no error when comparing typeof to undefined or null

[DetachHead]

Bug Report

🔎 Search Terms

typeof undefined null

🕗 Version & Regression Information

v4.2.0-dev.20201223

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

⏯ Playground Link

Playground link with relevant code

💻 Code

//error: This condition will always return 'false' since the types
//'"string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"' and '"asdf"' have no overlap.
typeof undefined === 'asdf'

//no error, even though these conditions will also always be false:
typeof undefined === undefined
typeof undefined === null

🙁 Actual behavior

no error when comparing typeof undefined to null or undefined

🙂 Expected behavior

"This condition will always return 'false'" error, as there is no overlap with the return type of typeof (which is "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function")

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/typeof#Description

[MartinJohns]

Duplicate of #29405 / #29200. Used search terms: typeof undefined null in:title