Psalm support

[zerkms]

Feature Request

Q	A
New Feature	yes
RFC	no
BC Break	no

Summary

Are there any plans to add psalm-specific typing annotations the same way it already was added in doctrine/collections (eg https://github.com/doctrine/collections/blob/master/lib/Doctrine/Common/Collections/Collection.php#L29)

[Ocramius]

@zerkms overall 👍 to adding these from my end, but there's a huge list of PRs with required fixes that need attention too, so I won't be able to apply them myself.

I just finished covering Ocramius/ProxyManager#467 in a similar way, if anybody needs inspiration to work on this.

[orklah]

I think this can be closed now