feat(ctb): standardize spacers (#3470)

Cleans up spacers to all be private, introduces types to the custom
spacer natspec, and renames spacer variables to include slot, offset,
and length so we can automate checks.
Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

.changeset/fifty-rivers-hunt.md

+---
+'@eth-optimism/contracts-bedrock': patch
+---
+
+Makes spacers private and updates names to reflect slot, offset, and length.

op-bindings/bindings/l1crossdomainmessenger_more.go

@@ -9,7 +9,7 @@ import (
 	"github.com/ethereum-optimism/optimism/op-bindings/solc"
 )
 
-const L1CrossDomainMessengerStorageLayoutJSON = "{\"storage\":[{\"astId\":24487,\"contract\":\"contracts/L1/L1CrossDomainMessenger.sol:L1CrossDomainMessenger\",\"label\":\"spacer0\",\"offset\":0,\"slot\":\"0\",\"type\":\"t_address\"},{\"astId\":26933,\"contract\":\"contracts/L1/L1CrossDomainMessenger.sol:L1CrossDomainMessenger\",\"label\":\"_initialized\",\"offset\":20,\"slot\":\"0\",\"type\":\"t_uint8\"},{\"astId\":26936,\"contract\":\"contracts/L1/L1CrossDomainMessenger.sol:L1CrossDomainMessenger\",\"label\":\"_initializing\",\"offset\":21,\"slot\":\"0\",\"type\":\"t_bool\"},{\"astId\":27547,\"contract\":\"contracts/L1/L1CrossDomainMessenger.sol:L1CrossDomainMessenger\",\"label\":\"__gap\",\"offset\":0,\"slot\":\"1\",\"type\":\"t_array(t_uint256)50_storage\"},{\"astId\":26805,\"contract\":\"contracts/L1/L1CrossDomainMessenger.sol:L1CrossDomainMessenger\",\"label\":\"_owner\",\"offset\":0,\"slot\":\"51\",\"type\":\"t_address\"},{\"astId\":26925,\"contract\":\"contracts/L1/L1CrossDomainMessenger.sol:L1CrossDomainMessenger\",\"label\":\"__gap\",\"offset\":0,\"slot\":\"52\",\"type\":\"t_array(t_uint256)49_storage\"},{\"astId\":27098,\"contract\":\"contracts/L1/L1CrossDomainMessenger.sol:L1CrossDomainMessenger\",\"label\":\"_paused\",\"offset\":0,\"slot\":\"101\",\"type\":\"t_bool\"},{\"astId\":27203,\"contract\":\"contracts/L1/L1CrossDomainMessenger.sol:L1CrossDomainMessenger\",\"label\":\"__gap\",\"offset\":0,\"slot\":\"102\",\"type\":\"t_array(t_uint256)49_storage\"},{\"astId\":27218,\"contract\":\"contracts/L1/L1CrossDomainMessenger.sol:L1CrossDomainMessenger\",\"label\":\"_status\",\"offset\":0,\"slot\":\"151\",\"type\":\"t_uint256\"},{\"astId\":27262,\"contract\":\"contracts/L1/L1CrossDomainMessenger.sol:L1CrossDomainMessenger\",\"label\":\"__gap\",\"offset\":0,\"slot\":\"152\",\"type\":\"t_array(t_uint256)49_storage\"},{\"astId\":24537,\"contract\":\"contracts/L1/L1CrossDomainMessenger.sol:L1CrossDomainMessenger\",\"label\":\"spacer1\",\"offset\":0,\"slot\":\"201\",\"type\":\"t_uint256\"},{\"astId\":24540,\"contract\":\"contracts/L1/L1CrossDomainMessenger.sol:L1CrossDomainMessenger\",\"label\":\"spacer2\",\"offset\":0,\"slot\":\"202\",\"type\":\"t_uint256\"},{\"astId\":24545,\"contract\":\"contracts