message: Fix build of this test.
  Fixes build portion of `cargo test --all`.
diff: @@ -61,7 +61,7 @@ impl fmt::Display for SourceLoc {
  #[cfg(test)]
  mod tests {
  use super::SourceLoc;
  - use crate::std::string::ToString;
  + use crate::lib::std::string::ToString;
  #[test]
  fn display() {
  