diff --git a/core/modules/migrate_drupal/src/Plugin/migrate/process/FieldNamePrefix.php b/core/modules/migrate_drupal/src/Plugin/migrate/process/FieldNamePrefix.php
new file mode 100644
index 0000000..f12cee8
--- /dev/null
+++ b/core/modules/migrate_drupal/src/Plugin/migrate/process/FieldNamePrefix.php
@@ -0,0 +1,32 @@
+<?php
+
+namespace Drupal\migrate_drupal\Plugin\migrate\process;
+
+use Drupal\Component\Utility\Unicode;
+use Drupal\migrate\MigrateException;
+use Drupal\migrate\MigrateExecutableInterface;
+use Drupal\migrate\ProcessPluginBase;
+use Drupal\migrate\Row;
+
+/**
+ * @MigrateProcessPlugin(
+ *   id = "field_name_prefix",
+ *   handle_multiples = TRUE
+ * )
+ */
+class FieldNamePrefix extends ProcessPluginBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function transform($value, MigrateExecutableInterface $migrate_executable, Row $row, $destination_property) {
+    if (is_array($value)) {
+      $new_value = implode('', $value);
+      return Unicode::substr($new_value, 0, 32);
+    }
+    else {
+      throw new MigrateException(sprintf('%s is not an array', var_export($value, TRUE)));
+    }
+  }
+
+}
diff --git a/core/modules/taxonomy/migration_templates/d6_vocabulary_entity_display.yml b/core/modules/taxonomy/migration_templates/d6_vocabulary_entity_display.yml
index e0f4625..e039d51 100644
--- a/core/modules/taxonomy/migration_templates/d6_vocabulary_entity_display.yml
+++ b/core/modules/taxonomy/migration_templates/d6_vocabulary_entity_display.yml
@@ -34,16 +34,10 @@ process:
       plugin: skip_on_empty
       method: row
   field_name:
-    # Prepend field_ to avoid conflicts with base fields, and make sure the
-    # result is no longer than 32 characters.
-    -
-      plugin: concat
-      source:
-        - constants/field_prefix
-        - '@raw_field_name'
-    -
-      plugin: substr
-      length: 32
+    plugin: field_name_prefix
+    source:
+      - 'constants/field_prefix'
+      - '@raw_field_name'
 destination:
   plugin: component_entity_display
 migration_dependencies:
diff --git a/core/modules/taxonomy/migration_templates/d6_vocabulary_entity_form_display.yml b/core/modules/taxonomy/migration_templates/d6_vocabulary_entity_form_display.yml
index 20bb0e4..6de1f1e 100644
--- a/core/modules/taxonomy/migration_templates/d6_vocabulary_entity_form_display.yml
+++ b/core/modules/taxonomy/migration_templates/d6_vocabulary_entity_form_display.yml
@@ -38,16 +38,10 @@ process:
       plugin: skip_on_empty
       method: row
   field_name:
-    # Prepend field_ to avoid conflicts with base fields, and make sure the
-    # result is no longer than 32 characters.
-    -
-      plugin: concat
-      source:
-        - constants/field_prefix
-        - '@raw_field_name'
-    -
-      plugin: substr
-      length: 32
+    plugin: field_name_prefix
+    source:
+      - 'constants/field_prefix'
+      - '@raw_field_name'
 destination:
   plugin: component_entity_form_display
 migration_dependencies:
diff --git a/core/modules/taxonomy/migration_templates/d6_vocabulary_field.yml b/core/modules/taxonomy/migration_templates/d6_vocabulary_field.yml
index bb4a942..8323ef4 100644
--- a/core/modules/taxonomy/migration_templates/d6_vocabulary_field.yml
+++ b/core/modules/taxonomy/migration_templates/d6_vocabulary_field.yml
@@ -22,16 +22,10 @@ process:
       plugin: skip_on_empty
       method: row
   field_name:
-    # Prepend field_ to avoid conflicts with base fields, and make sure the
-    # result is no longer than 32 characters.
-    -
-      plugin: concat
-      source:
-        - constants/field_prefix
-        - '@raw_field_name'
-    -
-      plugin: substr
-      length: 32
+    plugin: field_name_prefix
+    source:
+      - 'constants/field_prefix'
+      - '@raw_field_name'
   'settings/target_type': 'constants/target_entity_type'
   cardinality: cardinality
 destination:
diff --git a/core/modules/taxonomy/migration_templates/d6_vocabulary_field_instance.yml b/core/modules/taxonomy/migration_templates/d6_vocabulary_field_instance.yml
index 6d9ffa6..22ff7eb 100644
--- a/core/modules/taxonomy/migration_templates/d6_vocabulary_field_instance.yml
+++ b/core/modules/taxonomy/migration_templates/d6_vocabulary_field_instance.yml
@@ -29,16 +29,10 @@ process:
       plugin: skip_on_empty
       method: row
   field_name:
-    # Prepend field_ to avoid conflicts with base fields, and make sure the
-    # result is no longer than 32 characters.
-    -
-      plugin: concat
-      source:
-        - constants/field_prefix
-        - '@raw_field_name'
-    -
-      plugin: substr
-      length: 32
+    plugin: field_name_prefix
+    source:
+      - 'constants/field_prefix'
+      - '@raw_field_name'
   label: name
   'settings/handler': 'constants/selection_handler'
   'settings/handler_settings/target_bundles/0': '@field_name'
diff --git a/core/modules/taxonomy/tests/src/Kernel/Migrate/d6/MigrateTaxonomyTermTest.php b/core/modules/taxonomy/tests/src/Kernel/Migrate/d6/MigrateTaxonomyTermTest.php
index 12b9a9c..6450e4d 100644
--- a/core/modules/taxonomy/tests/src/Kernel/Migrate/d6/MigrateTaxonomyTermTest.php
+++ b/core/modules/taxonomy/tests/src/Kernel/Migrate/d6/MigrateTaxonomyTermTest.php
@@ -89,8 +89,8 @@ public function testTaxonomyTerms() {
       $language = isset($values['language']) ? $values['language'] . ' - ' : '';
       $this->assertSame("{$language}term {$tid} of vocabulary {$values['source_vid']}", $term->name->value);
       $this->assertSame("{$language}description of term {$tid} of vocabulary {$values['source_vid']}", $term->description->value);
-      $this->assertIdentical($values['vid'], $term->vid->target_id);
-      $this->assertIdentical((string) $values['weight'], $term->weight->value);
+      $this->assertSame($values['vid'], $term->vid->target_id);
+      $this->assertSame((string) $values['weight'], $term->weight->value);
       if ($values['parent'] === [0]) {
         $this->assertNull($term->parent->target_id);
       }
@@ -99,7 +99,7 @@ public function testTaxonomyTerms() {
         foreach (\Drupal::entityManager()->getStorage('taxonomy_term')->loadParents($tid) as $parent) {
           $parents[] = (int) $parent->id();
         }
-        $this->assertIdentical($parents, $values['parent']);
+        $this->assertSame($parents, $values['parent']);
       }
 