/L1/L1CrossDomainMessenger.sol:L1CrossDomainMessenger\",\"label\":\"successfulMessages\",\"offset\":0,\"slot\":\"203\",\"type\":\"t_mapping(t_bytes32,t_bool)\"},{\"astId\":24548,\"contract\":\"contracts/L1/L1CrossDomainMessenger.sol:L1CrossDomainMessenger\",\"label\":\"xDomainMsgSender\",\"offset\":0,\"slot\":\"204\",\"type\":\"t_address\"},{\"astId\":24551,\"contract\":\"contracts/L1/L1CrossDomainMessenger.sol:L1CrossDomainMessenger\",\"label\":\"msgNonce\",\"offset\":0,\"slot\":\"205\",\"type\":\"t_uint240\"},{\"astId\":24556,\"contract\":\"contracts/L1/L1CrossDomainMessenger.sol:L1CrossDomainMessenger\",\"label\":\"receivedMessages\",\"offset\":0,\"slot\":\"206\",\"type\":\"t_mapping(t_bytes32,t_bool)\"}],\"types\":{\"t_address\":{\"encoding\":\"inplace\",\"label\":\"address\",\"numberOfBytes\":\"20\"},\"t_array(t_uint256)49_storage\":{\"encoding\":\"inplace\",\"label\":\"uint256[49]\",\"numberOfBytes\":\"1568\"},\"t_array(t_uint256)50_storage\":{\"encoding\":\"inplace\",\"label\":\"uint256[50]\",\"numberOfBytes\":\"1600\"},\"t_bool\":{\"encoding\":\"inplace\",\"label\":\"bool\",\"numberOfBytes\":\"1\"},\"t_bytes32\":{\"encoding\":\"inplace\",\"label\":\"bytes32\",\"numberOfBytes\":\"32\"},\"t_mapping(t_bytes32,t_bool)\":{\"encoding\":\"mapping\",\"label\":\"mapping(bytes32 =\u003e bool)\",\"numberOfBytes\":\"32\",\"key\":\"t_bytes32\",\"value\":\"t_bool\"},\"t_uint240\":{\"encoding\":\"inplace\",\"label\":\"uint240\",\"numberOfBytes\":\"30\"},\"t_uint256\":{\"encoding\":\"inplace\",\"label\":\"uint256\",\"numberOfBytes\":\"32\"},\"t_uint8\":{\"encoding\":\"inplace\",\"label\":\"uint8\",\"numberOfBytes\":\"1\"}}}"
+const L1CrossDomainMessengerStorageLayoutJSON = "{\"storage\":[{\"astId\":24487,\"contract\":\"contracts/L1/L1CrossDomainMessenger.sol:L1CrossDomainMessenger\",\"label\":\"spacer_0_0_20\",\"offset\":0,\"slot\":\"0\",\"type\":\"t_bytes20\"},{\"astId\":26933,\"contract\":\"contracts/L1/L1CrossDomainMessenger.sol:L1CrossDomainMessenger\",\"label\":\"_initialized\",\"offset\":20,\"slot\":\"0\",\"type\":\"t_uint8\"},{\"astId\":26936,\"contract\":\"contracts/L1/L1CrossDomainMessenger.sol:L1CrossDomainMessenger\",\"label\":\"_initializing\",\"offset\":21,\"slot\":\"0\",\"type\":\"t_bool\"},{\"astId\":27547,\"contract\":\"contracts/L1/L1CrossDomainMessenger.sol:L1CrossDomainMessenger\",\"label\":\"__gap\",\"offset\":0,\"slot\":\"1\",\"type\":\"t_array(t_uint256)50_storage\"},{\"astId\":26805,\"contract\":\"contracts/L1/L1CrossDomainMessenger.sol:L1CrossDomainMessenger\",\"label\":\"_owner\",\"offset\":0,\"slot\":\"51\",\"type\":\"t_address\"},{\"astId\":26925,\"contract\":\"contracts/L1/L1CrossDomainMessenger.sol:L1CrossDomainMessenger\",\"label\":\"__gap\",\"offset\":0,\"slot\":\"52\",\"type\":\"t_array(t_uint256)49_storage\"},{\"astId\":27098,\"contract\":\"contracts/L1/L1CrossDomainMessenger.sol:L1CrossDomainMessenger\",\"label\":\"_paused\",\"offset\":0,\"slot\":\"101\",\"type\":\"t_bool\"},{\"astId\":27203,\"contract\":\"contracts/L1/L1CrossDomainMessenger.sol:L1CrossDomainMessenger\",\"label\":\"__gap\",\"offset\":0,\"slot\":\"102\",\"type\":\"t_array(t_uint256)49_storage\"},{\"astId\":27218,\"contract\":\"contracts/L1/L1CrossDomainMessenger.sol:L1CrossDomainMessenger\",\"label\":\"_status\",\"offset\":0,\"slot\":\"151\",\"type\":\"t_uint256\"},{\"astId\":27262,\"contract\":\"contracts/L1/L1CrossDomainMessenger.sol:L1CrossDomainMessenger\",\"label\":\"__gap\",\"offset\":0,\"slot\":\"152\",\"type\":\"t_array(t_uint256)49_storage\"},{\"astId\":24537,\"contract\":\"contracts/L1/L1CrossDomainMessenger.sol:L1CrossDomainMessenger\",\"label\":\"spacer_201_0_32\",\"offset\":0,\"slot\":\"201\",\"type\":\"t_bytes32\"},{\"astId\":24540,\"contract\":\"contracts/L1/L1CrossDomainMessenger.sol:L1CrossDomainMessenger\",\"label\":\"spacer_202_0_32\",\"offset\":0,\"slot\":\"202\",\"type\":\"t_bytes32\"},{\"astId\":24545,\"contract\":\"contracts/L1/L1CrossDomainMessenger.sol:L1CrossDomainMessenger\",\"label\":\"successfulMessages\",\"offset\":0,\"slot\":\"203\",\"type\":\"t_mapping(t_bytes32,t_bool)\"},{\"astId\":24548,\"contract\":\"contracts/L1/L1CrossDomainMessenger.sol:L1CrossDomainMessenger\",\"label\":\"xDomainMsgSender\",\"offset\":0,\"slot\":\"204\",\"type\":\"t_address\"},{\"astId\":24551,\"contract\":\"contracts/L1/L1CrossDomainMessenger.sol:L1CrossDomainMessenger\",\"label\":\"msgNonce\",\"offset\":0,\"slot\":\"205\",\"type\":\"t_uint240\"},{\"astId\":24556,\"contract\":\"contracts/L1/L1CrossDomainMessenger.sol:L1CrossDomainMessenger\",\"label\":\"receivedMessages\",\"offset\":0,\"slot\":\"206\",\"type\":\"t_mapping(t_bytes32,t_bool)\"}],\"types\":{\"t_address\":{\"encoding\":\"inplace\",\"label\":\"address\",\"numberOfBytes\":\"20\"},\"t_array(t_uint256)49_storage\":{\"encoding\":\"inplace\",\"label\":\"uint256[49]\",\"numberOfBytes\":\"1568\"},\"t_array(t_uint256)50_storage\":{\"encoding\":\"inplace\",\"label\":\"uint256[50]\",\"numberOfBytes\":\"1600\"},\"t_bool\":{\"encoding\":\"inplace\",\"label\":\"bool\",\"numberOfBytes\":\"1\"},\"t_bytes20\":{\"encoding\":\"inplace\",\"label\":\"bytes20\",\"numberOfBytes\":\"20\"},\"t_bytes32\":{\"encoding\":\"inplace\",\"label\":\"bytes32\",\"numberOfBytes\":\"32\"},\"t_mapping(t_bytes32,t_bool)\":{\"encoding\":\"mapping\",\"label\":\"mapping(bytes32 =\u003e bool)\",\"numberOfBytes\":\"32\",\"key\":\"t_bytes32\",\"value\":\"t_bool\"},\"t_uint240\":{\"encoding\":\"inplace\",\"label\":\"uint240\",\"numberOfBytes\":\"30\"},\"t_uint256\":{\"encoding\":\"inplace\",\"label\":\"uint256\",\"numberOfBytes\":\"32\"},\"t_uint8\":{\"encoding\":\"inplace\",\"label\":\"uint8\",\"numberOfBytes\":\"1\"}}}"
 
