diff --git a/core/lib/Drupal/Core/Config/Config.php b/core/lib/Drupal/Core/Config/Config.php
index 0a93f0c..f04bbe0 100644
--- a/core/lib/Drupal/Core/Config/Config.php
+++ b/core/lib/Drupal/Core/Config/Config.php
@@ -11,8 +11,9 @@
 use Drupal\Component\Utility\String;
 use Drupal\Core\Config\ConfigNameException;
 use Drupal\Core\Config\Context\ContextInterface;
-use Drupal\Core\Config\TypedConfigManager;
 use Drupal\Core\TypedData\PrimitiveInterface;
+use Drupal\Core\TypedData\Type\FloatInterface;
+use Drupal\Core\TypedData\Type\IntegerInterface;
 
 /**
  * Defines the default configuration object.
@@ -522,6 +523,9 @@ protected function getSchemaWrapper() {
    *   A string that maps to a key within the configuration data.
    *
    * @return \Drupal\Core\Config\Schema\Element
+   *
+   * @throws \Drupal\Core\Config\ConfigException
+   *   Thrown when schema is incomplete.
    */
   protected function getSchemaForKey($key) {
     $parts = explode('.', $key);
@@ -567,7 +571,7 @@ protected function castValue($key, $value) {
           // we have to special case the meaning of an empty string for numeric
           // types. In PHP this would be casted to a 0 but for the purposes of
           // configuration we need to treat this as a NULL.
-          if ($element->isNumericType() && $value === '') {
+          if ($value === '' && ($element instanceof IntegerInterface || $element instanceof FloatInterface)) {
             $value = NULL;
           }
           else {
diff --git a/core/lib/Drupal/Core/TypedData/Plugin/DataType/Float.php b/core/lib/Drupal/Core/TypedData/Plugin/DataType/Float.php
index f8a8120..029df13 100644
--- a/core/lib/Drupal/Core/TypedData/Plugin/DataType/Float.php
+++ b/core/lib/Drupal/Core/TypedData/Plugin/DataType/Float.php
@@ -31,11 +31,4 @@ class Float extends PrimitiveBase implements FloatInterface {
   public function getCastedValue() {
     return (float) $this->value;
   }
-
-  /**
-   * @inheritdoc
-   */
-  public function isNumericType() {
-    return TRUE;
-  }
 }
diff --git a/core/lib/Drupal/Core/TypedData/Plugin/DataType/Integer.php b/core/lib/Drupal/Core/TypedData/Plugin/DataType/Integer.php
index 58d902b..1f92fc9 100644
--- a/core/lib/Drupal/Core/TypedData/Plugin/DataType/Integer.php
+++ b/core/lib/Drupal/Core/TypedData/Plugin/DataType/Integer.php
@@ -31,11 +31,4 @@ class Integer extends PrimitiveBase implements IntegerInterface {
   public function getCastedValue() {
     return (int) $this->value;
   }
-
-  /**
-   * @inheritdoc
-   */
-  public function isNumericType() {
-    return TRUE;
-  }
 }
diff --git a/core/lib/Drupal/Core/TypedData/PrimitiveBase.php b/core/lib/Drupal/Core/TypedData/PrimitiveBase.php
index 6d24cfb..dae6dbe 100644
--- a/core/lib/Drupal/Core/TypedData/PrimitiveBase.php
+++ b/core/lib/Drupal/Core/TypedData/PrimitiveBase.php
@@ -36,11 +36,4 @@ public function setValue($value, $notify = TRUE) {
       $this->parent->onChange($this->name);
     }
   }
-
-  /**
-   * @inheritdoc
-   */
-  public function isNumericType() {
-    return FALSE;
-  }
 }
diff --git a/core/lib/Drupal/Core/TypedData/PrimitiveInterface.php b/core/lib/Drupal/Core/TypedData/PrimitiveInterface.php
index d7060f6..01ad0d9 100644
--- a/core/lib/Drupal/Core/TypedData/PrimitiveInterface.php
+++ b/core/lib/Drupal/Core/TypedData/PrimitiveInterface.php
@@ -34,11 +34,4 @@ public function setValue($value);
    * @return mixed
    */
   public function getCastedValue();
-
-  /**
-   * Returns TRUE if the primitive data type is numeric.
-   *
-   * @return bool
-   */
-  public function isNumericType();
 }
diff --git a/core/modules/config/lib/Drupal/config/Tests/ConfigSchemaTest.php b/core/modules/config/lib/Drupal/config/Tests/ConfigSchemaTest.php
index 763b102..663b456 100644
--- a/core/modules/config/lib/Drupal/config/Tests/ConfigSchemaTest.php
+++ b/core/modules/config/lib/Drupal/config/Tests/ConfigSchemaTest.php
@@ -7,7 +7,6 @@
 
 namespace Drupal\config\Tests;
 
-use Drupal\Core\Config\TypedConfig;
 use Drupal\Core\TypedData\Type\IntegerInterface;
 use Drupal\Core\TypedData\Type\StringInterface;
 use Drupal\simpletest\DrupalUnitTestBase;