diff --git a/src/Symfony/Bundle/FrameworkBundle/Console/Descriptor/Descriptor.php b/src/Symfony/Bundle/FrameworkBundle/Console/Descriptor/Descriptor.php
index cbb01dc6cf4b..fb89768bf5f3 100644
--- a/src/Symfony/Bundle/FrameworkBundle/Console/Descriptor/Descriptor.php
+++ b/src/Symfony/Bundle/FrameworkBundle/Console/Descriptor/Descriptor.php
@@ -94,24 +94,12 @@ protected function write(string $content, bool $decorated = false)
         $this->output->write($content, false, $decorated ? OutputInterface::OUTPUT_NORMAL : OutputInterface::OUTPUT_RAW);
     }
 
-    /**
-     * Describes an InputArgument instance.
-     */
     abstract protected function describeRouteCollection(RouteCollection $routes, array $options = []);
 
-    /**
-     * Describes an InputOption instance.
-     */
     abstract protected function describeRoute(Route $route, array $options = []);
 
-    /**
-     * Describes container parameters.
-     */
     abstract protected function describeContainerParameters(ParameterBag $parameters, array $options = []);
 
-    /**
-     * Describes container tags.
-     */
     abstract protected function describeContainerTags(ContainerBuilder $builder, array $options = []);
 
     /**
@@ -132,24 +120,12 @@ abstract protected function describeContainerService($service, array $options =
      */
     abstract protected function describeContainerServices(ContainerBuilder $builder, array $options = []);
 
-    /**
-     * Describes a service definition.
-     */
     abstract protected function describeContainerDefinition(Definition $definition, array $options = []);
 
-    /**
-     * Describes a service alias.
-     */
     abstract protected function describeContainerAlias(Alias $alias, array $options = [], ContainerBuilder $builder = null);
 
-    /**
-     * Describes a container parameter.
-     */
     abstract protected function describeContainerParameter($parameter, array $options = []);
 
-    /**
-     * Describes container environment variables.
-     */
     abstract protected function describeContainerEnvVars(array $envs, array $options = []);
 
     /**
@@ -305,9 +281,6 @@ protected function sortByPriority(array $tag): array
         return $tag;
     }
 
-    /**
-     * Gets class description from a docblock.
-     */
     public static function getClassDescription(string $class, string &$resolvedClass = null): string
     {
         $resolvedClass = $class;
diff --git a/src/Symfony/Bundle/FrameworkBundle/Console/Descriptor/JsonDescriptor.php b/src/Symfony/Bundle/FrameworkBundle/Console/Descriptor/JsonDescriptor.php
index 9d1e97d5f7f2..b9e5bad0f5c5 100644
--- a/src/Symfony/Bundle/FrameworkBundle/Console/Descriptor/JsonDescriptor.php
+++ b/src/Symfony/Bundle/FrameworkBundle/Console/Descriptor/JsonDescriptor.php
@@ -30,9 +30,6 @@
  */
 class JsonDescriptor extends Descriptor
 {
-    /**
-     * {@inheritdoc}
-     */
     protected function describeRouteCollection(RouteCollection $routes, array $options = [])
     {
         $data = [];
@@ -43,25 +40,16 @@ protected function describeRouteCollection(RouteCollection $routes, array $optio
         $this->writeData($data, $options);
     }
 
-    /**
-     * {@inheritdoc}
-     */
     protected function describeRoute(Route $route, array $options = [])
     {
         $this->writeData($this->getRouteData($route), $options);
     }
 
-    /**
-     * {@inheritdoc}
-     */
     protected function describeContainerParameters(ParameterBag $parameters, array $options = [])
     {
         $this->writeData($this->sortParameters($parameters), $options);
     }
 
-    /**
-     * {@inheritdoc}
-     */
     protected function describeContainerTags(ContainerBuilder $builder, array $options = [])
     {
         $showHidden = isset($options['show_hidden']) && $options['show_hidden'];
@@ -77,9 +65,6 @@ protected function describeContainerTags(ContainerBuilder $builder, array $optio
         $this->writeData($data, $options);
     }
 
-    /**
-     * {@inheritdoc}
-     */
     protected function describeContainerService($service, array $options = [], ContainerBuilder $builder = null)
     {
         if (!isset($options['id'])) {
@@ -95,9 +80,6 @@ protected function describeContainerService($service, array $options = [], Conta
         }
     }
 
