   LL|       |#![feature(coverage_attribute, stmt_expr_attributes)]
   LL|       |//@ edition: 2021
   LL|       |//@ reference: attributes.coverage.nesting
   LL|       |
   LL|       |// Demonstrates the interaction between #[coverage(off)] and various kinds of
   LL|       |// nested function.
   LL|       |
   LL|       |#[coverage(off)]
   LL|       |fn do_stuff() {}
   LL|       |
   LL|       |#[coverage(off)]
   LL|       |fn outer_fn() {
   LL|       |    fn middle_fn() {
   LL|       |        fn inner_fn() {
   LL|       |            do_stuff();
   LL|       |        }
   LL|       |        do_stuff();
   LL|       |    }
   LL|       |    do_stuff();
   LL|       |}
   LL|       |
   LL|       |struct MyOuter;
   LL|       |impl MyOuter {
   LL|       |    #[coverage(off)]
   LL|       |    fn outer_method(&self) {
   LL|       |        struct MyMiddle;
   LL|       |        impl MyMiddle {
   LL|       |            fn middle_method(&self) {
   LL|       |                struct MyInner;
   LL|       |                impl MyInner {
   LL|       |                    fn inner_method(&self) {
   LL|       |                        do_stuff();
   LL|       |                    }
   LL|       |                }
   LL|       |                do_stuff();
   LL|       |            }
   LL|       |        }
   LL|       |        do_stuff();
   LL|       |    }
   LL|       |}
   LL|       |
   LL|       |trait MyTrait {
   LL|       |    fn trait_method(&self);
   LL|       |}
   LL|       |impl MyTrait for MyOuter {
   LL|       |    #[coverage(off)]
   LL|       |    fn trait_method(&self) {
   LL|       |        struct MyMiddle;
   LL|       |        impl MyTrait for MyMiddle {
   LL|       |            fn trait_method(&self) {
   LL|       |                struct MyInner;
   LL|       |                impl MyTrait for MyInner {
   LL|       |                    fn trait_method(&self) {
   LL|       |                        do_stuff();
   LL|       |                    }
   LL|       |                }
   LL|       |                do_stuff();
   LL|       |            }
   LL|       |        }
   LL|       |        do_stuff();
   LL|       |    }
   LL|       |}
   LL|       |
   LL|      1|fn closure_expr() {
   LL|      1|    let _outer = #[coverage(off)]
   LL|       |    || {
   LL|       |        let _middle = || {
   LL|       |            let _inner = || {
   LL|       |                do_stuff();
   LL|       |            };
   LL|       |            do_stuff();
   LL|       |        };
   LL|       |        do_stuff();
   LL|       |    };
   LL|      1|    do_stuff();
   LL|      1|}
   LL|       |
   LL|       |// This syntax is allowed, even without #![feature(stmt_expr_attributes)].
   LL|      1|fn closure_tail() {
   LL|      1|    let _outer = {
   LL|       |        #[coverage(off)]
   LL|       |        || {
   LL|       |            let _middle = {
   LL|       |                || {
   LL|       |                    let _inner = {
   LL|       |                        || {
   LL|       |                            do_stuff();
   LL|       |                        }
   LL|       |                    };
   LL|       |                    do_stuff();
   LL|       |                }
   LL|       |            };
   LL|       |            do_stuff();
   LL|       |        }
   LL|       |    };
   LL|      1|    do_stuff();
   LL|      1|}
   LL|       |
   LL|       |#[coverage(off)]
   LL|       |fn main() {
   LL|       |    outer_fn();
   LL|       |    MyOuter.outer_method();
   LL|       |    MyOuter.trait_method();
   LL|       |    closure_expr();
   LL|       |    closure_tail();
   LL|       |}