fn propagate(&mut self) {
        let mut scanned = FxHashSet();
        while let Some(search_item) = self.worklist.pop() {
            if !scanned.insert(search_item) {
                continue
            }

            if let Some(ref item) = self.tcx.hir.find(search_item) {
                self.propagate_node(item, search_item);
            }
        }
    }
// Step 2: Mark all symbols that the symbols on the worklist touch.
Step 2: Mark all symbols that the symbols on the worklist touch.
Step 2 : Mark all symbols that the symbols on the worklist touch .
fn propagate(&mut self) {
        let mut scanned = FxHashSet();
        while let Some(search_item) = self.worklist.pop() {
            if !scanned.insert(search_item) {
                continue
            }
            if let Some(ref item) = self.tcx.hir.find(search_item) {
                self.propagate_node(item, search_item);
            }
        }
    }
fn propagate ( & mut self ) { let mut scanned = FxHashSet ( ) ; while let Some ( search_item ) = self . worklist . pop ( ) { if ! scanned . insert ( search_item ) { continue } if let Some ( ref item ) = self . tcx . hir . find ( search_item ) { self . propagate_node ( item , search_item ) ; } } }
Step 2: Mark all symbols that the symbols on the worklist touch.
Step 2 : Mark all symbols that the symbols on the worklist touch .
&mut self