diff --git a/core/modules/views/lib/Drupal/views/Plugin/views/argument/ArgumentPluginBase.php b/core/modules/views/lib/Drupal/views/Plugin/views/argument/ArgumentPluginBase.php
index 117ade9..29d0aa1 100644
--- a/core/modules/views/lib/Drupal/views/Plugin/views/argument/ArgumentPluginBase.php
+++ b/core/modules/views/lib/Drupal/views/Plugin/views/argument/ArgumentPluginBase.php
@@ -884,7 +884,7 @@ function summary_sort($order, $by = NULL) {
    * @param $data
    *   The query results for the row.
    */
-  function summary_argument($data) {
+  public function summaryArgument($data) {
     return $data->{$this->base_alias};
   }
 
diff --git a/core/modules/views/lib/Drupal/views/Plugin/views/argument/DayDate.php b/core/modules/views/lib/Drupal/views/Plugin/views/argument/DayDate.php
index 003f50b..20a4b0e 100644
--- a/core/modules/views/lib/Drupal/views/Plugin/views/argument/DayDate.php
+++ b/core/modules/views/lib/Drupal/views/Plugin/views/argument/DayDate.php
@@ -43,7 +43,7 @@ function title() {
     return format_date(strtotime("2005" . "05" . $day . " 00:00:00 UTC"), 'custom', $this->format, 'UTC');
   }
 
-  function summary_argument($data) {
+  public function summaryArgument($data) {
     // Make sure the argument contains leading zeroes.
     return str_pad($data->{$this->base_alias}, 2, '0', STR_PAD_LEFT);
   }
diff --git a/core/modules/views/lib/Drupal/views/Plugin/views/argument/ManyToOne.php b/core/modules/views/lib/Drupal/views/Plugin/views/argument/ManyToOne.php
index 803d31a..bbab449 100644
--- a/core/modules/views/lib/Drupal/views/Plugin/views/argument/ManyToOne.php
+++ b/core/modules/views/lib/Drupal/views/Plugin/views/argument/ManyToOne.php
@@ -184,7 +184,7 @@ function summary_query() {
     return $this->summary_basics();
   }
 
-  function summary_argument($data) {
+  public function summaryArgument($data) {
     $value = $data->{$this->base_alias};
     if (empty($value)) {
       $value = 0;
diff --git a/core/modules/views/lib/Drupal/views/Plugin/views/argument/MonthDate.php b/core/modules/views/lib/Drupal/views/Plugin/views/argument/MonthDate.php
index 2618836..28eb904 100644
--- a/core/modules/views/lib/Drupal/views/Plugin/views/argument/MonthDate.php
+++ b/core/modules/views/lib/Drupal/views/Plugin/views/argument/MonthDate.php
@@ -42,7 +42,7 @@ function title() {
     return format_date(strtotime("2005" . $month . "15" . " 00:00:00 UTC"), 'custom', $this->format, 'UTC');
   }
 
-  function summary_argument($data) {
+ public function summaryArgument($data) {
     // Make sure the argument contains leading zeroes.
     return str_pad($data->{$this->base_alias}, 2, '0', STR_PAD_LEFT);
   }
diff --git a/core/modules/views/lib/Drupal/views/Plugin/views/argument/String.php b/core/modules/views/lib/Drupal/views/Plugin/views/argument/String.php
index 139bdd2..0c7ae78 100644
--- a/core/modules/views/lib/Drupal/views/Plugin/views/argument/String.php
+++ b/core/modules/views/lib/Drupal/views/Plugin/views/argument/String.php
@@ -241,7 +241,7 @@ public function query($group_by = FALSE) {
     }
   }
 
-  function summary_argument($data) {
+  public function summaryArgument($data) {
     $value = $this->caseTransform($data->{$this->base_alias}, $this->options['path_case']);
     if (!empty($this->options['transform_dash'])) {
       $value = strtr($value, ' ', '-');