-    /**
-     * {@inheritdoc}
-     */
     protected function describeContainerServices(ContainerBuilder $builder, array $options = [])
     {
         $serviceIds = isset($options['tag']) && $options['tag']
@@ -131,17 +113,11 @@ protected function describeContainerServices(ContainerBuilder $builder, array $o
         $this->writeData($data, $options);
     }
 
-    /**
-     * {@inheritdoc}
-     */
     protected function describeContainerDefinition(Definition $definition, array $options = [])
     {
         $this->writeData($this->getContainerDefinitionData($definition, isset($options['omit_tags']) && $options['omit_tags'], isset($options['show_arguments']) && $options['show_arguments']), $options);
     }
 
-    /**
-     * {@inheritdoc}
-     */
     protected function describeContainerAlias(Alias $alias, array $options = [], ContainerBuilder $builder = null)
     {
         if (!$builder) {
@@ -156,25 +132,16 @@ protected function describeContainerAlias(Alias $alias, array $options = [], Con
         );
     }
 
-    /**
-     * {@inheritdoc}
-     */
     protected function describeEventDispatcherListeners(EventDispatcherInterface $eventDispatcher, array $options = [])
     {
         $this->writeData($this->getEventDispatcherListenersData($eventDispatcher, \array_key_exists('event', $options) ? $options['event'] : null), $options);
     }
 
-    /**
-     * {@inheritdoc}
-     */
     protected function describeCallable($callable, array $options = [])
     {
         $this->writeData($this->getCallableData($callable), $options);
     }
 
-    /**
-     * {@inheritdoc}
-     */
     protected function describeContainerParameter($parameter, array $options = [])
     {
         $key = isset($options['parameter']) ? $options['parameter'] : '';
@@ -182,17 +149,11 @@ protected function describeContainerParameter($parameter, array $options = [])
         $this->writeData([$key => $parameter], $options);
     }
 
-    /**
-     * {@inheritdoc}
-     */
     protected function describeContainerEnvVars(array $envs, array $options = [])
     {
         throw new LogicException('Using the JSON format to debug environment variables is not supported.');
     }
 
-    /**
-     * Writes data as json.
-     */
     private function writeData(array $data, array $options)
     {
         $flags = isset($options['json_encoding']) ? $options['json_encoding'] : 0;
diff --git a/src/Symfony/Bundle/FrameworkBundle/Console/Descriptor/MarkdownDescriptor.php b/src/Symfony/Bundle/FrameworkBundle/Console/Descriptor/MarkdownDescriptor.php
index ab4f0567b76a..a04402796b4c 100644
--- a/src/Symfony/Bundle/FrameworkBundle/Console/Descriptor/MarkdownDescriptor.php
+++ b/src/Symfony/Bundle/FrameworkBundle/Console/Descriptor/MarkdownDescriptor.php
@@ -28,9 +28,6 @@
  */
 class MarkdownDescriptor extends Descriptor
 {
-    /**
-     * {@inheritdoc}
-     */
     protected function describeRouteCollection(RouteCollection $routes, array $options = [])
     {
         $first = true;
@@ -45,9 +42,6 @@ protected function describeRouteCollection(RouteCollection $routes, array $optio
         $this->write("\n");
     }
 
-    /**
-     * {@inheritdoc}
-     */
     protected function describeRoute(Route $route, array $options = [])
     {
         $output = '- Path: '.$route->getPath()
@@ -71,9 +65,6 @@ protected function describeRoute(Route $route, array $options = [])
         $this->write("\n");
     }
 
-    /**
-     * {@inheritdoc}
-     */
     protected function describeContainerParameters(ParameterBag $parameters, array $options = [])
     {
         $this->write("Container parameters\n====================\n");
@@ -82,9 +73,6 @@ protected function describeContainerParameters(ParameterBag $parameters, array $
         }
     }
 
-    /**
-     * {@inheritdoc}
-     */
     protected function describeContainerTags(ContainerBuilder $builder, array $options = [])
     {
         $showHidden = isset($options['show_hidden']) && $options['show_hidden'];
@@ -99,9 +87,6 @@ protected function describeContainerTags(ContainerBuilder $builder, array $optio
         }
     }
 