 var L1CrossDomainMessengerStorageLayout = new(solc.StorageLayout)
 

op-bindings/bindings/l2crossdomainmessenger_more.go

@@ -9,7 +9,7 @@ import (
 	"github.com/ethereum-optimism/optimism/op-bindings/solc"
 )
 
-const L2CrossDomainMessengerStorageLayoutJSON = "{\"storage\":[{\"astId\":24487,\"contract\":\"contracts/L2/L2CrossDomainMessenger.sol:L2CrossDomainMessenger\",\"label\":\"spacer0\",\"offset\":0,\"slot\":\"0\",\"type\":\"t_address\"},{\"astId\":26933,\"contract\":\"contracts/L2/L2CrossDomainMessenger.sol:L2CrossDomainMessenger\",\"label\":\"_initialized\",\"offset\":20,\"slot\":\"0\",\"type\":\"t_uint8\"},{\"astId\":26936,\"contract\":\"contracts/L2/L2CrossDomainMessenger.sol:L2CrossDomainMessenger\",\"label\":\"_initializing\",\"offset\":21,\"slot\":\"0\",\"type\":\"t_bool\"},{\"astId\":27547,\"contract\":\"contracts/L2/L2CrossDomainMessenger.sol:L2CrossDomainMessenger\",\"label\":\"__gap\",\"offset\":0,\"slot\":\"1\",\"type\":\"t_array(t_uint256)50_storage\"},{\"astId\":26805,\"contract\":\"contracts/L2/L2CrossDomainMessenger.sol:L2CrossDomainMessenger\",\"label\":\"_owner\",\"offset\":0,\"slot\":\"51\",\"type\":\"t_address\"},{\"astId\":26925,\"contract\":\"contracts/L2/L2CrossDomainMessenger.sol:L2CrossDomainMessenger\",\"label\":\"__gap\",\"offset\":0,\"slot\":\"52\",\"type\":\"t_array(t_uint256)49_storage\"},{\"astId\":27098,\"contract\":\"contracts/L2/L2CrossDomainMessenger.sol:L2CrossDomainMessenger\",\"label\":\"_paused\",\"offset\":0,\"slot\":\"101\",\"type\":\"t_bool\"},{\"astId\":27203,\"contract\":\"contracts/L2/L2CrossDomainMessenger.sol:L2CrossDomainMessenger\",\"label\":\"__gap\",\"offset\":0,\"slot\":\"102\",\"type\":\"t_array(t_uint256)49_storage\"},{\"astId\":27218,\"contract\":\"contracts/L2/L2CrossDomainMessenger.sol:L2CrossDomainMessenger\",\"label\":\"_status\",\"offset\":0,\"slot\":\"151\",\"type\":\"t_uint256\"},{\"astId\":27262,\"contract\":\"contracts/L2/L2CrossDomainMessenger.sol:L2CrossDomainMessenger\",\"label\":\"__gap\",\"offset\":0,\"slot\":\"152\",\"type\":\"t_array(t_uint256)49_storage\"},{\"astId\":24537,\"contract\":\"contracts/L2/L2CrossDomainMessenger.sol:L2CrossDomainMessenger\",\"label\":\"spacer1\",\"offset\":0,\"slot\":\"201\",\"type\":\"t_uint256\"},{\"astId\":24540,\"contract\":\"contracts/L2/L2CrossDomainMessenger.sol:L2CrossDomainMessenger\",\"label\":\"spacer2\",\"offset\":0,\"slot\":\"202\",\"type\":\"t_uint256\"},{\"astId\":24545,\"contract\":\"contracts/L2/L2CrossDomainMessenger.sol:L2CrossDomainMessenger\",\"label\":\"successfulMessages\",\"offset\":0,\"slot\":\"203\",\"type\":\"t_mapping(t_bytes32,t_bool)\"},{\"astId\":24548,\"contract\":\"contracts/L2/L2CrossDomainMessenger.sol:L2CrossDomainMessenger\",\"label\":\"xDomainMsgSender\",\"offset\":0,\"slot\":\"204\",\"type\":\"t_address\"},{\"astId\":24551,\"contract\":\"contracts/L2/L2CrossDomainMessenger.sol:L2CrossDomainMessenger\",\"label\":\"msgNonce\",\"offset\":0,\"slot\":\"205\",\"type\":\"t_uint240\"},{\"astId\":24556,\"contract\":\"contracts/L2/L2CrossDomainMessenger.sol:L2CrossDomainMessenger\",\"label\":\"receivedMessages\",\"offset\":0,\"slot\":\"206\",\"type\":\"t_mapping(t_bytes32,t_bool)\"}],\"types\":{\"t_address\":{\"encoding\":\"inplace\",\"label\":\"address\",\"numberOfBytes\":\"20\"},\"t_array(t_uint256)49_storage\":{\"encoding\":\"inplace\",\"label\":\"uint256[49]\",\"numberOfBytes\":\"1568\"},\"t_array(t_uint256)50_storage\":{\"encoding\":\"inplace\",\"label\":\"uint256[50]\",\"numberOfBytes\":\"1600\"},\"t_bool\":{\"encoding\":\"inplace\",\"label\":\"bool\",\"numberOfBytes\":\"1\"},\"t_bytes32\":{\"encoding\":\"inplace\",\"label\":\"bytes32\",\"numberOfBytes\":\"32\"},\"t_mapping(t_bytes32,t_bool)\":{\"encoding\":\"mapping\",\"label\":\"mapping(bytes32 =\u003e bool)\",\"numberOfBytes\":\"32\",\"key\":\"t_bytes32\",\"value\":\"t_bool\"},\"t_uint240\":{\"encoding\":\"inplace\",\"label\":\"uint240\",\"numberOfBytes\":\"30\"},\"t_uint256\":{\"encoding\":\"inplace\",\"label\":\"uint256\",\"numberOfBytes\":\"32\"},\"t_uint8\":{\"encoding\":\"inplace\",\"label\":\"uint8\",\"numberOfBytes\":\"1\"}}}"
