Implement PHPStan up to level 1

phpstan.neon

@@ -0,0 +1,7 @@
+parameters:
+	level: 1
+	ignoreErrors:
+	    -
+	        identifier: new.static
+	paths:
+		- src

src/Connection/ImapConnection.php

@@ -719,7 +719,7 @@ protected function assertTaggedResponse(string $tag, ?callable $exception = null
      *
      * @template T of Response
      *
-     * @param  callable(Response): bool  $filter
+     * @param  callable(T): bool  $filter
      * @return T
      */
     protected function assertNextResponse(callable $filter, callable $assertion, callable $exception): Response
@@ -740,7 +740,7 @@ protected function assertNextResponse(callable $filter, callable $assertion, cal
      *
      * @template T of Response
      *
-     * @param  callable(Response): bool  $filter
+     * @param  callable(T): bool  $filter
      * @return T
      */
     protected function nextResponse(callable $filter): Response

src/Support/ForwardsCalls.php

@@ -33,7 +33,7 @@ protected function forwardCallTo(object $object, string $method, array $paramete
     /**
      * Throw a bad method call exception for the given method.
      */
-    protected static function throwBadMethodCallException(string $method)
+    protected static function throwBadMethodCallException(string $method): never
     {
         throw new BadMethodCallException(sprintf(
             'Call to undefined method %s::%s()', static::class, $method