See https://github.com/extdn/extdn-phpcs/issues/49

Extdn/Samples/Blocks/DeprecatedFormContainerParent.php

@@ -0,0 +1,6 @@
+<?php
+namespace Extdn\Samples\Blocks;
+
+class DeprecatedFormContainerParent extends \Magento\Backend\Block\Widget\Form\Container
+{
+}

Extdn/Samples/Blocks/DeprecatedFormGenericParent.php

@@ -0,0 +1,6 @@
+<?php
+namespace Extdn\Samples\Blocks;
+
+class DeprecatedFormGenericParent extends \Magento\Backend\Block\Widget\Form\Generic
+{
+}

Extdn/Sniffs/Blocks/DeprecatedParentsSniff.php

@@ -0,0 +1,77 @@
+<?php
+/**
+ * Copyright © ExtDN. All rights reserved.
+ */
+
+declare(strict_types=1);
+
+namespace Extdn\Sniffs\Blocks;
+
+use PHP_CodeSniffer\Files\File;
+use PHP_CodeSniffer\Sniffs\Sniff;
+use Extdn\Utils\Reflection;
+use Zend\Server\Reflection\ReflectionClass;
+
+/**
+ * Class DeprecatedParentsSniff
+ *
+ * @package Extdn\Sniffs\Classes\Constructor
+ */
+class DeprecatedParentsSniff implements Sniff
+{
+    /**
+     * @var string
+     */
+    protected $message = 'The ObjectManager should not be injected into the constructor';
+
+    /**
+     * @inheritdoc
+     */
+    public function register()
+    {
+        return [T_CLASS];
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function process(File $phpcsFile, $stackPtr)
+    {
+        $className = Reflection::findClassName($phpcsFile);
+        if (empty($className)) {
+            return false;
+        }
+
+        // Make sure to load the file itself, so that autoloading can be skipped
+        include_once($phpcsFile->getFilename());
+
+        $class = Reflection::getClass($className);
+        $parentClass = $class->getParentClass();
+
+        foreach ($this->getDeprecatedClasses() as $deprecatedClass) {
+            if ($parentClass->getName() !== $deprecatedClass['class']) {
+                continue;
+            }
+
+            $warning = sprintf('Block parent "%s" is deprecated. %s', $deprecatedClass['class'], $deprecatedClass['advice']);
+            $phpcsFile->addWarning($warning, null, 'deprecated-parent');
+        }
+    }
+
+    /**
+     * @return array
+     */
+    private function getDeprecatedClasses(): array
+    {
+        return [
+            [
+                'class' => 'Magento\Backend\Block\Widget\Form\Generic',
+                'advice' => 'Refactor this to a UiComponent.'
+            ],
+            [
+                'class' => 'Magento\Backend\Block\Widget\Grid\Container',
+                'advice' => 'Refactor this to a UiComponent.'
+            ]
+        ];
+    }
+}

Extdn/ruleset.xml

@@ -7,6 +7,8 @@
         <exclude-pattern>*.php</exclude-pattern>
     </rule>
     <rule ref="Extdn.Blocks.SetTemplateInBlock"/>
+    <rule ref="Extdn.Blocks.DeprecatedParents"/>
     <rule ref="Extdn.Classes.StrictTypes"/>
+    <rule ref="Extdn.Classes.ObjectManager"/>
     <rule ref="Extdn.Templates.TemplateObjectManager"/>
 </ruleset>