PHP 8

[i582]

All development will take place in the php8_dev branch.
We use grammar files from PHP-Parser.

The following parts need to be done.

• nullsafe operator (?->) #10
• Remove (real) cast #11
• Named arguments #13
• Remove (unset) cast #15
• Remove {} access #17
• match expression #19
• Union types in type hints and static typehint #21
• Block catch without variable #23
• Trailing comma in parameter lists #25
• throw can be used as an expression #27
• Concatenation precedence #30
• Declaring properties in the constructor #32
• Attributes #34
• Names in the namespace are treated as a single token #36
• Trailing comma in closure use list #38
• Check that ::class on object works #40
• Deferencable changes and arbitrary expressions in new/instanceof #42

When starting work on each item, you need to create a separate issue with a description,
and the created PR must be marked as closing the created issue.
The description should have a link to the RFC, as well as a short description + examples.

All new tests should be written in files with the php8_test suffix using the tester package. If the package
does not contain the required test type, then it is advisable to write the test suite for it in a separate PR.

After all the tasks are done, we will create a list of projects using PHP 8 on which we will do complex testing.
The list will be compiled in #2.

[i582]

See nikic/PHP-Parser#769 and nikic/PHP-Parser@e03d63c

[i582]

See nikic/PHP-Parser@2d19989