Borrow checker error on nightly even when the type is 'static #106332
Description
Compiling the binstalk from cargo-bins/cargo-binstall#646 failed on nightly due to lifetime error while it works on stable.
The code in question looks like this and is in taken from crates/binstalk/src/fetchers/gh_crate_meta.rs
pub struct GhCrateMeta { client: Client, data: Arc<Data>, target_data: Arc<TargetData>, resolution: OnceCell<(Url, PkgFmt)>, } type FindTaskRes = Result<Option<(Url, PkgFmt)>, BinstallError>; impl GhCrateMeta { fn launch_baseline_find_tasks<'a>( &'a self, pkg_fmt: PkgFmt, pkg_url: &'a str, repo: Option<&'a str>, ) -> impl Iterator<Item = impl Future<Output = FindTaskRes> + 'static> + 'a { todo!() } fn find(self: Arc<Self>) -> AutoAbortJoinHandle<Result<bool, BinstallError>> { AutoAbortJoinHandle::spawn(async move { // ... let mut handles = FuturesUnordered::new(); // Iterate over pkg_urls to avoid String::clone. for pkg_url in pkg_urls { // Clone iter pkg_fmts to ensure all pkg_fmts is // iterated over for each pkg_url, which is // basically cartesian product. // | for pkg_fmt in pkg_fmts.clone() { handles.extend(this.launch_baseline_find_tasks(pkg_fmt, &pkg_url, repo)); } } todo!() }) }On nightly, this failed with:
error[E0597]: `pkg_url` does not live long enough --> crates/binstalk/src/fetchers/gh_crate_meta.rs:147:77 | 147 | handles.extend(this.launch_baseline_find_tasks(pkg_fmt, &pkg_url, repo)); | ^^^^^^^^ borrowed value does not live long enough 148 | } 149 | } | - `pkg_url` dropped here while still borrowed ... 160 | }) | - borrow might be used here, when `handles` is dropped and runs the `Drop` code for type `Fu turesUnordered` | = note: values in a scope are dropped in the opposite order they are defined For more information about this error, try `rustc --explain E0597`. error: could not compile `binstalk` due to previous error warning: build failed, waiting for other jobs to finish... error: could not compile `binstalk` due to previous error Meta
rustc +nightly --version --verbose:
rustc 1.68.0-nightly (ce85c9857 2022-12-30) binary: rustc commit-hash: ce85c98575e3016cf2007d90a85be321e592aa96 commit-date: 2022-12-30 host: aarch64-apple-darwin release: 1.68.0-nightly LLVM version: 15.0.6