Statements in class static blocks do not narrow types

[AumyF]

Bug Report

🔎 Search Terms

control flow analysis, class static blocks

🕗 Version & Regression Information

• v4.4.0-beta
• v4.4.0-dev.20210708
• This is the behavior in every version I tried, and I reviewed the proposal
• I was unable to test this on prior versions because class static blocks were added in 4.4.0

⏯ Playground Link

Playground link with relevant code

💻 Code

let foo: number;

class C {
  static {
    foo = 3;
  }
}

console.log(foo);

🙁 Actual behavior

An error Variable 'foo' is used before being assigned.(2454) occurs at line 10, console.log(foo).

🙂 Expected behavior

Code compiles without errors.

[tchetwin]

I accidentally duplicated this in #45023. Carrying over a point from there:

"Side effects" in initialization of static fields already behaved similarly (since ~forever):

let c: number;
class C {
  static f = (c = 10);
}
c; // Variable 'c' is used before being assigned.(2454)

[fwienber]

What about this even simpler case:

class Foo {
    static {
        Foo.doSomething(); // Error: "Property 'doSomething' is used before its initialization.(2729)"
    }

    // this is how Babel rewrites the above:
    static #_ = (() => {
        Foo.doSomething(); // Now, the forward reference is allowed!
    })();

    static doSomething(): void {
       console.log("gotcha!");
    }
}

This code on TypeScript Playground
Are class static blocks supposed to be more strict in this regard?
The Babel rewrite for class static blocks is to define an unused, #private static variable whose initializer is a self-evaluating arrow function. Using the rewrite, TypeScript does not complain about the forward reference.
At runtime, both variants work.
It seems to me that the TypeScript error should not be raised in this case.
Is this the same problem as above or should I create a separate issue?

[Zzzen]

I believe that's a separate issue.