6 files declare their use of EntityReferenceFieldCreationTrait

ArgumentSummaryTest.php in core/modules/views/tests/src/Kernel/Handler/ArgumentSummaryTest.php
CommentEntityReferenceTest.php in core/modules/comment/tests/src/Functional/CommentEntityReferenceTest.php
ContentImportTest.php in core/tests/Drupal/FunctionalTests/DefaultContent/ContentImportTest.php
ManageFieldsFunctionalTestBase.php in core/modules/field_ui/tests/src/Functional/ManageFieldsFunctionalTestBase.php
TokenReplaceTest.php in core/modules/taxonomy/tests/src/Kernel/TokenReplaceTest.php
WorkspaceViewsIntegrationTest.php in core/modules/workspaces/tests/src/Kernel/WorkspaceViewsIntegrationTest.php

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