tests/coverage/closure_unit_return.coverage

   LL|       |#![feature(coverage_attribute)]
   LL|       |//@ edition: 2021
   LL|       |
   LL|       |// Regression test for an inconsistency between functions that return the value
   LL|       |// of their trailing expression, and functions that implicitly return `()`.
   LL|       |
   LL|      1|fn explicit_unit() {
   LL|      0|    let closure = || {
   LL|      0|        ();
   LL|      0|    };
   LL|       |
   LL|      1|    drop(closure);
   LL|      1|    () // explicit return of trailing value
   LL|      1|}
   LL|       |
   LL|      1|fn implicit_unit() {
   LL|      0|    let closure = || {
   LL|      0|        ();
   LL|      0|    };
   LL|       |
   LL|      1|    drop(closure);
   LL|       |    // implicit return of `()`
   LL|      1|}
   LL|       |
   LL|       |#[coverage(off)]
   LL|       |fn main() {
   LL|       |    explicit_unit();
   LL|       |    implicit_unit();
   LL|       |}