Repository navigation
Literal tested as key of a certain type cannot be used as an index type #57109
Description
🔎 Search Terms
"literal", "extends", "keyof", "cannot be used to index type", "conditional"
🕗 Version & Regression Information
Versions: ^5.0 (regression)
⏯ Playground Link
💻 Code
type T = {
k: symbol,
other: boolean, // another key seems required for the bug to appear
}
// Type '"k"' cannot be used as an index type.(2538)
type C = 'k' extends keyof T ? T['k'] : never; // any🙁 Actual behavior
An error is produced in the positive clause of the conditional type.
The resulting type is incorrect.
🙂 Expected behavior
No error.
Additional information about the issue
No response
Reacted by Joe Calzaretta and Craig P Hicks
Activity
[-]Literal tested as key of a certain type in condition cannot be used to index that type[/-][+]Literal tested as key of a certain type cannot be used to index that type[/+][-]Literal tested as key of a certain type cannot be used to index that type[/-][+]Literal tested as key of a certain type cannot be used as an index type[/+]craigphicks commentedon Jan 21, 2024
Weird. This works