Renamed isObjectTypehint => isClassTypehint to avoid confusion when
'object' typehint support is implemented.

Not really a cmake expert. Changes look sound, but can't really judge whether they are correct. Generally looks fine to me, apart from installing the php.g grammar file.

Sure, but it's a rather large diff and I didn't want it to clutter up this review. I'll push it as a follow-up commit

__DIR__ is a constant holding the current directory of the file the constant is used in
__TRAIT__ is a constant holding the current name of the trait the constant is used in

Add more test cases in the completion test

Coding adjustments and added comments.

The changes look good, although I think it would be preferable to have the basic types in a separate commit from the more complicated ones like iterable, self, object, etc.

Fair enough, was just playing it safe :)

Fixed showing correct structure type for variadic arguments.

Correct base branch, try 2

Correct base branch

The changes are currently based on the 5.1 branch, but I couldn't verify them locally. Almost none of the tests pass for me :(
I tested the changes on master and there everything is fine.

Used PushValue

lgtm as well :)