Circular dependency check gets into way of perfectly valid type

[svatal]

Bug Report

🔎 Search Terms

7022, circular

🕗 Version & Regression Information

• This is the behavior in every version I tried, and I reviewed the FAQ for entries about Common "Bugs" That Aren't Bugs

⏯ Playground Link

Playground link with relevant code

💻 Code

let a : {prop: string} | undefined = undefined;
for (let x=0; x<2; x++) {
  const dep = a === undefined ? "a" : "b";
  a = {prop: dep}
}

🙁 Actual behavior

'dep' implicitly has type 'any' because it does not have a type annotation and is referenced directly or indirectly in its own initializer.

If not inside any type of cycle (e.g. while (true)), dep is correctly typed as "a" | "b" (see the playground link). So the actual value of a has not been used in the type information. Even if it has been the case, the cycle should break because a.prop is strongly defined and is not dependant in any case on the a = {prop: dep} assignment

🙂 Expected behavior

dep typed as "a" | "b" even in the cycle

Similar issues

I've found few simillar issues (e.g. 49837), but not one as simple as this case.

[MartinJohns]

Duplicate of #43047.

[svatal]

you are right, this one is quite similar, closing