       $this->assertArrayHasKey($tid, $tree_terms, "Term $tid exists in vocabulary tree");
diff --git a/core/modules/taxonomy/tests/src/Kernel/Migrate/d6/MigrateTaxonomyVocabularyTest.php b/core/modules/taxonomy/tests/src/Kernel/Migrate/d6/MigrateTaxonomyVocabularyTest.php
index 6c66598..79e188b 100644
--- a/core/modules/taxonomy/tests/src/Kernel/Migrate/d6/MigrateTaxonomyVocabularyTest.php
+++ b/core/modules/taxonomy/tests/src/Kernel/Migrate/d6/MigrateTaxonomyVocabularyTest.php
@@ -32,17 +32,17 @@ public function testTaxonomyVocabulary() {
     for ($i = 0; $i < 3; $i++) {
       $j = $i + 1;
       $vocabulary = Vocabulary::load("vocabulary_{$j}_i_{$i}_");
-      $this->assertIdentical($this->getMigration('d6_taxonomy_vocabulary')->getIdMap()->lookupDestinationID([$j]), [$vocabulary->id()]);
-      $this->assertIdentical("vocabulary $j (i=$i)", $vocabulary->label());
-      $this->assertIdentical("description of vocabulary $j (i=$i)", $vocabulary->getDescription());
-      $this->assertIdentical($i, $vocabulary->getHierarchy());
-      $this->assertIdentical(4 + $i, $vocabulary->get('weight'));
+      $this->assertSame($this->getMigration('d6_taxonomy_vocabulary')->getIdMap()->lookupDestinationID([$j]), [$vocabulary->id()]);
+      $this->assertSame("vocabulary $j (i=$i)", $vocabulary->label());
+      $this->assertSame("description of vocabulary $j (i=$i)", $vocabulary->getDescription());
+      $this->assertSame($i, $vocabulary->getHierarchy());
+      $this->assertSame(4 + $i, $vocabulary->get('weight'));
     }
     $vocabulary = Vocabulary::load('vocabulary_name_much_longer_than');
-    $this->assertIdentical('vocabulary name much longer than thirty two characters', $vocabulary->label());
-    $this->assertIdentical('description of vocabulary name much longer than thirty two characters', $vocabulary->getDescription());
-    $this->assertIdentical(3, $vocabulary->getHierarchy());
-    $this->assertIdentical(7, $vocabulary->get('weight'));
+    $this->assertSame('vocabulary name much longer than thirty two characters', $vocabulary->label());
+    $this->assertSame('description of vocabulary name much longer than thirty two characters', $vocabulary->getDescription());
+    $this->assertSame(3, $vocabulary->getHierarchy());
+    $this->assertSame(7, $vocabulary->get('weight'));
   }
 
