PHP 8.1: add support for enums

[jrfnl]

PHP 8.1 introduced a new type of OO structure: enumerations, which uses the enum keyword / T_ENUM token.

Refs:

• https://wiki.php.net/rfc/enumerations

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PHP 8.1 | Collections::closedScopes(): add the T_ENUM token

Enums, like classes, interfaces and traits, are a closed scope structure, so the Collections::closedScopes() token array should include it.

PHP 8.1 | Scopes::isOOConstant(): add support for constants in enums

Alike classes, constants can be declared in an enum too.

This commit adds support for detecting whether a constant declared using the const keyword is within an enum structure to the Scopes::isOOConstant() method.

Includes adding the T_ENUM token to the Collections::ooConstantScopes() token array.

PHP 8.1 | Scopes::isOOMethod(): add support for enums

Alike classes, methods can be declared in an enum.

As the Scopes::isOOMethod() method uses the PHPCS based [BC]Tokens::$ooScopeTokens token array, in which T_ENUM was added in PHPCS 3.7.0, the Scopes::isOOMethod() method will correctly recognize methods within enums as OO methods.

This commit updates the documentation to indicate support for enums + adds tests to safeguard support.

PHP 8.1 | Scopes::isOOProperty(): add tests for enums

Unlike classes, properties are not allowed in enums.

This commit adds tests to ensure the Scopes::isOOProperty() method handles this correctly.

PHP 8.1 | BCFile/ObjectDeclarations::get[Declaration]Name(): sync with PHPCS / support enums

Enums are a named structure, so the BCFile/ObjectDeclarations::get[Declaration]Name() method should handle this correctly.

This commit syncs in the changes from upstream for the same.

Refs:

• PHP 8.1: Added enum support to sniffs squizlabs/PHP_CodeSniffer#3482

PHP 8.1 | BCFile/ObjectDeclarations::getClassProperties(): add test with enum

... to verify the method correctly throws an exception.

PHP 8.1 | BCFile/ObjectDeclarations::findImplementedInterfaceNames(): sync with PHPCS / add support for enums

An enum declaration can implement one or more interfaces.

This commit updates the File::findImplementedInterfaceNames() method to allow it to find the interfaces implemented by an enum as well.

Includes unit tests.

Includes adding the T_ENUM token to the Collections::ooCanImplement() token array.

Refs:

• PHP 8.1 | File::findImplementedInterfaceNames(): add support for enums implementing interfaces squizlabs/PHP_CodeSniffer#3578

PHP 8.1 | BCFile/Variables::getMemberProperties(): throw exception for properties in enum

Handle enums in the same way as interface properties (neither are supported by PHP).

Neither enums nor interfaces support properties being declared on them.

This adjusts the File::getMemberProperties() method to handle properties declared on an enumin the same way as properties declared on aninterface` were already being handled.

Includes unit tests.

Refs:

• PHP 8.1 | File::getMemberProperties(): handle enum properties same as interface properties squizlabs/PHP_CodeSniffer#3577

PHP 8.1 | Utils\UseStatements::getType(): update comment to document enum support