Maybe I fill find the time to clean it up and make it public. But did not find VM-types difficult to implement, the type just depends on some run-time value, so at the point in time where the size expression is evaluated, one stores the result in a hidden variable which the type refers to.

Looking forward to the release!

What I found troublesome were not really the caching of array count, but when and where should the side effect be represented in AST, for example this one: https://godbolt.org/z/rcT1d8WWe the puts() call is a side effect for automatic variable but completely ignored for static variable.

Yes, it is a bit of mess. We started to make this more precise in the C standard when those expression have to be evaluated, but there are still issues. And when this is involved extensions there are more issues. I think in this example, such initializer would not be allowed in ISO C. I also fixed many bugs in GCC .