 }
diff --git a/core/modules/taxonomy/tests/src/Kernel/Migrate/d6/MigrateTermNodeRevisionTest.php b/core/modules/taxonomy/tests/src/Kernel/Migrate/d6/MigrateTermNodeRevisionTest.php
index e49f607..614725d 100644
--- a/core/modules/taxonomy/tests/src/Kernel/Migrate/d6/MigrateTermNodeRevisionTest.php
+++ b/core/modules/taxonomy/tests/src/Kernel/Migrate/d6/MigrateTermNodeRevisionTest.php
@@ -32,9 +32,9 @@ protected function setUp() {
    */
   public function testTermRevisionNode() {
     $node = \Drupal::entityManager()->getStorage('node')->loadRevision(2);
-    $this->assertIdentical(2, count($node->field_vocabulary_3_i_2_));
-    $this->assertIdentical('4', $node->field_vocabulary_3_i_2_[0]->target_id);
-    $this->assertIdentical('5', $node->field_vocabulary_3_i_2_[1]->target_id);
+    $this->assertSame(2, count($node->field_vocabulary_3_i_2_));
+    $this->assertSame('4', $node->field_vocabulary_3_i_2_[0]->target_id);
+    $this->assertSame('5', $node->field_vocabulary_3_i_2_[1]->target_id);
   }
 
 }
diff --git a/core/modules/taxonomy/tests/src/Kernel/Migrate/d6/MigrateTermNodeTest.php b/core/modules/taxonomy/tests/src/Kernel/Migrate/d6/MigrateTermNodeTest.php
index 1625800..8e7d13d 100644
--- a/core/modules/taxonomy/tests/src/Kernel/Migrate/d6/MigrateTermNodeTest.php
+++ b/core/modules/taxonomy/tests/src/Kernel/Migrate/d6/MigrateTermNodeTest.php
@@ -40,12 +40,12 @@ public function testTermNode() {
 
     $nodes = Node::loadMultiple([1, 2]);
     $node = $nodes[1];
-    $this->assertIdentical(1, count($node->field_vocabulary_1_i_0_));
-    $this->assertIdentical('1', $node->field_vocabulary_1_i_0_[0]->target_id);
+    $this->assertSame(1, count($node->field_vocabulary_1_i_0_));
+    $this->assertSame('1', $node->field_vocabulary_1_i_0_[0]->target_id);
     $node = $nodes[2];
-    $this->assertIdentical(2, count($node->field_vocabulary_2_i_1_));
-    $this->assertIdentical('2', $node->field_vocabulary_2_i_1_[0]->target_id);
-    $this->assertIdentical('3', $node->field_vocabulary_2_i_1_[1]->target_id);
+    $this->assertSame(2, count($node->field_vocabulary_2_i_1_));
+    $this->assertSame('2', $node->field_vocabulary_2_i_1_[0]->target_id);
+    $this->assertSame('3', $node->field_vocabulary_2_i_1_[1]->target_id);
   }
 
