diff --git a/sdk/lib/_internal/vm/lib/compact_hash.dart b/sdk/lib/_internal/vm/lib/compact_hash.dart
index 003be2c..8a179fb6 100644
--- a/sdk/lib/_internal/vm/lib/compact_hash.dart
+++ b/sdk/lib/_internal/vm/lib/compact_hash.dart
@@ -695,10 +695,8 @@
   final int _checkSum;
   E? _current;
 
-  _CompactIterator(
-      _HashBase table, this._data, this._len, this._offset, this._step)
-      : _table = table,
-        _checkSum = table._checkSum;
+  _CompactIterator(this._table, this._data, this._len, this._offset, this._step)
+      : _checkSum = _table._checkSum;
 
   bool moveNext() {
     if (_table._isModifiedSince(_data, _checkSum)) {
@@ -720,7 +718,9 @@
 }
 
 // Iterates through _data[_offset + _step], _data[_offset + 2*_step], ...
-// and checks for concurrent modification.
+//
+// Does not check for concurrent modification since the table
+// is known to be immutable.
 class _CompactIterableImmutable<E> extends Iterable<E> {
   // _HashBase with _HashVMImmutableBase.
   final _HashBase _table;
@@ -749,13 +749,10 @@
   final int _len;
   int _offset;
   final int _step;
-  final int _checkSum;
   E? _current;
 
   _CompactIteratorImmutable(
-      _HashBase table, this._data, this._len, this._offset, this._step)
-      : _table = table,
-        _checkSum = table._checkSum;
+      this._table, this._data, this._len, this._offset, this._step);
 
   bool moveNext() {
     _offset += _step;
diff --git a/tools/VERSION b/tools/VERSION
index 7609b64..39885cb 100644
--- a/tools/VERSION
+++ b/tools/VERSION
@@ -27,5 +27,5 @@
 MAJOR 2
 MINOR 18
 PATCH 0
-PRERELEASE 133
+PRERELEASE 134
 PRERELEASE_PATCH 0
\ No newline at end of file