diff --git a/core/lib/Drupal/Core/Cache/ApcuBackend.php b/core/lib/Drupal/Core/Cache/ApcuBackend.php
index 9bac79e..f3e0acc 100644
--- a/core/lib/Drupal/Core/Cache/ApcuBackend.php
+++ b/core/lib/Drupal/Core/Cache/ApcuBackend.php
@@ -7,6 +7,8 @@
 
 namespace Drupal\Core\Cache;
 
+use Drupal\Component\Assertion\Inspector;
+
 /**
  * Stores cache items in the Alternative PHP Cache User Cache (APCu).
  */
@@ -166,7 +168,7 @@ protected function prepareItem($cache, $allow_invalid) {
    * {@inheritdoc}
    */
   public function set($cid, $data, $expire = CacheBackendInterface::CACHE_PERMANENT, array $tags = array()) {
-    Cache::validateTags($tags);
+    assert(Inspector::assertAllStrings($tags), 'Cache Tags must be strings.');
     $tags = array_unique($tags);
     $cache = new \stdClass();
     $cache->cid = $cid;
diff --git a/core/lib/Drupal/Core/Cache/Cache.php b/core/lib/Drupal/Core/Cache/Cache.php
index 5ad9500..0c66244 100644
--- a/core/lib/Drupal/Core/Cache/Cache.php
+++ b/core/lib/Drupal/Core/Cache/Cache.php
@@ -7,6 +7,7 @@
 
 namespace Drupal\Core\Cache;
 
+use Drupal\Component\Assertion\Inspector;
 use Drupal\Core\Database\Query\SelectInterface;
 
 /**
@@ -59,8 +60,9 @@ public static function mergeContexts(array $a = [], array $b = []) {
    *   The merged array of cache tags.
    */
   public static function mergeTags(array $a = [], array $b = []) {
+    assert(Inspector::assertAllStrings($a) && Inspector::assertAllStrings($b));
+
     $cache_tags = array_unique(array_merge($a, $b));
-    static::validateTags($cache_tags);
     sort($cache_tags);
     return $cache_tags;
   }
@@ -99,6 +101,9 @@ public static function mergeMaxAges($a = Cache::PERMANENT, $b = Cache::PERMANENT
    * @param string[] $tags
    *   An array of cache tags.
    *
+   * @deprecated
+   *   Use assert(\Drupal\Component\Assertion\Inspector::assertAllStrings($tags));
+   *
    * @throws \LogicException
    */
   public static function validateTags(array $tags) {
diff --git a/core/lib/Drupal/Core/Cache/CacheCollector.php b/core/lib/Drupal/Core/Cache/CacheCollector.php
index a6d8ab5..d387a12 100644
--- a/core/lib/Drupal/Core/Cache/CacheCollector.php
+++ b/core/lib/Drupal/Core/Cache/CacheCollector.php
@@ -7,6 +7,7 @@
 
 namespace Drupal\Core\Cache;
 
+use Drupal\Component\Assertion\Inspector;
 use Drupal\Core\DestructableInterface;
 use Drupal\Core\Lock\LockBackendInterface;
 
@@ -115,7 +116,7 @@
    *   (optional) The tags to specify for the cache item.
    */
   public function __construct($cid, CacheBackendInterface $cache, LockBackendInterface $lock, array $tags = array()) {
-    Cache::validateTags($tags);
+    assert(Inspector::assertAllStrings($tags), 'Cache Tags must be strings.');
     $this->cid = $cid;
     $this->cache = $cache;
     $this->tags = $tags;
diff --git a/core/lib/Drupal/Core/Cache/CacheTagsInvalidator.php b/core/lib/Drupal/Core/Cache/CacheTagsInvalidator.php
index 64a8eb0..c798071 100644
--- a/core/lib/Drupal/Core/Cache/CacheTagsInvalidator.php
+++ b/core/lib/Drupal/Core/Cache/CacheTagsInvalidator.php
@@ -7,6 +7,7 @@
 
 namespace Drupal\Core\Cache;
 
+use Drupal\Component\Assertion\Inspector;
 use Symfony\Component\DependencyInjection\ContainerAwareTrait;
 
 /**
@@ -28,7 +29,7 @@ class CacheTagsInvalidator implements CacheTagsInvalidatorInterface {
    */
   public function invalidateTags(array $tags) {
     // Validate the tags.
-    Cache::validateTags($tags);
+    assert(Inspector::assertAllStrings($tags), 'Cache Tags must be strings.');
 
