pub type upvars_mentioned<'tcx> = Option<&'tcx IndexMap<HirId, Upvar, BuildHasherDefault<FxHasher>>>;
Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain
repr(...) attributes. Please see the Rust Reference’s “Type Layout” chapter for details on type layout guarantees.
Size: 8 bytes
Size for each variant:
None: 0 bytes
Some: 8 bytes