-    /**
-     * {@inheritdoc}
-     */
     protected function describeContainerService($service, array $options = [], ContainerBuilder $builder = null)
     {
         if (!isset($options['id'])) {
@@ -119,9 +104,6 @@ protected function describeContainerService($service, array $options = [], Conta
         }
     }
 
-    /**
-     * {@inheritdoc}
-     */
     protected function describeContainerServices(ContainerBuilder $builder, array $options = [])
     {
         $showHidden = isset($options['show_hidden']) && $options['show_hidden'];
@@ -183,9 +165,6 @@ protected function describeContainerServices(ContainerBuilder $builder, array $o
         }
     }
 
-    /**
-     * {@inheritdoc}
-     */
     protected function describeContainerDefinition(Definition $definition, array $options = [])
     {
         $output = '';
@@ -246,9 +225,6 @@ protected function describeContainerDefinition(Definition $definition, array $op
         $this->write(isset($options['id']) ? sprintf("### %s\n\n%s\n", $options['id'], $output) : $output);
     }
 
-    /**
-     * {@inheritdoc}
-     */
     protected function describeContainerAlias(Alias $alias, array $options = [], ContainerBuilder $builder = null)
     {
         $output = '- Service: `'.$alias.'`'
@@ -270,25 +246,16 @@ protected function describeContainerAlias(Alias $alias, array $options = [], Con
         $this->describeContainerDefinition($builder->getDefinition((string) $alias), array_merge($options, ['id' => (string) $alias]));
     }
 
-    /**
-     * {@inheritdoc}
-     */
     protected function describeContainerParameter($parameter, array $options = [])
     {
         $this->write(isset($options['parameter']) ? sprintf("%s\n%s\n\n%s", $options['parameter'], str_repeat('=', \strlen($options['parameter'])), $this->formatParameter($parameter)) : $parameter);
     }
 
-    /**
-     * {@inheritdoc}
-     */
     protected function describeContainerEnvVars(array $envs, array $options = [])
     {
         throw new LogicException('Using the markdown format to debug environment variables is not supported.');
     }
 
-    /**
-     * {@inheritdoc}
-     */
     protected function describeEventDispatcherListeners(EventDispatcherInterface $eventDispatcher, array $options = [])
     {
         $event = \array_key_exists('event', $options) ? $options['event'] : null;
@@ -322,9 +289,6 @@ protected function describeEventDispatcherListeners(EventDispatcherInterface $ev
         }
     }
 
-    /**
-     * {@inheritdoc}
-     */
     protected function describeCallable($callable, array $options = [])
     {
         $string = '';
diff --git a/src/Symfony/Bundle/FrameworkBundle/Console/Descriptor/TextDescriptor.php b/src/Symfony/Bundle/FrameworkBundle/Console/Descriptor/TextDescriptor.php
index 37e2117bc6cd..45c995a46737 100644
--- a/src/Symfony/Bundle/FrameworkBundle/Console/Descriptor/TextDescriptor.php
+++ b/src/Symfony/Bundle/FrameworkBundle/Console/Descriptor/TextDescriptor.php
@@ -43,9 +43,6 @@ public function __construct(FileLinkFormatter $fileLinkFormatter = null)
         $this->fileLinkFormatter = $fileLinkFormatter;
     }
 
-    /**
-     * {@inheritdoc}
-     */
     protected function describeRouteCollection(RouteCollection $routes, array $options = [])
     {
         $showControllers = isset($options['show_controllers']) && $options['show_controllers'];
@@ -83,9 +80,6 @@ protected function describeRouteCollection(RouteCollection $routes, array $optio
         }
     }
 
-    /**
-     * {@inheritdoc}
-     */
     protected function describeRoute(Route $route, array $options = [])
     {
         $tableHeaders = ['Property', 'Value'];
@@ -112,9 +106,6 @@ protected function describeRoute(Route $route, array $options = [])
         $table->render();
     }
 
-    /**
-     * {@inheritdoc}
-     */
     protected function describeContainerParameters(ParameterBag $parameters, array $options = [])
     {
         $tableHeaders = ['Parameter', 'Value'];
@@ -128,9 +119,6 @@ protected function describeContainerParameters(ParameterBag $parameters, array $
         $options['output']->table($tableHeaders, $tableRows);
     }
 
