diff -u b/core/modules/node/src/Plugin/Search/NodeSearch.php b/core/modules/node/src/Plugin/Search/NodeSearch.php
--- b/core/modules/node/src/Plugin/Search/NodeSearch.php
+++ b/core/modules/node/src/Plugin/Search/NodeSearch.php
@@ -358,7 +358,7 @@
       }
 
       // Update index, using search index "type" equal to the plugin ID.
-      search_index($node->id(), $this->getPluginId(), $text, $language->getId());
+      search_index($this->getPluginId(), $node->id(), $language->getId(), $text);
     }
   }
 
diff -u b/core/modules/search/search.module b/core/modules/search/search.module
--- b/core/modules/search/search.module
+++ b/core/modules/search/search.module
@@ -368,19 +368,19 @@
 /**
  * Updates the full-text search index for a particular item.
  *
- * @param $sid
- *   An ID number identifying this particular item (e.g., node ID).
  * @param $type
  *   The plugin ID or other machine-readable type of this item,
  *   which should be less than 64 bytes.
- * @param $text
- *   The content of this item. Must be a piece of HTML or plain text.
+ * @param $sid
+ *   An ID number identifying this particular item (e.g., node ID).
  * @param $langcode
  *   Language code for text being indexed.
+ * @param $text
+ *   The content of this item. Must be a piece of HTML or plain text.
  *
  * @ingroup search
  */
-function search_index($sid, $type, $text, $langcode) {
+function search_index($type, $sid, $langcode, $text) {
   $minimum_word_size = \Drupal::config('search.settings')->get('index.minimum_word_size');
 
   // Multipliers for scores of words inside certain HTML tags. The weights are
@@ -516,7 +516,7 @@
  * @param int $sid
  *   (optional) An ID number identifying this particular item (e.g., node ID).
  *   If omitted, everything matching $type is marked, and $langcode is ignored.
- * @param strong $langcode
+ * @param string $langcode
  *   (optional) The language code to clear. If omitted, everything matching
  *   $type and $sid is marked.
  */
diff -u b/core/modules/search/src/Tests/SearchMultilingualEntityTest.php b/core/modules/search/src/Tests/SearchMultilingualEntityTest.php
--- b/core/modules/search/src/Tests/SearchMultilingualEntityTest.php
+++ b/core/modules/search/src/Tests/SearchMultilingualEntityTest.php
@@ -232,7 +232,7 @@
     // Add a bogus entry to the search index table using a different search
     // type. This will not appear in the index status, because it is not
     // managed by a plugin.
-    search_index($this->searchable_nodes[0]->id(), 'foo', 'some text', 'en');
+    search_index('foo', $this->searchable_nodes[0]->id(), 'en', 'some text');
     $this->assertIndexCounts(1, 8, 'after adding a different index item');
 
     // Mark just this "foo" index for reindexing.
only in patch2:
unchanged:
--- a/core/modules/search/src/Tests/SearchMatchTest.php
+++ b/core/modules/search/src/Tests/SearchMatchTest.php
@@ -36,10 +36,10 @@ function _setup() {
     \Drupal::config('search.settings')->set('index.minimum_word_size', 3)->save();
 
     for ($i = 1; $i <= 7; ++$i) {
-      search_index($i, SEARCH_TYPE, $this->getText($i), LanguageInterface::LANGCODE_NOT_SPECIFIED);
+      search_index(SEARCH_TYPE, $i, LanguageInterface::LANGCODE_NOT_SPECIFIED, $this->getText($i));
     }
     for ($i = 1; $i <= 5; ++$i) {
-      search_index($i + 7, SEARCH_TYPE_2, $this->getText2($i), LanguageInterface::LANGCODE_NOT_SPECIFIED);
+      search_index(SEARCH_TYPE_2, $i + 7, LanguageInterface::LANGCODE_NOT_SPECIFIED, $this->getText2($i));
     }
     // No getText builder function for Japanese text; just a simple array.
     foreach (array(
@@ -47,7 +47,7 @@ function _setup() {
       14 => 'ドルーパルが大好きよ！',
       15 => 'コーヒーとケーキ',
     ) as $i => $jpn) {
-      search_index($i, SEARCH_TYPE_JPN, $jpn, LanguageInterface::LANGCODE_NOT_SPECIFIED);
+      search_index(SEARCH_TYPE_JPN, $i, LanguageInterface::LANGCODE_NOT_SPECIFIED, $jpn);
     }
     search_update_totals();
   }