array as a generic type T (e.g. ClassName<array<array-key,mixed>>) causing a covariant issue

[gromson]

Hi everyone,

Please consider the following situation
https://phpstan.org/r/f2a2670e-223d-4d71-b8cd-01183962ff55

I've been hitting my head against a wall in vain for several hours struggling to understand the difference between createArrayDoer and createStringDoer in this particular case and why covariance error come into play.

I've read the "What’s Up With @template-covariant?" blog post but I still can't apply its points to this situation :(

I'd appreciate it if someone shared an idea of what is wrong here.

[gromson]

Alright, the problem is solved by defining ArrayStrategy as a generic type:
https://phpstan.org/r/17fc159d-467b-4ea9-a944-105fea139a97