-    /**
-     * {@inheritdoc}
-     */
     protected function describeContainerTags(ContainerBuilder $builder, array $options = [])
     {
         $showHidden = isset($options['show_hidden']) && $options['show_hidden'];
@@ -147,9 +135,6 @@ protected function describeContainerTags(ContainerBuilder $builder, array $optio
         }
     }
 
-    /**
-     * {@inheritdoc}
-     */
     protected function describeContainerService($service, array $options = [], ContainerBuilder $builder = null)
     {
         if (!isset($options['id'])) {
@@ -171,9 +156,6 @@ protected function describeContainerService($service, array $options = [], Conta
         }
     }
 
-    /**
-     * {@inheritdoc}
-     */
     protected function describeContainerServices(ContainerBuilder $builder, array $options = [])
     {
         $showHidden = isset($options['show_hidden']) && $options['show_hidden'];
@@ -263,9 +245,6 @@ protected function describeContainerServices(ContainerBuilder $builder, array $o
         $options['output']->table($tableHeaders, $tableRows);
     }
 
-    /**
-     * {@inheritdoc}
-     */
     protected function describeContainerDefinition(Definition $definition, array $options = [])
     {
         if (isset($options['id'])) {
@@ -374,9 +353,6 @@ protected function describeContainerDefinition(Definition $definition, array $op
         $options['output']->table($tableHeaders, $tableRows);
     }
 
-    /**
-     * {@inheritdoc}
-     */
     protected function describeContainerAlias(Alias $alias, array $options = [], ContainerBuilder $builder = null)
     {
         if ($alias->isPublic()) {
@@ -392,9 +368,6 @@ protected function describeContainerAlias(Alias $alias, array $options = [], Con
         $this->describeContainerDefinition($builder->getDefinition((string) $alias), array_merge($options, ['id' => (string) $alias]));
     }
 
-    /**
-     * {@inheritdoc}
-     */
     protected function describeContainerParameter($parameter, array $options = [])
     {
         $options['output']->table(
@@ -405,9 +378,6 @@ protected function describeContainerParameter($parameter, array $options = [])
         ]);
     }
 
-    /**
-     * {@inheritdoc}
-     */
     protected function describeContainerEnvVars(array $envs, array $options = [])
     {
         $dump = new Dumper($this->output);
@@ -470,9 +440,6 @@ protected function describeContainerEnvVars(array $envs, array $options = [])
         }
     }
 
-    /**
-     * {@inheritdoc}
-     */
     protected function describeEventDispatcherListeners(EventDispatcherInterface $eventDispatcher, array $options = [])
     {
         $event = \array_key_exists('event', $options) ? $options['event'] : null;
@@ -497,9 +464,6 @@ protected function describeEventDispatcherListeners(EventDispatcherInterface $ev
         }
     }
 
-    /**
-     * {@inheritdoc}
-     */
     protected function describeCallable($callable, array $options = [])
     {
         $this->writeText($this->formatCallable($callable), $options);
diff --git a/src/Symfony/Bundle/FrameworkBundle/Console/Descriptor/XmlDescriptor.php b/src/Symfony/Bundle/FrameworkBundle/Console/Descriptor/XmlDescriptor.php
index 16e79f45f4cb..a7f348e76d21 100644
--- a/src/Symfony/Bundle/FrameworkBundle/Console/Descriptor/XmlDescriptor.php
+++ b/src/Symfony/Bundle/FrameworkBundle/Console/Descriptor/XmlDescriptor.php
@@ -31,41 +31,26 @@
  */
 class XmlDescriptor extends Descriptor
 {
-    /**
-     * {@inheritdoc}
-     */
     protected function describeRouteCollection(RouteCollection $routes, array $options = [])
     {
         $this->writeDocument($this->getRouteCollectionDocument($routes));
     }
 
-    /**
-     * {@inheritdoc}
-     */
     protected function describeRoute(Route $route, array $options = [])
     {
         $this->writeDocument($this->getRouteDocument($route, isset($options['name']) ? $options['name'] : null));
     }
 