     // Notify all added cache tags invalidators.
     foreach ($this->invalidators as $invalidator) {
diff --git a/core/lib/Drupal/Core/Cache/DatabaseBackend.php b/core/lib/Drupal/Core/Cache/DatabaseBackend.php
index 06c5dc2..43608ab 100644
--- a/core/lib/Drupal/Core/Cache/DatabaseBackend.php
+++ b/core/lib/Drupal/Core/Cache/DatabaseBackend.php
@@ -7,6 +7,7 @@
 
 namespace Drupal\Core\Cache;
 
+use Drupal\Component\Assertion\Inspector;
 use Drupal\Component\Utility\Crypt;
 use Drupal\Core\Database\Connection;
 use Drupal\Core\Database\SchemaObjectExistsException;
@@ -199,7 +200,7 @@ protected function doSetMultiple(array $items) {
         'tags' => array(),
       );
 
-      Cache::validateTags($item['tags']);
+      assert(Inspector::assertAllStrings($item['tags']), 'Cache Tags must be strings.');
       $item['tags'] = array_unique($item['tags']);
       // Sort the cache tags so that they are stored consistently in the DB.
       sort($item['tags']);
diff --git a/core/lib/Drupal/Core/Cache/MemoryBackend.php b/core/lib/Drupal/Core/Cache/MemoryBackend.php
index 5c7f928..5aebd7b 100644
--- a/core/lib/Drupal/Core/Cache/MemoryBackend.php
+++ b/core/lib/Drupal/Core/Cache/MemoryBackend.php
@@ -7,6 +7,8 @@
 
 namespace Drupal\Core\Cache;
 
+use Drupal\Component\Assertion\Inspector;
+
 /**
  * Defines a memory cache implementation.
  *
@@ -107,7 +109,7 @@ protected function prepareItem($cache, $allow_invalid) {
    * Implements Drupal\Core\Cache\CacheBackendInterface::set().
    */
   public function set($cid, $data, $expire = Cache::PERMANENT, array $tags = array()) {
-    Cache::validateTags($tags);
+    assert(Inspector::assertAllStrings($tags), 'Cache Tags must be strings.');
     $tags = array_unique($tags);
     // Sort the cache tags so that they are stored consistently in the database.
     sort($tags);
diff --git a/core/lib/Drupal/Core/Plugin/DefaultPluginManager.php b/core/lib/Drupal/Core/Plugin/DefaultPluginManager.php
index 7c8799a..38f2a21 100644
--- a/core/lib/Drupal/Core/Plugin/DefaultPluginManager.php
+++ b/core/lib/Drupal/Core/Plugin/DefaultPluginManager.php
@@ -7,6 +7,7 @@
 
 namespace Drupal\Core\Plugin;
 
+use Drupal\Component\Assertion\Inspector;
 use Drupal\Component\Plugin\Discovery\CachedDiscoveryInterface;
 use Drupal\Component\Plugin\Discovery\DiscoveryCachedTrait;
 use Drupal\Core\Plugin\Discovery\ContainerDerivativeDiscoveryDecorator;
@@ -154,7 +155,7 @@ public function __construct($subdir, \Traversable $namespaces, ModuleHandlerInte
    *   definitions should be cleared along with other, related cache entries.
    */
   public function setCacheBackend(CacheBackendInterface $cache_backend, $cache_key, array $cache_tags = array()) {
-    Cache::validateTags($cache_tags);
+    assert(Inspector::assertAllStrings($cache_tags), 'Cache Tags must be strings.');
     $this->cacheBackend = $cache_backend;
     $this->cacheKey = $cache_key;
     $this->cacheTags = $cache_tags;
diff --git a/core/modules/system/src/Tests/Cache/GenericCacheBackendUnitTestBase.php b/core/modules/system/src/Tests/Cache/GenericCacheBackendUnitTestBase.php
index cc0d9df..d3b0b74 100644
--- a/core/modules/system/src/Tests/Cache/GenericCacheBackendUnitTestBase.php
+++ b/core/modules/system/src/Tests/Cache/GenericCacheBackendUnitTestBase.php
@@ -218,13 +218,20 @@ public function testSetGet() {
     $this->assertEqual('value', $backend->get('TEST8')->data);
     $this->assertFalse($backend->get('test8'));
 
