Type narrowing doesn't work inside constant ternary operator

[Noa-Ivix]

Bug Report

🔎 Search Terms

• Ternary narrowing
• Constant ternary
• Constant ternary narrowing

🕗 Version & Regression Information

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

⏯ Playground Link

Playground link with relevant code

💻 Code

function works1(s: number | null) {
  return s !== null ? s.toString() : ""
}
function works2(s: number | null) {
  return true ? (
      s !== null ? s.toString() : ""
    ) : "";
}
function doesnt_works(s: number | null) {
  return false ? (
      s !== null ? s.toString() : ""
                // ^ Object is possibly 'null'
    ) : "";
}

🙁 Actual behavior

Function doesnt_work fails to compile because s is assumed to be number | null even though we just checked that s !== null.

🙂 Expected behavior

This should either compile successfully or maybe produce an error/warning about unreachable code.
The expression s !== null ? s.toString() : "" was correct when used on its own but became invalid once I placed it in a false branch of a ternary operator, for no apparent reason.

[fatcerberus]

See #26914

[typescript-bot]

This issue has been marked as a 'Duplicate' and has seen no recent activity. It has been automatically closed for house-keeping purposes.