PHP 8.3 | Tokenizer/PHP: add support for typed OO constants

[jrfnl]

Description

PHP 8.3 introduced typed OO constants, where the type is between the const keyword and the constant name.

All type variations are supported, including nullable types, union types, intersection types, with the exception of callable, void and never. self and static types are only allowed in Enum constants.

This PR adds support for typed OO constants in the Tokenizer layer of PHPCS.

The following issues had to be fixed to support typed constants:

1. Consistently tokenizing the constant name as T_STRING, even if the name mirrors a reserved keyword, like foreach or a special keyword, like self or true.
2. Tokenizing a ? at the start of a constant type declaration as T_NULLABLE.
3. Tokenizing a | and & operators within a constant type declaration as T_TYPE_UNION and T_TYPE_INTERSECTION respectively.

Each and every part of the above has been covered by extensive tests.
Includes additional tests safeguarding that the array keyword when used in a type declaration for a constant is tokenized as T_STRING.

Ref: https://wiki.php.net/rfc/typed_class_constants

Suggested changelog entry

• Added: Tokenizer support for PHP 8.3 typed class constants.

Related issues/external references

Related to #106

Types of changes

• New feature (non-breaking change which adds functionality)

[calinblaga]

Thanks for these adjustments!
I'm having this error Class constants must be uppercase; expected INT but found int using this branch as a dependency.
I know it's not included in the description of this PR, but any idea how can we address this case?

[jrfnl]

Thanks for these adjustments! I'm having this error Class constants must be uppercase; expected INT but found int using this branch as a dependency. I know it's not included in the description of this PR, but any idea how can we address this case?

@calinblaga You don't need to. This PR is a prerequisite for fixing the sniff and those changes have already been lined up and will be pulled once this PR has been merged. Also see #106.

[jrfnl]

Unless there are objections/someone leaves a comments on this PR, I will merge this tomorrow.

[jrfnl]

Rebased without changes. Merging once the build passes.