Re: Previous discussions about generics syntax only?

Hi Daniil On Fri, Nov 3, 2023 at 12:00 AM <daniil@daniil.it> wrote: > The much better approach, one that I intend to maybe give a shot at this Christmas, is to add > static analysis functionality to PHP itself (i.e. turn it into a truly statically typed language). > I have a hunch it may be easy enough to do by hooking into the type inference functionality > provided by opcache, and throw compile-time exceptions instead of silently inserting runtime > typechecks. The optimizer, including type inference, is limited to the scope of the current file (along with internal functions/classes). Each file is considered a "single compilation unit". When classes from different files reference each other, modifying one file does not require recompiling the other. However, this does mean that we cannot rely on information from other files as they may change at any point. Preloading is the exception, where all preloaded files can assume not to be changed after PHP has booted. We can obviously not limit type checking to preloaded files. We could make type checking a CLI step but how is that really better than PHPStan or Psalm at that point, other than having the official PHP stamp? PHPStan and Psalm are arguably successful *because* they are written in PHP, making them much easier to maintain and contribute to. I'd also like to add that tools like PHPStan and Psalm have much more accurate type representations. PHP does not accurately represent arrays in the optimizer and has no notion of array shapes. The optimizers types are biased towards speed rather than accuracy. 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. Ilija