Support more scalar types of psalm

[smoench]

Hey,
would it be possible to support more scalar types of psalm?
Some are already supported but those aren't:

• array-key
• trait-string
• callable-string
• numeric-string

I got this as a feature request deptrac/deptrac#329 but I think the best place would be here. So everyone can benefit.

[jaapio]

well technically this might be possible... but I'm not sure what we can do with a feature like that... psalm and phpstan do have more context than this library. the class-string for example is supported because we have enough context to know what it means. But for the others, I don't know.

I must admit that I never used them, so I don't know what this library should do with those types.

Can you explain what you expect from this library to happen?

[smoench]

Currently they are interpreted as an Object_-type. I expect they are resolved as its own type and I think there is no need for more context. This should be done by the tool using this library.

[jaapio]

Having them as new types might make sense since the current behavior is invalid anyway, classes like array-key cannot be defined. So I think we can at these types.

I would love to review a PR for this proposed types.

[mvriel]

Technically these are Pseudo-types derived from the type String; so new pseudotypes that extend the String type would be nice there. At least, that is my reading of this situation; correct me if I am wrong

[orklah]

Technically these are Pseudo-types derived from the type String

array-key is kinda different. It may be a string, but it may also be an int

[mvriel]

Oh wait, array-key; but that can be any key-type right? Because PHP arrays support more than ints and strings

[orklah]

Oh wait, array-key; but that can be any key-type right? Because PHP arrays support more than ints and strings

Technically, no.
PHP will cast everything into either string or int:
https://3v4l.org/PahFL

array-key is just an alias for int|string in the context of array keys. At least, it's the definition used by Psalm:
https://psalm.dev/r/a0dd544afe
Phpstan:
https://phpstan.org/r/8c98e657-b4f7-43b3-aec1-54dc6af4fd10

And probably Phan, I don't use it enough to be sure

[mvriel]

Thanks for clarifying that Orklah. It would mean that the array-key pseudo-type a bit of an odd one is since it is secretly a compound type of int and string. Special care is needed to support that one

[smoench]

I added a PR #112 where we could discuss how it could be implemented :-)