warning: trait `Trait` is never used
  --> $DIR/target-expr-pass.rs:17:7
   |
LL | trait Trait {
   |       ^^^^^
   |
   = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default

warning: struct `F` is never constructed
  --> $DIR/target-expr-pass.rs:21:8
   |
LL | struct F;
   |        ^

warning: struct `S` is never constructed
  --> $DIR/target-expr-pass.rs:24:8
   |
LL | struct S(F);
   |        ^

warning: 3 warnings emitted