Remove deprecated Connection::TRANSACTION_* constants

UPGRADE.md

@@ -3,6 +3,7 @@
 ## BC BREAK Removed previously deprecated features
 
  * Removed `json_array` type and all associated hacks.
+ * Removed `Connection::TRANSACTION_*` constants.
 
 ## BC BREAK changes the `Driver::connect()` signature
 

src/Connection.php

@@ -40,34 +40,6 @@ use function key;
  */
 class Connection implements DriverConnection
 {
-    /**
-     * Constant for transaction isolation level READ UNCOMMITTED.
-     *
-     * @deprecated Use TransactionIsolationLevel::READ_UNCOMMITTED.
-     */
-    public const TRANSACTION_READ_UNCOMMITTED = TransactionIsolationLevel::READ_UNCOMMITTED;
-
-    /**
-     * Constant for transaction isolation level READ COMMITTED.
-     *
-     * @deprecated Use TransactionIsolationLevel::READ_COMMITTED.
-     */
-    public const TRANSACTION_READ_COMMITTED = TransactionIsolationLevel::READ_COMMITTED;
-
-    /**
-     * Constant for transaction isolation level REPEATABLE READ.
-     *
-     * @deprecated Use TransactionIsolationLevel::REPEATABLE_READ.
-     */
-    public const TRANSACTION_REPEATABLE_READ = TransactionIsolationLevel::REPEATABLE_READ;
-
-    /**
-     * Constant for transaction isolation level SERIALIZABLE.
-     *
-     * @deprecated Use TransactionIsolationLevel::SERIALIZABLE.
-     */
-    public const TRANSACTION_SERIALIZABLE = TransactionIsolationLevel::SERIALIZABLE;
-
     /**
      * Represents an array of ints to be expanded by Doctrine SQL parsing.
      */