Typeguard not working if checked against Exclude

[qwelias]

Bug Report

🔎 Search Terms

typeguard exclude union

🕗 Version & Regression Information

v4.6.2

• This is the behavior in every version I tried, and I reviewed the FAQ for entries about typeguards

⏯ Playground Link

Playground link with relevant code

💻 Code

type AAA = {
    c: 0
    b: 1
} | {
    c: Exclude<number, 0>
    x: 1
}

const a = {} as unknown as AAA

if (a.c !== 0) a.x

🙁 Actual behavior

error

Property 'x' does not exist on type 'AAA'.
  Property 'x' does not exist on type '{ c: 0; b: 1; }'.

🙂 Expected behavior

no error

[MartinJohns]

The type Exclude<number, 0> is exactly the same type as number. It does not do what you think it does. There is no way to represent a type "any number, except 0" in TypeScript. This would first require #29317.

[qwelias]

thanks, tho it's been open for 3+yrs now...

[MartinJohns]

It's a fairly difficult issue to solve.