+const L2CrossDomainMessengerStorageLayoutJSON = "{\"storage\":[{\"astId\":24487,\"contract\":\"contracts/L2/L2CrossDomainMessenger.sol:L2CrossDomainMessenger\",\"label\":\"spacer_0_0_20\",\"offset\":0,\"slot\":\"0\",\"type\":\"t_bytes20\"},{\"astId\":26933,\"contract\":\"contracts/L2/L2CrossDomainMessenger.sol:L2CrossDomainMessenger\",\"label\":\"_initialized\",\"offset\":20,\"slot\":\"0\",\"type\":\"t_uint8\"},{\"astId\":26936,\"contract\":\"contracts/L2/L2CrossDomainMessenger.sol:L2CrossDomainMessenger\",\"label\":\"_initializing\",\"offset\":21,\"slot\":\"0\",\"type\":\"t_bool\"},{\"astId\":27547,\"contract\":\"contracts/L2/L2CrossDomainMessenger.sol:L2CrossDomainMessenger\",\"label\":\"__gap\",\"offset\":0,\"slot\":\"1\",\"type\":\"t_array(t_uint256)50_storage\"},{\"astId\":26805,\"contract\":\"contracts/L2/L2CrossDomainMessenger.sol:L2CrossDomainMessenger\",\"label\":\"_owner\",\"offset\":0,\"slot\":\"51\",\"type\":\"t_address\"},{\"astId\":26925,\"contract\":\"contracts/L2/L2CrossDomainMessenger.sol:L2CrossDomainMessenger\",\"label\":\"__gap\",\"offset\":0,\"slot\":\"52\",\"type\":\"t_array(t_uint256)49_storage\"},{\"astId\":27098,\"contract\":\"contracts/L2/L2CrossDomainMessenger.sol:L2CrossDomainMessenger\",\"label\":\"_paused\",\"offset\":0,\"slot\":\"101\",\"type\":\"t_bool\"},{\"astId\":27203,\"contract\":\"contracts/L2/L2CrossDomainMessenger.sol:L2CrossDomainMessenger\",\"label\":\"__gap\",\"offset\":0,\"slot\":\"102\",\"type\":\"t_array(t_uint256)49_storage\"},{\"astId\":27218,\"contract\":\"contracts/L2/L2CrossDomainMessenger.sol:L2CrossDomainMessenger\",\"label\":\"_status\",\"offset\":0,\"slot\":\"151\",\"type\":\"t_uint256\"},{\"astId\":27262,\"contract\":\"contracts/L2/L2CrossDomainMessenger.sol:L2CrossDomainMessenger\",\"label\":\"__gap\",\"offset\":0,\"slot\":\"152\",\"type\":\"t_array(t_uint256)49_storage\"},{\"astId\":24537,\"contract\":\"contracts/L2/L2CrossDomainMessenger.sol:L2CrossDomainMessenger\",\"label\":\"spacer_201_0_32\",\"offset\":0,\"slot\":\"201\",\"type\":\"t_bytes32\"},{\"astId\":24540,\"contract\":\"contracts/L2/L2CrossDomainMessenger.sol:L2CrossDomainMessenger\",\"label\":\"spacer_202_0_32\",\"offset\":0,\"slot\":\"202\",\"type\":\"t_bytes32\"},{\"astId\":24545,\"contract\":\"contracts/L2/L2CrossDomainMessenger.sol:L2CrossDomainMessenger\",\"label\":\"successfulMessages\",\"offset\":0,\"slot\":\"203\",\"type\":\"t_mapping(t_bytes32,t_bool)\"},{\"astId\":24548,\"contract\":\"contracts/L2/L2CrossDomainMessenger.sol:L2CrossDomainMessenger\",\"label\":\"xDomainMsgSender\",\"offset\":0,\"slot\":\"204\",\"type\":\"t_address\"},{\"astId\":24551,\"contract\":\"contracts/L2/L2CrossDomainMessenger.sol:L2CrossDomainMessenger\",\"label\":\"msgNonce\",\"offset\":0,\"slot\":\"205\",\"type\":\"t_uint240\"},{\"astId\":24556,\"contract\":\"contracts/L2/L2CrossDomainMessenger.sol:L2CrossDomainMessenger\",\"label\":\"receivedMessages\",\"offset\":0,\"slot\":\"206\",\"type\":\"t_mapping(t_bytes32,t_bool)\"}],\"types\":{\"t_address\":{\"encoding\":\"inplace\",\"label\":\"address\",\"numberOfBytes\":\"20\"},\"t_array(t_uint256)49_storage\":{\"encoding\":\"inplace\",\"label\":\"uint256[49]\",\"numberOfBytes\":\"1568\"},\"t_array(t_uint256)50_storage\":{\"encoding\":\"inplace\",\"label\":\"uint256[50]\",\"numberOfBytes\":\"1600\"},\"t_bool\":{\"encoding\":\"inplace\",\"label\":\"bool\",\"numberOfBytes\":\"1\"},\"t_bytes20\":{\"encoding\":\"inplace\",\"label\":\"bytes20\",\"numberOfBytes\":\"20\"},\"t_bytes32\":{\"encoding\":\"inplace\",\"label\":\"bytes32\",\"numberOfBytes\":\"32\"},\"t_mapping(t_bytes32,t_bool)\":{\"encoding\":\"mapping\",\"label\":\"mapping(bytes32 =\u003e bool)\",\"numberOfBytes\":\"32\",\"key\":\"t_bytes32\",\"value\":\"t_bool\"},\"t_uint240\":{\"encoding\":\"inplace\",\"label\":\"uint240\",\"numberOfBytes\":\"30\"},\"t_uint256\":{\"encoding\":\"inplace\",\"label\":\"uint256\",\"numberOfBytes\":\"32\"},\"t_uint8\":{\"encoding\":\"inplace\",\"label\":\"uint8\",\"numberOfBytes\":\"1\"}}}"
 
