diff --git a/core/lib/Drupal/Core/StringTranslation/TranslationInterface.php b/core/lib/Drupal/Core/StringTranslation/TranslationInterface.php
index 1fda0e0..06b4115 100644
--- a/core/lib/Drupal/Core/StringTranslation/TranslationInterface.php
+++ b/core/lib/Drupal/Core/StringTranslation/TranslationInterface.php
@@ -33,7 +33,7 @@
    *      what is used to display the page.
    *   - 'context': The context the source string belongs to.
    *
-   * @return string
+   * @return string|\Drupal\Core\StringTranslation\TranslationWrapper
    *   The translated string.
    *
    * @see \Drupal\Component\Utility\SafeMarkup::format()
@@ -43,7 +43,7 @@ public function translate($string, array $args = array(), array $options = array
   /**
    * Renders a TranslationWrapper object to a string.
    *
-   * @param TranslationWrapper $translated_string
+   * @param \Drupal\Core\StringTranslation\TranslationWrapper $translated_string
    *   A TranslationWrapper object.
    *
    * @return string
diff --git a/core/lib/Drupal/Core/StringTranslation/TranslationManager.php b/core/lib/Drupal/Core/StringTranslation/TranslationManager.php
index 0dc9980..038ac52 100644
--- a/core/lib/Drupal/Core/StringTranslation/TranslationManager.php
+++ b/core/lib/Drupal/Core/StringTranslation/TranslationManager.php
@@ -148,7 +148,8 @@ public function translate($string, array $args = array(), array $options = array
       // If the string has arguments that start with '!' we consider it unsafe
       // and return the translation as a string for backward compatibility
       // purposes.
-      // @todo remove this temporary workaround.
+      // @todo https://www.drupal.org/node/2570037 remove this temporary
+      // workaround.
       if (0 === strpos($arg_key, '!') && !SafeMarkup::isSafe($args[$arg_key])) {
         $safe = FALSE;
         break;
@@ -173,15 +174,6 @@ public function renderTranslatedString(TranslationWrapper $translated_string) {
   }
 
   /**
-   * {@inheritdoc}
-   */
-  public function formatPlural($count, $singular, $plural, array $args = array(), array $options = array()) {
-    $translatable_string = implode(LOCALE_PLURAL_DELIMITER, array($singular, $plural));
-    $translated_strings = $this->doTranslate($translatable_string, $options);
-    return $this->formatPluralTranslated($count, $translated_strings, $args, $options);
-  }
-
-  /**
    * Translates a string to the current language or to a given language.
    *
    * @param string $string
@@ -208,6 +200,15 @@ protected function doTranslate($string, array $options = array()) {
   /**
    * {@inheritdoc}
    */
+  public function formatPlural($count, $singular, $plural, array $args = array(), array $options = array()) {
+    $translatable_string = implode(LOCALE_PLURAL_DELIMITER, array($singular, $plural));
+    $translated_strings = $this->doTranslate($translatable_string, $options);
+    return $this->formatPluralTranslated($count, $translated_strings, $args, $options);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
   public function formatPluralTranslated($count, $translation, array $args = array(), array $options = array()) {
     $args['@count'] = $count;
     $translated_array = explode(LOCALE_PLURAL_DELIMITER, $translation);
diff --git a/core/modules/locale/src/Tests/LocaleExportTest.php b/core/modules/locale/src/Tests/LocaleExportTest.php
index 50d23d7..061c161 100644
--- a/core/modules/locale/src/Tests/LocaleExportTest.php
+++ b/core/modules/locale/src/Tests/LocaleExportTest.php
@@ -64,7 +64,7 @@ public function testExportTranslation() {
     // Ensure we have a translation file.
     $this->assertRaw('# French translation of Drupal', 'Exported French translation file.');
     // Ensure our imported translations exist in the file.
-    $this->assertRaw($this->getTranslatedString(), 'French translations present in exported file.');
+    $this->assertRaw('msgstr "lundi"', 'French translations present in exported file.');
 
     // Import some more French translations which will be marked as customized.
     $name = tempnam('temporary://', "po2_") . '.po';
@@ -141,10 +141,8 @@ public function getPoFile() {
 "Content-Transfer-Encoding: 8bit\\n"
 "Plural-Forms: nplurals=2; plural=(n > 1);\\n"
 
-msgid "1 comment"
-msgid_plural "@count comments"
-msgstr[0] "1 commentaire"
-msgstr[1] "@count commentaires"
+msgid "Monday"
+msgstr "lundi"
 EOF;
   }
 
@@ -168,21 +166,6 @@ public function getCustomPoFile() {
   }
 
   /**
-   * Returns a .po file fragment with a translated string.
-   *
-   * @return string
-   *   A .po file fragment with a translated string.
-   */
-  function getTranslatedString() {
-    return <<< EOF
-msgid "1 comment"
-msgid_plural "@count comments"
-msgstr[0] "1 commentaire"
-msgstr[1] "@count commentaires"
-EOF;
-  }
-
-  /**
    * Returns a .po file fragment with an untranslated string.
    *
    * @return string
diff --git a/core/tests/Drupal/Tests/Core/StringTranslation/TranslationManagerTest.php b/core/tests/Drupal/Tests/Core/StringTranslation/TranslationManagerTest.php
index 4c9f8ef..6041e74 100644
--- a/core/tests/Drupal/Tests/Core/StringTranslation/TranslationManagerTest.php
+++ b/core/tests/Drupal/Tests/Core/StringTranslation/TranslationManagerTest.php
@@ -95,6 +95,8 @@ public function providerTestTranslatePlaceholder() {
     return [
       ['foo @bar', ['@bar' => 'bar'], 'foo bar', TRUE],
       ['bar !baz', ['!baz' => 'baz'], 'bar baz', FALSE],
+      ['bar @bar !baz', ['@bar' => 'bar', '!baz' => 'baz'], 'bar bar baz', FALSE],
+      ['bar !baz @bar', ['!baz' => 'baz', '@bar' => 'bar'], 'bar baz bar', FALSE],
     ];
   }
 }
diff --git a/core/tests/Drupal/Tests/UnitTestCase.php b/core/tests/Drupal/Tests/UnitTestCase.php
index 405e767..2b6e94f 100644
--- a/core/tests/Drupal/Tests/UnitTestCase.php
+++ b/core/tests/Drupal/Tests/UnitTestCase.php
@@ -222,6 +222,7 @@ public function getStringTranslationStub() {
         $wrapper = new TranslationWrapper($string, $args, $options);
         $wrapper->setStringTranslation($translation);
         // Pretend everything is not safe.
+        // @todo https://www.drupal.org/node/2570037 return the wrapper instead.
         return (string) $wrapper;
       });
     $translation->expects($this->any())