diff --git a/core/lib/Drupal/Component/Utility/SafeMarkup.php b/core/lib/Drupal/Component/Utility/SafeMarkup.php
index 920335f..0d50cd6 100644
--- a/core/lib/Drupal/Component/Utility/SafeMarkup.php
+++ b/core/lib/Drupal/Component/Utility/SafeMarkup.php
@@ -64,23 +64,6 @@ public static function isSafe($string, $strategy = 'html') {
   }
 
   /**
-   * Safely concatenates strings by escaping any that are not known to be safe.
-   *
-   * @param string ...
-   *   An unlimited number of string parameters to concatenate.
-   *
-   * @return \Drupal\Component\Utility\SafeMarkup|string
-   *   The concatenated string, which is now also marked as safe.
-   *
-   * @todo
-   *   Should this (instead or additionally) accept an array of strings as a
-   *   parameter?
-   */
-  public static function concat() {
-    return SafeMarkup::implode('', func_get_args());
-  }
-
-  /**
    * Safely implodes strings by escaping any that are not known to be safe.
    *
    * @param string $delimiter
diff --git a/core/modules/file/file.module b/core/modules/file/file.module
index 4053a5c..fd20bcb 100644
--- a/core/modules/file/file.module
+++ b/core/modules/file/file.module
@@ -943,10 +943,10 @@ function file_save_upload($form_field_name, $validators = array(), $destination
           '#theme' => 'item_list',
           '#items' => $errors,
         );
-        $message = SafeMarkup::concat($message, drupal_render($item_list));
+        $message = SafeMarkup::implode('', array($message, drupal_render($item_list)));
       }
       else {
-        $message = SafeMarkup::concat($message, ' ', array_pop($errors));
+        $message = SafeMarkup::implode('', array($message, ' ', array_pop($errors)));
       }
       drupal_set_message($message, 'error');
       $files[$i] = FALSE;
diff --git a/core/modules/system/src/Tests/System/DateFormatsMachineNameTest.php b/core/modules/system/src/Tests/System/DateFormatsMachineNameTest.php
index a6f9189..34052dc 100644
--- a/core/modules/system/src/Tests/System/DateFormatsMachineNameTest.php
+++ b/core/modules/system/src/Tests/System/DateFormatsMachineNameTest.php
@@ -49,8 +49,7 @@ public function testDateFormatsMachineNameAllowedValues() {
       'date_format_pattern' => 'Y-m-d',
     );
     $this->drupalPostForm('admin/config/regional/date-time/formats/add', $edit, t('Add format'));
-    // @todo Revisit for a better solution.
-    $this->assertText(String::checkPlain('The machine-readable name must be unique, and can only contain lowercase letters, numbers, and underscores. Additionally, it can not be the reserved word "custom".'), 'It is not possible to create a date format with the machine name that has any character other than lowercase letters, digits or underscore.');
+    $this->assertText(t('The machine-readable name must be unique, and can only contain lowercase letters, numbers, and underscores. Additionally, it can not be the reserved word "custom".'), 'It is not possible to create a date format with the machine name that has any character other than lowercase letters, digits or underscore.');
 
     // Try to create a date format with the reserved machine name "custom".
     $edit = array(
@@ -59,8 +58,7 @@ public function testDateFormatsMachineNameAllowedValues() {
       'date_format_pattern' => 'Y-m-d',
     );
     $this->drupalPostForm('admin/config/regional/date-time/formats/add', $edit, t('Add format'));
-    // @todo Revisit for a better solution.
-    $this->assertText(String::checkPlain('The machine-readable name must be unique, and can only contain lowercase letters, numbers, and underscores. Additionally, it can not be the reserved word "custom".'), 'It is not possible to create a date format with the machine name "custom".');
+    $this->assertText(t('The machine-readable name must be unique, and can only contain lowercase letters, numbers, and underscores. Additionally, it can not be the reserved word "custom".'), 'It is not possible to create a date format with the machine name "custom".');
 
     // Try to create a date format with a machine name, "fallback", that
     // already exists.
diff --git a/core/modules/views/views.theme.inc b/core/modules/views/views.theme.inc
index c85ac89..01f7795 100644
--- a/core/modules/views/views.theme.inc
+++ b/core/modules/views/views.theme.inc
@@ -543,7 +543,7 @@ function template_preprocess_views_view_table(&$variables) {
             '#style' => $initial,
           );
           $markup = drupal_render($tablesort_indicator);
-          $label = SafeMarkup::concat($label, $markup);
+          $label = SafeMarkup::implode('', array($label, $markup));
         }
 
         $query['order'] = $field;
@@ -634,7 +634,7 @@ function template_preprocess_views_view_table(&$variables) {
         $field_output = $handler->getField($num, $field);
         $element_type = $fields[$field]->elementType(TRUE, TRUE);
         if ($element_type) {
-          $field_output = SafeMarkup::concat(SafeMarkup::set('<' . $element_type . '>'), $field_output, SafeMarkup::set('</' . $element_type . '>'));
+          $field_output = SafeMarkup::implode('', array(SafeMarkup::set('<' . $element_type . '>'), $field_output, SafeMarkup::set('</' . $element_type . '>')));
         }
 
         // Only bother with separators and stuff if the field shows up.
@@ -642,13 +642,13 @@ function template_preprocess_views_view_table(&$variables) {
           // Place the field into the column, along with an optional separator.
           if (!empty($column_reference['content'])) {
             if (!empty($options['info'][$column]['separator'])) {
-              $column_reference['content'] = SafeMarkup::concat($column_reference['content'], Xss::filterAdmin($options['info'][$column]['separator']));
+              $column_reference['content'] = SafeMarkup::implode('', array($column_reference['content'], Xss::filterAdmin($options['info'][$column]['separator'])));
             }
           }
           else {
             $column_reference['content'] = '';
           }
-          $column_reference['content'] = SafeMarkup::concat($column_reference['content'], $field_output);
+          $column_reference['content'] = SafeMarkup::implode('', array($column_reference['content'], $field_output));
         }
       }
       $column_reference['attributes'] = new Attribute($column_reference['attributes']);