-    /**
-     * {@inheritdoc}
-     */
     protected function describeContainerParameters(ParameterBag $parameters, array $options = [])
     {
         $this->writeDocument($this->getContainerParametersDocument($parameters));
     }
 
-    /**
-     * {@inheritdoc}
-     */
     protected function describeContainerTags(ContainerBuilder $builder, array $options = [])
     {
         $this->writeDocument($this->getContainerTagsDocument($builder, isset($options['show_hidden']) && $options['show_hidden']));
     }
 
-    /**
-     * {@inheritdoc}
-     */
     protected function describeContainerService($service, array $options = [], ContainerBuilder $builder = null)
     {
         if (!isset($options['id'])) {
@@ -75,25 +60,16 @@ protected function describeContainerService($service, array $options = [], Conta
         $this->writeDocument($this->getContainerServiceDocument($service, $options['id'], $builder, isset($options['show_arguments']) && $options['show_arguments']));
     }
 
-    /**
-     * {@inheritdoc}
-     */
     protected function describeContainerServices(ContainerBuilder $builder, array $options = [])
     {
         $this->writeDocument($this->getContainerServicesDocument($builder, isset($options['tag']) ? $options['tag'] : null, isset($options['show_hidden']) && $options['show_hidden'], isset($options['show_arguments']) && $options['show_arguments'], isset($options['filter']) ? $options['filter'] : null));
     }
 
-    /**
-     * {@inheritdoc}
-     */
     protected function describeContainerDefinition(Definition $definition, array $options = [])
     {
         $this->writeDocument($this->getContainerDefinitionDocument($definition, isset($options['id']) ? $options['id'] : null, isset($options['omit_tags']) && $options['omit_tags'], isset($options['show_arguments']) && $options['show_arguments']));
     }
 
-    /**
-     * {@inheritdoc}
-     */
     protected function describeContainerAlias(Alias $alias, array $options = [], ContainerBuilder $builder = null)
     {
         $dom = new \DOMDocument('1.0', 'UTF-8');
@@ -110,41 +86,26 @@ protected function describeContainerAlias(Alias $alias, array $options = [], Con
         $this->writeDocument($dom);
     }
 
-    /**
-     * {@inheritdoc}
-     */
     protected function describeEventDispatcherListeners(EventDispatcherInterface $eventDispatcher, array $options = [])
     {
         $this->writeDocument($this->getEventDispatcherListenersDocument($eventDispatcher, \array_key_exists('event', $options) ? $options['event'] : null));
     }
 
-    /**
-     * {@inheritdoc}
-     */
     protected function describeCallable($callable, array $options = [])
     {
         $this->writeDocument($this->getCallableDocument($callable));
     }
 
-    /**
-     * {@inheritdoc}
-     */
     protected function describeContainerParameter($parameter, array $options = [])
     {
         $this->writeDocument($this->getContainerParameterDocument($parameter, $options));
     }
 
-    /**
-     * {@inheritdoc}
-     */
     protected function describeContainerEnvVars(array $envs, array $options = [])
     {
         throw new LogicException('Using the XML format to debug environment variables is not supported.');
     }
 
-    /**
-     * Writes DOM document.
-     */
     private function writeDocument(\DOMDocument $dom)
     {
         $dom->formatOutput = true;
diff --git a/src/Symfony/Component/Form/Extension/Core/Type/CheckboxType.php b/src/Symfony/Component/Form/Extension/Core/Type/CheckboxType.php
index 2b29c5ad9bf1..b1605b50dce8 100644
--- a/src/Symfony/Component/Form/Extension/Core/Type/CheckboxType.php
+++ b/src/Symfony/Component/Form/Extension/Core/Type/CheckboxType.php
@@ -33,6 +33,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
         // doing so also calls setDataLocked(true).
         $builder->setData(isset($options['data']) ? $options['data'] : false);
         $builder->addViewTransformer(new BooleanToStringTransformer($options['value'], $options['false_values']));
+        $builder->setAttribute('_false_is_empty', true); // @internal - A boolean flag to treat false as empty, see Form::isEmpty() - Do not rely on it, it will be removed in Symfony 5.1.
     }
 
