9 files declare their use of PrimitiveInterface in Zircon Profile 8.0

BinaryInterface.php in core/lib/Drupal/Core/TypedData/Type/BinaryInterface.php

Contains \Drupal\Core\TypedData\Type\BinaryInterface.

BooleanInterface.php in core/lib/Drupal/Core/TypedData/Type/BooleanInterface.php

Contains \Drupal\Core\TypedData\Type\BooleanInterface.

FloatInterface.php in core/lib/Drupal/Core/TypedData/Type/FloatInterface.php

Contains \Drupal\Core\TypedData\Type\FloatInterface.

IntegerInterface.php in core/lib/Drupal/Core/TypedData/Type/IntegerInterface.php

Contains \Drupal\Core\TypedData\Type\IntegerInterface.

PrimitiveTypeConstraintValidatorTest.php in core/tests/Drupal/Tests/Core/Validation/Plugin/Validation/Constraint/PrimitiveTypeConstraintValidatorTest.php

Contains \Drupal\Tests\Core\Validation\Plugin\Validation\Constraint\PrimitiveTypeConstraintValidatorTest.

SchemaCheckTrait.php in core/lib/Drupal/Core/Config/Schema/SchemaCheckTrait.php

Contains \Drupal\Core\Config\Schema\SchemaCheckTrait.

StorableConfigBase.php in core/lib/Drupal/Core/Config/StorableConfigBase.php

Contains \Drupal\Core\Config\StorableConfigBase.

StringInterface.php in core/lib/Drupal/Core/TypedData/Type/StringInterface.php

Contains \Drupal\Core\TypedData\Type\StringInterface.

UriInterface.php in core/lib/Drupal/Core/TypedData/Type/UriInterface.php

Contains \Drupal\Core\TypedData\Type\UriInterface.