error[E0601]: `main` function not found in crate `cfg_in_crate_1`
  --> $DIR/cfg-in-crate-1.rs:3:13
   |
LL | #![cfg(bar)]
   |             ^ consider adding a `main` function to `$DIR/cfg-in-crate-1.rs`

error: aborting due to 1 previous error

For more information about this error, try `rustc --explain E0601`.