-    // Calling ::set() with invalid cache tags.
+    // Find the current runtime assertion mode.
+    $assertion_mode = assert_options(ASSERT_ACTIVE);
+    // Calling ::set() with invalid cache tags. This should fail an assertion.
     try {
-      $backend->set('exception_test', 'value', Cache::PERMANENT, ['node' => [3, 5, 7]]);
-      $this->fail('::set() was called with invalid cache tags, no exception was thrown.');
+      // Force assertions active, otherwise this will fail.
+      assert_options(ASSERT_ACTIVE, 1);
+      $backend->set('assertion_test', 'value', Cache::PERMANENT, ['node' => [3, 5, 7]]);
+      $this->fail('::set() was called with invalid cache tags, runtime assertion did not fail.');
     }
-    catch (\LogicException $e) {
-      $this->pass('::set() was called with invalid cache tags, an exception was thrown.');
+    catch (\AssertionError $e) {
+      $this->pass('::set() was called with invalid cache tags, runtime assertion failed.');
+    }
+    finally {
+      assert_options(ASSERT_ACTIVE, $assertion_mode);
     }
   }
 
@@ -412,18 +419,27 @@ public function testSetMultiple() {
 
     $this->assertEqual($cached['cid_5']->data, $items['cid_5']['data'], 'New cache item set correctly.');
 
-    // Calling ::setMultiple() with invalid cache tags.
+    // Find the current runtime assertion mode.
+    $assertion_mode = assert_options(ASSERT_ACTIVE);
+
+    // Calling ::setMultiple() with invalid cache tags. This should fail an assertion.
     try {
+      // Force assertions active, otherwise this will fail.
+      assert_options(ASSERT_ACTIVE, 1);
+
       $items = [
         'exception_test_1' => array('data' => 1, 'tags' => []),
         'exception_test_2' => array('data' => 2, 'tags' => ['valid']),
         'exception_test_3' => array('data' => 3, 'tags' => ['node' => [3, 5, 7]]),
       ];
       $backend->setMultiple($items);
-      $this->fail('::setMultiple() was called with invalid cache tags, no exception was thrown.');
+      $this->fail('::setMultiple() was called with invalid cache tags, runtime assertion did not fail.');
+    }
+    catch (\AssertionError $e) {
+      $this->pass('::setMultiple() was called with invalid cache tags, runtime assertion failed.');
     }
-    catch (\LogicException $e) {
-      $this->pass('::setMultiple() was called with invalid cache tags, an exception was thrown.');
+    finally {
+      assert_options(ASSERT_ACTIVE, $assertion_mode);
     }
   }
 
diff --git a/core/tests/Drupal/Tests/Core/Cache/CacheTest.php b/core/tests/Drupal/Tests/Core/Cache/CacheTest.php
index c2e61a1..be0e510 100644
--- a/core/tests/Drupal/Tests/Core/Cache/CacheTest.php
+++ b/core/tests/Drupal/Tests/Core/Cache/CacheTest.php
@@ -7,6 +7,7 @@
 
 namespace Drupal\Tests\Core\Cache;
 
+use Drupal\Component\Assertion\Inspector;
 use Drupal\Core\Cache\Cache;
 use Drupal\Tests\UnitTestCase;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
@@ -60,6 +61,32 @@ public function testValidateTags(array $tags, $expected_exception_message) {
   }
 
   /**
+   * Tests Drupal\Component\Assertion\Inspector::assertAllStrings
+   *
+   * Inspector is replacing ::validateTags, so for regression testing it must
+   * return correctly on the same test data. It returns boolean instead of
+   * throwing an exception when the tags are invalid, so this is reflected in
+   * the test below.  In practice the Inspector is called from the assert()
+   * statement which will throw \AssertionError when the tags are invalid.
+   *
+   * @covers Drupal\Component\Assertion\Inspector::assertAllStrings
+   *
+   * @dataProvider validateTagsProvider
+   */
+  public function testInspectorAssertAllStrings(array $tags, $expected_exception_message) {
+    // If no exception is expected for ::validateTags then the Inspector should
+    // return TRUE
+    if ($expected_exception_message === FALSE) {
+      $this->assertTrue(Inspector::assertAllStrings($tags));
+    }
+    // Otherwise it returns FALSE.  Unlike the function it replaces, it returns
+    // boolean.
+    else {
+      $this->assertFalse(Inspector::assertAllStrings($tags));
+    }
+  }
+
+  /**
    * Provides a list of pairs of cache tags arrays to be merged.
    *
    * @return array