consider wait() calls in nested bodies

clippy_lints/src/zombie_processes.rs

@@ -6,6 +6,7 @@
 use rustc_hir::intravisit::{Visitor, walk_block, walk_expr, walk_local};
 use rustc_hir::{Expr, ExprKind, HirId, LetStmt, Node, PatKind, Stmt, StmtKind};
 use rustc_lint::{LateContext, LateLintPass};
+use rustc_middle::hir::nested_filter;
 use rustc_session::declare_lint_pass;
 use rustc_span::sym;
 use std::ops::ControlFlow;
@@ -119,6 +120,7 @@ enum WaitFinder<'a, 'tcx> {
 }
 
 impl<'tcx> Visitor<'tcx> for WaitFinder<'_, 'tcx> {
+    type NestedFilter = nested_filter::OnlyBodies;
     type Result = ControlFlow<BreakReason>;
 
     fn visit_local(&mut self, l: &'tcx LetStmt<'tcx>) -> Self::Result {
@@ -204,6 +206,11 @@ fn visit_expr(&mut self, ex: &'tcx Expr<'tcx>) -> Self::Result {
 
         walk_expr(self, ex)
     }
+
+    fn nested_visit_map(&mut self) -> Self::Map {
+        let (Self::Found(cx, _) | Self::WalkUpTo(cx, _)) = self;
+        cx.tcx.hir()
+    }
 }
 
 /// This function has shared logic between the different kinds of nodes that can trigger the lint.

tests/ui/zombie_processes.rs

@@ -131,6 +131,13 @@ struct S {
         }
         x.wait().unwrap();
     }
+
+    {
+        let mut x = Command::new("").spawn().unwrap();
+        std::thread::spawn(move || {
+            x.wait().unwrap();
+        });
+    }
 }
 
 fn process_child(c: Child) {