Implement EIP-8246: "Remove SELFDESTRUCT Burn"

This EIP removes the "burn" feature of SELFDESTRUCT. If a contract
tries to burn ETH the balance is preserved.

https://eips.ethereum.org/EIPS/eip-8246

Author: chfast

test/state/host.cpp

@@ -147,10 +147,13 @@ bool Host::selfdestruct(const address& addr, const address& beneficiary) noexcep
         return false;
     }
 
-    // Transfer may happen multiple times per single account as account's balance
-    // can be increased with a call following previous selfdestruct.
-    beneficiary_acc.balance += balance;
-    acc.balance = 0;  // Zero balance if acc is the beneficiary.
+    if (m_rev < EVMC_AMSTERDAM || beneficiary != addr)
+    {
+        // Transfer may happen multiple times per single account as account's balance
+        // can be increased with a call following previous selfdestruct.
+        beneficiary_acc.balance += balance;
+        acc.balance = 0;  // Zero balance if acc is the beneficiary (before EIP-8246)
+    }
 
     // Mark the destruction if not done already.
     if (!acc.destructed)

test/state/state.cpp

@@ -230,9 +230,16 @@ StateDiff State::build_diff(evmc_revision rev) const
     {
         if (m.destructed)
         {
-            // TODO: This must be done even for just_created
-            //   because destructed may pre-date just_created. Add test to evmone (EEST has it).
-            diff.deleted_accounts.emplace_back(addr);
+            if (rev >= EVMC_AMSTERDAM && m.balance != 0)
+            {
+                // Preserve the balance of the self-destructed account, no burn (EIP-8246).
+                diff.modified_accounts.emplace_back(StateDiff::Entry{addr, 0, m.balance});
+            }
+            else
+            {
+                // Delete account. This must be done also for pre-funded just_created account.
+                diff.deleted_accounts.emplace_back(addr);
+            }
             continue;
         }
         if (m.erase_if_empty && rev >= EVMC_SPURIOUS_DRAGON && m.is_empty())

test/unittests/state_transition_selfdestruct_test.cpp

@@ -109,6 +109,69 @@ TEST_F(state_transition, selfdestruct_double_revert)
 TEST_F(state_transition, selfdestruct_initcode)
 {
     tx.data = selfdestruct(0xbe_address);
+
+    expect.post[compute_create_address(tx.sender, tx.nonce)].exists = false;
+    expect.post[0xbe_address].exists = false;
+}
+
+TEST_F(state_transition, selfdestruct_initcode_amsterdam)
+{
+    // A same-tx-created account that self-destructs ending with a zero balance must not be in the
+    // final state (EIP-8246). In this test we use initcode.
+    rev = EVMC_AMSTERDAM;
+    tx.data = selfdestruct(0xbe_address);
+
+    expect.post[compute_create_address(tx.sender, tx.nonce)].exists = false;
+    expect.post[0xbe_address].exists = false;
+}
+
+TEST_F(state_transition, selfdestruct_prefunded)
+{
+    // Although burn is removed in EIP-8246, the deletion of a pre-funded account still happens.
+    rev = EVMC_CANCUN;
+    const auto created = compute_create_address(tx.sender, tx.nonce);
+    pre[created] = {.balance = 1};
+    tx.data = selfdestruct(0xbe_address);  // Transfer to distinct beneficiary.
+
+    expect.post[created].exists = false;    // Removed, despite pre-existing in the state.
+    expect.post[0xbe_address].balance = 1;  // Pre-funded balance delivered to the beneficiary.
+}
+
+
+TEST_F(state_transition, selfdestruct_prefunded_amsterdam)
+{
+    // Although burn is removed in EIP-8246, the deletion of a pre-funded account still happens.
+    rev = EVMC_AMSTERDAM;
+    const auto created = compute_create_address(tx.sender, tx.nonce);
+    pre[created] = {.balance = 1};
+    tx.data = selfdestruct(0xbe_address);  // Transfer to distinct beneficiary.
+
+    expect.post[created].exists = false;    // Removed, despite pre-existing in the state.
+    expect.post[0xbe_address].balance = 1;  // Pre-funded balance delivered to the beneficiary.
+}
+
+TEST_F(state_transition, selfdestruct_prefunded_burn)
+{
+    // Burn pre-funded ETH by self-destruct to self.
+    rev = EVMC_CANCUN;
+    const auto created = compute_create_address(tx.sender, tx.nonce);
+    pre[created] = {.balance = 1};
+    tx.data = selfdestruct(created);
+
+    expect.post[created].exists = false;  // Removed, despite pre-existing in the state.
+}
+
+TEST_F(state_transition, selfdestruct_prefunded_burn_amsterdam)
+{
+    // Although burn is removed in EIP-8246, the deletion of a pre-funded account still happens.
+    rev = EVMC_AMSTERDAM;
+    const auto created = compute_create_address(tx.sender, tx.nonce);
+    pre[created] = {.balance = 1};
+    tx.data = selfdestruct(created);
+
+    expect.post[created].balance = 1;  // Balance preserved.
+    expect.post[created].nonce = 0;
+    expect.post[created].code = {};
 }
 
 TEST_F(state_transition, massdestruct_shanghai)