     /**
diff --git a/src/Symfony/Component/Form/Form.php b/src/Symfony/Component/Form/Form.php
index c4f0413dd350..23e21eacd2b4 100644
--- a/src/Symfony/Component/Form/Form.php
+++ b/src/Symfony/Component/Form/Form.php
@@ -731,7 +731,9 @@ public function isEmpty()
             // arrays, countables
             ((\is_array($this->modelData) || $this->modelData instanceof \Countable) && 0 === \count($this->modelData)) ||
             // traversables that are not countable
-            ($this->modelData instanceof \Traversable && 0 === iterator_count($this->modelData));
+            ($this->modelData instanceof \Traversable && 0 === iterator_count($this->modelData)) ||
+            // @internal - Do not rely on it, it will be removed in Symfony 5.1.
+            (false === $this->modelData && $this->config->getAttribute('_false_is_empty'));
     }
 
     /**
diff --git a/src/Symfony/Component/Form/Tests/Extension/Core/Type/CheckboxTypeTest.php b/src/Symfony/Component/Form/Tests/Extension/Core/Type/CheckboxTypeTest.php
index 265e5e2b09a5..8391805b2266 100644
--- a/src/Symfony/Component/Form/Tests/Extension/Core/Type/CheckboxTypeTest.php
+++ b/src/Symfony/Component/Form/Tests/Extension/Core/Type/CheckboxTypeTest.php
@@ -220,4 +220,13 @@ public function testSubmitNullUsesDefaultEmptyData($emptyData = 'empty', $expect
         $this->assertSame($expectedData, $form->getNormData());
         $this->assertSame($expectedData, $form->getData());
     }
+
+    public function testSubmitNullIsEmpty()
+    {
+        $form = $this->factory->create(static::TESTED_TYPE);
+
+        $form->submit(null);
+
+        $this->assertTrue($form->isEmpty());
+    }
 }
diff --git a/src/Symfony/Component/Form/Tests/Extension/Core/Type/ChoiceTypeTest.php b/src/Symfony/Component/Form/Tests/Extension/Core/Type/ChoiceTypeTest.php
index f417c234af4c..e82ab917c590 100644
--- a/src/Symfony/Component/Form/Tests/Extension/Core/Type/ChoiceTypeTest.php
+++ b/src/Symfony/Component/Form/Tests/Extension/Core/Type/ChoiceTypeTest.php
@@ -2049,4 +2049,45 @@ public function provideTrimCases()
             'Multiple expanded' => [true, true],
         ];
     }
+
+    /**
+     * @dataProvider expandedIsEmptyWhenNoRealChoiceIsSelectedProvider
+     */
+    public function testExpandedIsEmptyWhenNoRealChoiceIsSelected($expected, $submittedData, $multiple, $required, $placeholder)
+    {
+        $options = [
+            'expanded' => true,
+            'choices' => [
+                'foo' => 'bar',
+            ],
+            'multiple' => $multiple,
+            'required' => $required,
+        ];
+
+        if (!$multiple) {
+            $options['placeholder'] = $placeholder;
+        }
+
+        $form = $this->factory->create(static::TESTED_TYPE, null, $options);
+
+        $form->submit($submittedData);
+
+        $this->assertSame($expected, $form->isEmpty());
+    }
+
+    public function expandedIsEmptyWhenNoRealChoiceIsSelectedProvider()
+    {
+        // Some invalid cases are voluntarily not tested:
+        //   - multiple with placeholder
+        //   - required with placeholder
+        return [
+            'Nothing submitted / single / not required / without a placeholder -> should be empty' => [true, null, false, false, null],
+            'Nothing submitted / single / not required / with a placeholder -> should not be empty' => [false, null, false, false, 'ccc'], // It falls back on the placeholder
+            'Nothing submitted / single / required / without a placeholder -> should be empty' => [true, null, false, true, null],
+            'Nothing submitted / single / required / with a placeholder -> should be empty' => [true, null, false, true, 'ccc'],
+            'Nothing submitted / multiple / not required / without a placeholder -> should be empty' => [true, null, true, false, null],
+            'Nothing submitted / multiple / required / without a placeholder -> should be empty' => [true, null, true, true, null],
+            'Placeholder submitted / single / not required / with a placeholder -> should not be empty' => [false, '', false, false, 'ccc'], // The placeholder is a selected value
+        ];
+    }
 }