Yeah, the grandparent is only true if you don't want to do interesting things with the language, like nearly any but the most basic peephole optimization.

But a fun fact, if you know about single-pass compiling, you can figure out a lot of why the original C syntax is what it is. A declaration is a "reserve some memory" statement. Local variables had to be declared at the beginning of scope so that the compiler could deallocate them at scope close. Without an AST, the compiler had to produce instructions immediately.

With a true AST, you don't need such a restrictive syntax.

There are many other possible examples.