linear value escapes into a closure, task or `any`

Why this fires¶

A linear value escapes where the checker cannot follow it: a closure or task that may outlive its block captures it, it is cast to any, or it is stored in a binding typed any.

let tx = db.begin()?
let later = || tx.rollback()   // TE174

Tasks inside scope { } or parallel { } may borrow the value, since they are joined before the block ends, but they cannot consume it.

Fix it¶

Pass the value as a sink argument instead of capturing it, keep its type instead of any, or run the work inside scope { }.