 var L2CrossDomainMessengerStorageLayout = new(solc.StorageLayout)
 

op-bindings/bindings/l2standardbridge_more.go

@@ -9,7 +9,7 @@ import (
 	"github.com/ethereum-optimism/optimism/op-bindings/solc"
 )
 
-const L2StandardBridgeStorageLayoutJSON = "{\"storage\":[{\"astId\":26023,\"contract\":\"contracts/L2/L2StandardBridge.sol:L2StandardBridge\",\"label\":\"spacer0\",\"offset\":0,\"slot\":\"0\",\"type\":\"t_uint256\"},{\"astId\":26026,\"contract\":\"contracts/L2/L2StandardBridge.sol:L2StandardBridge\",\"label\":\"spacer1\",\"offset\":0,\"slot\":\"1\",\"type\":\"t_uint256\"},{\"astId\":26033,\"contract\":\"contracts/L2/L2StandardBridge.sol:L2StandardBridge\",\"label\":\"deposits\",\"offset\":0,\"slot\":\"2\",\"type\":\"t_mapping(t_address,t_mapping(t_address,t_uint256))\"}],\"types\":{\"t_address\":{\"encoding\":\"inplace\",\"label\":\"address\",\"numberOfBytes\":\"20\"},\"t_mapping(t_address,t_mapping(t_address,t_uint256))\":{\"encoding\":\"mapping\",\"label\":\"mapping(address =\u003e mapping(address =\u003e uint256))\",\"numberOfBytes\":\"32\",\"key\":\"t_address\",\"value\":\"t_mapping(t_address,t_uint256)\"},\"t_mapping(t_address,t_uint256)\":{\"encoding\":\"mapping\",\"label\":\"mapping(address =\u003e uint256)\",\"numberOfBytes\":\"32\",\"key\":\"t_address\",\"value\":\"t_uint256\"},\"t_uint256\":{\"encoding\":\"inplace\",\"label\":\"uint256\",\"numberOfBytes\":\"32\"}}}"
+const L2StandardBridgeStorageLayoutJSON = "{\"storage\":[{\"astId\":26023,\"contract\":\"contracts/L2/L2StandardBridge.sol:L2StandardBridge\",\"label\":\"spacer_0_0_32\",\"offset\":0,\"slot\":\"0\",\"type\":\"t_bytes32\"},{\"astId\":26026,\"contract\":\"contracts/L2/L2StandardBridge.sol:L2StandardBridge\",\"label\":\"spacer_1_0_32\",\"offset\":0,\"slot\":\"1\",\"type\":\"t_bytes32\"},{\"astId\":26033,\"contract\":\"contracts/L2/L2StandardBridge.sol:L2StandardBridge\",\"label\":\"deposits\",\"offset\":0,\"slot\":\"2\",\"type\":\"t_mapping(t_address,t_mapping(t_address,t_uint256))\"}],\"types\":{\"t_address\":{\"encoding\":\"inplace\",\"label\":\"address\",\"numberOfBytes\":\"20\"},\"t_bytes32\":{\"encoding\":\"inplace\",\"label\":\"bytes32\",\"numberOfBytes\":\"32\"},\"t_mapping(t_address,t_mapping(t_address,t_uint256))\":{\"encoding\":\"mapping\",\"label\":\"mapping(address =\u003e mapping(address =\u003e uint256))\",\"numberOfBytes\":\"32\",\"key\":\"t_address\",\"value\":\"t_mapping(t_address,t_uint256)\"},\"t_mapping(t_address,t_uint256)\":{\"encoding\":\"mapping\",\"label\":\"mapping(address =\u003e uint256)\",\"numberOfBytes\":\"32\",\"key\":\"t_address\",\"value\":\"t_uint256\"},\"t_uint256\":{\"encoding\":\"inplace\",\"label\":\"uint256\",\"numberOfBytes\":\"32\"}}}"
 
 var L2StandardBridgeStorageLayout = new(solc.StorageLayout)
 

