Restore library-specific return types

The order of interface declarations is important to avoid a PHP bug validating method prototypes.

src/PostgresConnection.php

@@ -10,7 +10,7 @@
 /**
  * @extends Connection<PostgresConfig, PostgresResult, PostgresStatement, PostgresTransaction>
  */
-interface PostgresConnection extends Connection, PostgresLink
+interface PostgresConnection extends PostgresLink, Connection
 {
     /**
      * @return PostgresConfig Config object specific to this library.

src/PostgresExecutor.php

@@ -9,8 +9,23 @@
 /**
  * @extends Executor<PostgresResult, PostgresStatement>
  */
-interface PostgresExecutor extends Executor, PostgresQuoter
+interface PostgresExecutor extends PostgresQuoter, Executor
 {
+    /**
+     * @return PostgresResult Result object specific to this library.
+     */
+    public function query(string $sql): PostgresResult;
+
+    /**
+     * @return PostgresStatement Statement object specific to this library.
+     */
+    public function prepare(string $sql): PostgresStatement;
+
+    /**
+     * @return PostgresResult Result object specific to this library.
+     */
+    public function execute(string $sql, array $params = []): PostgresResult;
+
     /**
      * @param non-empty-string $channel Channel name.
      * @param string $payload Notification payload.

src/PostgresLink.php

@@ -7,6 +7,10 @@
 /**
  * @extends Link<PostgresResult, PostgresStatement, PostgresTransaction>
  */
-interface PostgresLink extends Link, PostgresExecutor
+interface PostgresLink extends PostgresExecutor, Link
 {
+    /**
+     * @return PostgresTransaction Transaction object specific to this library.
+     */
+    public function beginTransaction(): PostgresTransaction;
 }

src/PostgresTransaction.php

@@ -9,6 +9,6 @@
  *
  * @extends Transaction<PostgresResult, PostgresStatement, PostgresTransaction>
  */
-interface PostgresTransaction extends Transaction, PostgresLink
+interface PostgresTransaction extends PostgresLink, Transaction
 {
 }