce == U256::zero()
 						&& code.is_empty(),
 				);
 			}
@@ -303,7 +303,10 @@ impl<'config> MemoryStackSubstate<'config> {
 
 	pub fn inc_nonce<B: Backend>(&mut self, address: H160, backend: &B) -> Result<(), ExitError> {
 		let nonce = &mut self.account_mut(address, backend).basic.nonce;
-		*nonce = nonce.checked_add(1).ok_or(ExitError::MaxNonce)?;
+		if *nonce >= U256::from(u64::MAX) {
+			return Err(ExitError::MaxNonce);
+		}
+		*nonce += U256::one();
 		Ok(())
 	}
 
@@ -499,7 +502,7 @@ impl<'backend, 'config, B: Backend> StackState<'config> for MemoryStackState<'ba
 		}
 
 		self.backend.basic(address).balance == U256::zero()
-			&& self.backend.basic(address).nonce == 0
+			&& self.backend.basic(address).nonce == U256::zero()
 			&& self.backend.code(address).len() == 0
 	}