packages/contracts-bedrock/.storage-layout

@@ -9,7 +9,7 @@
 +--------------------+--------------------------+------+--------+-------+----------------------------------------------------------------+
 | Name               | Type                     | Slot | Offset | Bytes | Contract                                                       |
 +========================================================================================================================================+
-| spacer0            | address                  | 0    | 0      | 20    | contracts/L1/L1CrossDomainMessenger.sol:L1CrossDomainMessenger |
+| spacer_0_0_20      | bytes20                  | 0    | 0      | 20    | contracts/L1/L1CrossDomainMessenger.sol:L1CrossDomainMessenger |
 |--------------------+--------------------------+------+--------+-------+----------------------------------------------------------------|
 | _initialized       | uint8                    | 0    | 20     | 1     | contracts/L1/L1CrossDomainMessenger.sol:L1CrossDomainMessenger |
 |--------------------+--------------------------+------+--------+-------+----------------------------------------------------------------|
@@ -29,9 +29,9 @@
 |--------------------+--------------------------+------+--------+-------+----------------------------------------------------------------|
 | __gap              | uint256[49]              | 152  | 0      | 1568  | contracts/L1/L1CrossDomainMessenger.sol:L1CrossDomainMessenger |
 |--------------------+--------------------------+------+--------+-------+----------------------------------------------------------------|
-| spacer1            | uint256                  | 201  | 0      | 32    | contracts/L1/L1CrossDomainMessenger.sol:L1CrossDomainMessenger |
+| spacer_201_0_32    | bytes32                  | 201  | 0      | 32    | contracts/L1/L1CrossDomainMessenger.sol:L1CrossDomainMessenger |
 |--------------------+--------------------------+------+--------+-------+----------------------------------------------------------------|
-| spacer2            | uint256                  | 202  | 0      | 32    | contracts/L1/L1CrossDomainMessenger.sol:L1CrossDomainMessenger |
+| spacer_202_0_32    | bytes32                  | 202  | 0      | 32    | contracts/L1/L1CrossDomainMessenger.sol:L1CrossDomainMessenger |
 |--------------------+--------------------------+------+--------+-------+----------------------------------------------------------------|
 | successfulMessages | mapping(bytes32 => bool) | 203  | 0      | 32    | contracts/L1/L1CrossDomainMessenger.sol:L1CrossDomainMessenger |
 |--------------------+--------------------------+------+--------+-------+----------------------------------------------------------------|
@@ -46,15 +46,15 @@
 ➡ contracts/L1/L1StandardBridge.sol:L1StandardBridge
 =======================
 
-+----------+-------------------------------------------------+------+--------+-------+----------------------------------------------------+
++---------------+-------------------------------------------------+------+--------+-------+----------------------------------------------------+
 | Name          | Type                                            | Slot | Offset | Bytes | Contract                                           |
-+=========================================================================================================================================+
-| spacer0  | uint256                                         | 0    | 0      | 32    | contracts/L1/L1StandardBridge.sol:L1StandardBridge |
-|----------+-------------------------------------------------+------+--------+-------+----------------------------------------------------|
-| spacer1  | uint256                                         | 1    | 0      | 32    | contracts/L1/L1StandardBridge.sol:L1StandardBridge |
-|----------+-------------------------------------------------+------+--------+-------+----------------------------------------------------|
++==============================================================================================================================================+
+| spacer_0_0_32 | bytes32                                         | 0    | 0      | 32    | contracts/L1/L1StandardBridge.sol:L1StandardBridge |
+|---------------+-------------------------------------------------+------+--------+-------+----------------------------------------------------|
+| spacer_1_0_32 | bytes32                                         | 1    | 0      | 32    | contracts/L1/L1StandardBridge.sol:L1StandardBridge |
+|---------------+-------------------------------------------------+------+--------+-------+----------------------------------------------------|
 | deposits      | mapping(address => mapping(address => uint256)) | 2    | 0      | 32    | contracts/L1/L1StandardBridge.sol:L1StandardBridge |
-+----------+-------------------------------------------------+------+--------+-------+----------------------------------------------------+
++---------------+-------------------------------------------------+------+--------+-------+----------------------------------------------------+
 
 =======================
 ➡ contracts/L1/L2OutputOracle.sol:L2OutputOracle
@@ -168,7 +168,7 @@
 +--------------------+--------------------------+------+--------+-------+----------------------------------------------------------------+
 | Name               | Type                     | Slot | Offset | Bytes | Contract                                                       |
 +========================================================================================================================================+
-| spacer0            | address                  | 0    | 0      | 20    | contracts/L2/L2CrossDomainMessenger.sol:L2CrossDomainMessenger |
+| spacer_0_0_20      | bytes20                  | 0    | 0      | 20    | contracts/L2/L2CrossDomainMessenger.sol:L2CrossDomainMessenger |
 |--------------------+--------------------------+------+--------+-------+----------------------------------------------------------------|
 | _initialized       | uint8                    | 0    | 20     | 1     | contracts/L2/L2CrossDomainMessenger.sol:L2CrossDomainMessenger |
 |--------------------+--------------------------+------+--------+-------+----------------------------------------------------------------|
@@ -188,9 +188,9 @@
 |--------------------+--------------------------+------+--------+-------+----------------------------------------------------------------|
 | __gap              | uint256[49]              | 152  | 0      | 1568  | contracts/L2/L2CrossDomainMessenger.sol:L2CrossDomainMessenger |
 |--------------------+--------------------------+------+--------+-------+----------------------------------------------------------------|
-| spacer1            | uint256                  | 201  | 0      | 32    | contracts/L2/L2CrossDomainMessenger.sol:L2CrossDomainMessenger |
+| spacer_201_0_32    | bytes32                  | 201  | 0      | 32    | contracts/L2/L2CrossDomainMessenger.sol:L2CrossDomainMessenger |
 |--------------------+--------------------------+------+--------+-------+----------------------------------------------------------------|
-| spacer2            | uint256                  | 202  | 0      | 32    | contracts/L2/L2CrossDomainMessenger.sol:L2CrossDomainMessenger |
+| spacer_202_0_32    | bytes32                  | 202  | 0      | 32    | contracts/L2/L2CrossDomainMessenger.sol:L2CrossDomainMessenger |
 |--------------------+--------------------------+------+--------+-------+----------------------------------------------------------------|
 | successfulMessages | mapping(bytes32 => bool) | 203  | 0      | 32    | contracts/L2/L2CrossDomainMessenger.sol:L2CrossDomainMessenger |
 |--------------------+--------------------------+------+--------+-------+----------------------------------------------------------------|
@@ -205,15 +205,15 @@
 ➡ contracts/L2/L2StandardBridge.sol:L2StandardBridge
 =======================
 
