message: Test whether a list is empty by looking at one value, no need for map + collect.
diff: @@ -77,14 +77,10 @@ impl Run {
  logging::set_up_logging().unwrap();
  }
  self.inner_execute().with_context(|| {
  - let compilers = CompilerType::enabled()
  - .iter()
  - .map(|c| c.to_string())
  - .collect::<Vec<String>>();
  format!(
  "failed to run `{}`{}",
  self.path.display(),
  - if compilers.is_empty() {
  + if CompilerType::enabled().iter().next().is_none() {
  " (no compilers enabled)"
  } else {
  ""
  