   /**
diff --git a/core/modules/taxonomy/tests/src/Kernel/Migrate/d6/MigrateVocabularyEntityDisplayTest.php b/core/modules/taxonomy/tests/src/Kernel/Migrate/d6/MigrateVocabularyEntityDisplayTest.php
index f121b1a..5b8a638 100644
--- a/core/modules/taxonomy/tests/src/Kernel/Migrate/d6/MigrateVocabularyEntityDisplayTest.php
+++ b/core/modules/taxonomy/tests/src/Kernel/Migrate/d6/MigrateVocabularyEntityDisplayTest.php
@@ -42,10 +42,10 @@ public function testVocabularyEntityDisplay() {
 
     // Test that the field exists.
     $component = EntityViewDisplay::load('node.page.default')->getComponent('field_tags');
-    $this->assertIdentical('entity_reference_label', $component['type']);
-    $this->assertIdentical(20, $component['weight']);
+    $this->assertSame('entity_reference_label', $component['type']);
+    $this->assertSame(20, $component['weight']);
     // Test the Id map.
-    $this->assertIdentical(['node', 'article', 'default', 'field_tags'], $this->getMigration('d6_vocabulary_entity_display')->getIdMap()->lookupDestinationID([4, 'article']));
+    $this->assertSame(['node', 'article', 'default', 'field_tags'], $this->getMigration('d6_vocabulary_entity_display')->getIdMap()->lookupDestinationID([4, 'article']));
 
     // Tests that a vocabulary named like a D8 base field will be migrated and
     // prefixed with 'field_' to avoid conflicts.
diff --git a/core/modules/taxonomy/tests/src/Kernel/Migrate/d6/MigrateVocabularyEntityFormDisplayTest.php b/core/modules/taxonomy/tests/src/Kernel/Migrate/d6/MigrateVocabularyEntityFormDisplayTest.php
index ad64522..2c96e51 100644
--- a/core/modules/taxonomy/tests/src/Kernel/Migrate/d6/MigrateVocabularyEntityFormDisplayTest.php
+++ b/core/modules/taxonomy/tests/src/Kernel/Migrate/d6/MigrateVocabularyEntityFormDisplayTest.php
@@ -42,15 +42,15 @@ public function testVocabularyEntityFormDisplay() {
 
     // Test that the field exists.
     $component = EntityFormDisplay::load('node.page.default')->getComponent('field_tags');
-    $this->assertIdentical('options_select', $component['type']);
-    $this->assertIdentical(20, $component['weight']);
+    $this->assertSame('options_select', $component['type']);
+    $this->assertSame(20, $component['weight']);
     // Test the Id map.
-    $this->assertIdentical(['node', 'article', 'default', 'field_tags'], $this->getMigration('d6_vocabulary_entity_form_display')->getIdMap()->lookupDestinationID([4, 'article']));
+    $this->assertSame(['node', 'article', 'default', 'field_tags'], $this->getMigration('d6_vocabulary_entity_form_display')->getIdMap()->lookupDestinationID([4, 'article']));
 
     // Test the term widget tags setting.
     $entity_form_display = EntityFormDisplay::load('node.story.default');
-    $this->assertIdentical($entity_form_display->getComponent('field_vocabulary_1_i_0_')['type'], 'options_select');
-    $this->assertIdentical($entity_form_display->getComponent('field_vocabulary_2_i_1_')['type'], 'entity_reference_autocomplete_tags');
+    $this->assertSame($entity_form_display->getComponent('field_vocabulary_1_i_0_')['type'], 'options_select');
+    $this->assertSame($entity_form_display->getComponent('field_vocabulary_2_i_1_')['type'], 'entity_reference_autocomplete_tags');
 