-+----------+-------------------------------------------------+------+--------+-------+----------------------------------------------------+
++---------------+-------------------------------------------------+------+--------+-------+----------------------------------------------------+
 | Name          | Type                                            | Slot | Offset | Bytes | Contract                                           |
-+=========================================================================================================================================+
-| spacer0  | uint256                                         | 0    | 0      | 32    | contracts/L2/L2StandardBridge.sol:L2StandardBridge |
-|----------+-------------------------------------------------+------+--------+-------+----------------------------------------------------|
-| spacer1  | uint256                                         | 1    | 0      | 32    | contracts/L2/L2StandardBridge.sol:L2StandardBridge |
-|----------+-------------------------------------------------+------+--------+-------+----------------------------------------------------|
++==============================================================================================================================================+
+| spacer_0_0_32 | bytes32                                         | 0    | 0      | 32    | contracts/L2/L2StandardBridge.sol:L2StandardBridge |
+|---------------+-------------------------------------------------+------+--------+-------+----------------------------------------------------|
+| spacer_1_0_32 | bytes32                                         | 1    | 0      | 32    | contracts/L2/L2StandardBridge.sol:L2StandardBridge |
+|---------------+-------------------------------------------------+------+--------+-------+----------------------------------------------------|
 | deposits      | mapping(address => mapping(address => uint256)) | 2    | 0      | 32    | contracts/L2/L2StandardBridge.sol:L2StandardBridge |
-+----------+-------------------------------------------------+------+--------+-------+----------------------------------------------------+
++---------------+-------------------------------------------------+------+--------+-------+----------------------------------------------------+
 
 =======================
 ➡ contracts/L2/L2ToL1MessagePasser.sol:L2ToL1MessagePasser

packages/contracts-bedrock/README.md

@@ -118,6 +118,12 @@ We also have the following custom tags:
 
 - Event parameters should NOT be prefixed with an underscore.
 
+#### Spacers
+
+We use spacer variables to account for old storage slots that are no longer being used.
+The name of a spacer variable MUST be in the format `spacer_<slot>_<offset>_<length>` where `<slot>` is the original storage slot number, `<offset>` is the original offset position within the storage slot, and `<length>` is the original size of the variable.
+Spacers MUST be `private`.
+
 ### Proxy by Default
 
 All contracts should be assumed to live behind proxies (except in certain special circumstances).

packages/contracts-bedrock/contracts/universal/CrossDomainMessenger.sol

@@ -24,10 +24,10 @@ import { Encoding } from "../libraries/Encoding.sol";
 contract CrossDomainMessengerLegacySpacer {
     /**
      * @custom:legacy
-     * @custom:spacer libAddressManager
+     * @custom:spacer address libAddressManager
      * @notice Spacer for backwards compatibility.
      */
-    address private spacer0;
+    bytes20 private spacer_0_0_20;
 }
 
 /**
@@ -93,17 +93,17 @@ abstract contract CrossDomainMessenger is
 
     /**
      * @custom:legacy
-     * @custom:spacer blockedMessages
+     * @custom:spacer mapping(bytes32=>bool) blockedMessages
      * @notice Spacer for backwards compatibility.
      */
-    uint256 private spacer1;
+    bytes32 private spacer_201_0_32;
 
     /**
      * @custom:legacy
-     * @custom:spacer relayedMessages
+     * @custom:spacer mapping(bytes32=>bool) relayedMessages
      * @notice Spacer for backwards compatibility.
      */
-    uint256 private spacer2;
+    bytes32 private spacer_202_0_32;
 
     /**
      * @notice Mapping of message hashes to boolean receipt values. Note that a message will only

packages/contracts-bedrock/contracts/universal/StandardBridge.sol

@@ -34,15 +34,17 @@ abstract contract StandardBridge {
 
     /**
      * @custom:legacy
+     * @custom:spacer address messenger
      * @notice Spacer for backwards compatibility.
      */
-    uint256 private spacer0;
+    bytes32 private spacer_0_0_32;
 
     /**
      * @custom:legacy
+     * @custom:spacer address l2TokenBridge
      * @notice Spacer for backwards compatibility.
      */
-    uint256 private spacer1;
+    bytes32 private spacer_1_0_32;
 
     /**
      * @notice Mapping that stores deposits for a given pair of local and remote tokens.