message: If resolution was unsuccessful, then it should stay unsuccessful even if any version of a crate is unpublished.
diff: @@ -357,7 +357,32 @@ proptest! {
  }
  }
  - Err(_) => {}
  + Err(_) => {
  + // If resolution was unsuccessful, then it should stay unsuccessful
  + // even if any version of a crate is unpublished.
  + let summary_to_unpublish = index_to_unpublish.get(&input);
  + let new_reg = registry(
  + input
  + .iter()
  + .cloned()
  + .filter(|x| summary_to_unpublish != x)
  + .collect(),
  + );
  +
  + let res = resolve(
  + &pkg_id("root"),
  + vec![dep_req(&this.name(), &format!("={}", this.version()))],
  + &new_reg,
  + );
  +
  + prop_assert!(
  + res.is_err(),
  + "full index did not work for `{} = \"={}\"` but unpublishing {:?} fixed it!",
  + this.name(),
  + this.version(),
  + summary_to_unpublish
  + )
  + }
  }
  }
  }
  