     // Tests that a vocabulary named like a D8 base field will be migrated and
     // prefixed with 'field_' to avoid conflicts.
diff --git a/core/modules/taxonomy/tests/src/Kernel/Migrate/d6/MigrateVocabularyFieldInstanceTest.php b/core/modules/taxonomy/tests/src/Kernel/Migrate/d6/MigrateVocabularyFieldInstanceTest.php
index 8814e60..26cd7f5 100644
--- a/core/modules/taxonomy/tests/src/Kernel/Migrate/d6/MigrateVocabularyFieldInstanceTest.php
+++ b/core/modules/taxonomy/tests/src/Kernel/Migrate/d6/MigrateVocabularyFieldInstanceTest.php
@@ -42,23 +42,23 @@ public function testVocabularyFieldInstance() {
     // Test that the field exists.
     $field_id = 'node.article.field_tags';
     $field = FieldConfig::load($field_id);
-    $this->assertIdentical($field_id, $field->id(), 'Field instance exists on article bundle.');
-    $this->assertIdentical('Tags', $field->label());
+    $this->assertSame($field_id, $field->id(), 'Field instance exists on article bundle.');
+    $this->assertSame('Tags', $field->label());
     $this->assertTrue($field->isRequired(), 'Field is required');
 
     // Test the page bundle as well.
     $field_id = 'node.page.field_tags';
     $field = FieldConfig::load($field_id);
-    $this->assertIdentical($field_id, $field->id(), 'Field instance exists on page bundle.');
-    $this->assertIdentical('Tags', $field->label());
+    $this->assertSame($field_id, $field->id(), 'Field instance exists on page bundle.');
+    $this->assertSame('Tags', $field->label());
     $this->assertTrue($field->isRequired(), 'Field is required');
 
     $settings = $field->getSettings();
-    $this->assertIdentical('default:taxonomy_term', $settings['handler'], 'The handler plugin ID is correct.');
-    $this->assertIdentical(['field_tags'], $settings['handler_settings']['target_bundles'], 'The target_bundles handler setting is correct.');
-    $this->assertIdentical(TRUE, $settings['handler_settings']['auto_create'], 'The "auto_create" setting is correct.');
+    $this->assertSame('default:taxonomy_term', $settings['handler'], 'The handler plugin ID is correct.');
+    $this->assertSame(['field_tags'], $settings['handler_settings']['target_bundles'], 'The target_bundles handler setting is correct.');
+    $this->assertSame(TRUE, $settings['handler_settings']['auto_create'], 'The "auto_create" setting is correct.');
 
-    $this->assertIdentical(['node', 'article', 'field_tags'], $this->getMigration('d6_vocabulary_field_instance')->getIdMap()->lookupDestinationID([4, 'article']));
+    $this->assertSame(['node', 'article', 'field_tags'], $this->getMigration('d6_vocabulary_field_instance')->getIdMap()->lookupDestinationID([4, 'article']));
 
     // Test the the field vocabulary_1_i_0_.
     $field_id = 'node.story.field_vocabulary_1_i_0_';
diff --git a/core/modules/taxonomy/tests/src/Kernel/Migrate/d6/MigrateVocabularyFieldTest.php b/core/modules/taxonomy/tests/src/Kernel/Migrate/d6/MigrateVocabularyFieldTest.php
index caa034b..d294ec4 100644
--- a/core/modules/taxonomy/tests/src/Kernel/Migrate/d6/MigrateVocabularyFieldTest.php
+++ b/core/modules/taxonomy/tests/src/Kernel/Migrate/d6/MigrateVocabularyFieldTest.php
@@ -33,13 +33,13 @@ public function testVocabularyField() {
     $field_storage_id = 'node.field_tags';
     /** @var \Drupal\field\FieldStorageConfigInterface $field_storage */
     $field_storage = FieldStorageConfig::load($field_storage_id);
-    $this->assertIdentical($field_storage_id, $field_storage->id());
+    $this->assertSame($field_storage_id, $field_storage->id());
 
     $settings = $field_storage->getSettings();
-    $this->assertIdentical('taxonomy_term', $settings['target_type'], "Target type is correct.");
-    $this->assertIdentical(1, $field_storage->getCardinality(), "Field cardinality in 1.");
+    $this->assertSame('taxonomy_term', $settings['target_type'], "Target type is correct.");
+    $this->assertSame(1, $field_storage->getCardinality(), "Field cardinality in 1.");
 
-    $this->assertIdentical(['node', 'field_tags'], $this->getMigration('d6_vocabulary_field')->getIdMap()->lookupDestinationID([4]), "Test IdMap");
+    $this->assertSame(['node', 'field_tags'], $this->getMigration('d6_vocabulary_field')->getIdMap()->lookupDestinationID([4]), "Test IdMap");
 
     // Tests that a vocabulary named like a D8 base field will be migrated and
     // prefixed with 'field_' to avoid conflicts.