diff --git a/core/modules/comment/templates/field--comment.html.twig b/core/modules/comment/templates/field--comment.html.twig
index 67dcefb..16d9009 100644
--- a/core/modules/comment/templates/field--comment.html.twig
+++ b/core/modules/comment/templates/field--comment.html.twig
@@ -23,16 +23,16 @@
  */
 #}
 {%
-  set classes = [
+  attributes.addClass([
     'field',
     'field-' ~ entity_type|clean_class ~ '--' ~ field_name|clean_class,
     'field-name-' ~ field_name|clean_class,
     'field-type-' ~ field_type|clean_class,
-    'field-label-' ~ label_display|clean_class,
+    'field-label-' ~ label_display,
     'comment-wrapper'
-  ]
+  ])
 %}
-<section{{ attributes.addClass(classes) }}>
+<section{{ attributes }}>
   {% if comments and not label_hidden %}
     {{ title_prefix }}
     <h2{{ title_attributes.addClass('title') }}>{{ label }}</h2>
diff --git a/core/modules/node/templates/field--node--title.html.twig b/core/modules/node/templates/field--node--title.html.twig
index cce56d5..bb50423 100644
--- a/core/modules/node/templates/field--node--title.html.twig
+++ b/core/modules/node/templates/field--node--title.html.twig
@@ -16,12 +16,12 @@
  */
 #}
 {%
-  set classes = [
+  attributes.addClass([
     'field',
     'field-' ~ entity_type|clean_class ~ '--' ~ field_name|clean_class,
     'field-name-' ~ field_name|clean_class,
     'field-type-' ~ field_type|clean_class,
-    'field-label-' ~ label_display|clean_class
-  ]
+    'field-label-' ~ label_display
+  ])
 %}
-<span{{ attributes.addClass(classes) }}>{{ items }}</span>
+<span{{ attributes }}>{{ items }}</span>
diff --git a/core/modules/system/templates/field.html.twig b/core/modules/system/templates/field.html.twig
index eb5e2d2..26dbfc2 100644
--- a/core/modules/system/templates/field.html.twig
+++ b/core/modules/system/templates/field.html.twig
@@ -33,25 +33,25 @@
  * @ingroup themeable
  */
 #}
-{%
-  set classes = [
+{%-
+  attributes.addClass([
     'field',
     'field-' ~ entity_type|clean_class ~ '--' ~ field_name|clean_class,
     'field-name-' ~ field_name|clean_class,
     'field-type-' ~ field_type|clean_class,
-    'field-label-' ~ label_display|clean_class,
+    'field-label-' ~ label_display,
     label_display == 'inline' ? 'clearfix'
-  ]
-%}
-{%
-  set title_classes = [
+  ])
+-%}
+{%-
+  title_attributes.addClass([
     'field-label',
     label_display == 'visually_hidden' ? 'visually-hidden'
-  ]
-%}
-<div{{ attributes.addClass(classes) }}>
+  ])
+-%}
+<div{{ attributes }}>
   {% if not label_hidden %}
-    <div{{ title_attributes.addClass(title_classes) }}>{{ label }}:&nbsp;</div>
+    <div{{ title_attributes }}>{{ label }}:&nbsp;</div>
   {% endif %}
   <div{{ content_attributes.addClass('field-items') }}>
     {% for delta, item in items %}
diff --git a/core/themes/bartik/templates/field--taxonomy-term-reference.html.twig b/core/themes/bartik/templates/field--taxonomy-term-reference.html.twig
index 2bbbd57..14a86a8 100644
--- a/core/themes/bartik/templates/field--taxonomy-term-reference.html.twig
+++ b/core/themes/bartik/templates/field--taxonomy-term-reference.html.twig
@@ -16,26 +16,26 @@
  * @see bartik_preprocess_field()
  */
 #}
-{%
-  set classes = [
+{%-
+  attributes.addClass([
     'field',
     'field-' ~ entity_type|clean_class ~ '--' ~ field_name|clean_class,
     'field-name-' ~ field_name|clean_class,
     'field-type-' ~ field_type|clean_class,
-    'field-label-' ~ label_display|clean_class,
+    'field-label-' ~ label_display,
     label_display == 'inline' ? 'clearfix'
-  ]
-%}
-{%
-  set title_classes = [
-    field_type == 'taxonomy_term_reference' ? 'field-label',
+  ])
+-%}
+{%-
+  title_classes.addClass([
+    'field-label',
     label_display == 'inline' ? 'inline',
     label_display == 'visually_hidden' ? 'visually-hidden'
-  ]
-%}
-<div{{ attributes.addClass(classes) }}>
+  ])
+-%}
+<div{{ attributes }}>
   {% if not label_hidden %}
-    <h3{{ title_attributes.addClass(title_classes) }}>{{ label }}: </h3>
+    <h3{{ title_attributes }}>{{ label }}: </h3>
   {% endif %}
   <ul{{ content_attributes.addClass('links', 'field-items') }}>
     {% for delta, item in items %}