warning: unreachable expression
  --> $DIR/issue-85071.rs:17:13
   |
LL |     let x = f();
   |             --- any code following this expression is unreachable
LL |
LL |     let _ = x;
   |             ^ unreachable expression
   |
note: this expression has type `Foo`, which is uninhabited
  --> $DIR/issue-85071.rs:15:13
   |
LL |     let x = f();
   |             ^^^
note: the lint level is defined here
  --> $DIR/issue-85071.rs:9:26
   |
LL | #![warn(unused_variables,unreachable_code)]
   |                          ^^^^^^^^^^^^^^^^

warning: unused variable: `x`
  --> $DIR/issue-85071.rs:15:9
   |
LL |     let x = f();
   |         ^ help: if this is intentional, prefix it with an underscore: `_x`
   |
note: the lint level is defined here
  --> $DIR/issue-85071.rs:9:9
   |
LL | #![warn(unused_variables,unreachable_code)]
   |         ^^^^^^^^^^^^^^^^

warning: 2 warnings emitted