Re: Previous discussions about generics syntax only?

Hi Ilija,

The optimizer, including type inference, is limited to the scope of the current file (along with internal functions/classes). [...] Preloading is the exception, where all preloaded files can assume not to be changed after PHP has booted.

Well, I was actually thinking of enabling these compile-time checks only if preloading is enabled, to ensure the closed-world guarantee.

We could make type checking a CLI step but how is that really better than PHPStan or Psalm at that point

Yeah don't really like the idea of a separate "typechecking" step either, I'd really love for this to be an integral part of the execution process, not as a separate static analysis step.

PHPStan and Psalm are arguably successful *because* they are written in PHP, making them much easier to maintain and contribute to. Agreed, however if at least some static analysis functionality is already implemented, I see no reason to not make use of it, even if

PHP does not accurately represent arrays in the optimizer and has no notion of array shapes. personally I really like array shapes but *only* as a stopgap measure while switching to full object DTOs, so I'm comfortable with the idea of not having static analysis for array shapes (actually, I would absolutely love to just treat all array values as mixed during static analysis, though array/list generics might be nice and easy to implement...).

Another issue, specifically pertaining to generics, is that PHP has type coercion. In both weak and strict typing mode, a float function parameter will coerce an integer value. However, if generic types are erased at runtime then the VM cannot do coercion for foo<float>($int) (where function foo<T>(T $var)). This will require either accepting inaccurate runtime types, or establishing stricter static rules that do not match the existing behavior.

Well I'm all for stricter rules :) Regards, Daniil Gentili.