diff --git a/src/lib.rs b/src/lib.rs
index aa9faef..301692b 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -82,8 +82,11 @@ fn rewrite_dep_path_as_relative<P: AsRef<std::path::Path>>(dep: &mut Dependency,
     if let Dependency::Detailed(detail) = dep {
         detail.path = detail.path.as_mut().map(|path| {
             pathdiff::diff_paths(path, parent.as_ref())
-                .unwrap()
-                .to_string_lossy()
+                .expect(
+                    "Error rewriting dependency path as relative: unable to determing path diff.",
+                )
+                .to_str()
+                .expect("Error rewriting dependency path as relative: path diff is not UTF-8.")
                 .to_string()
         })
     }
@@ -662,5 +665,3 @@ fn dep2toml_item(dependency: &Dependency) -> toml_edit::Item {
 
             toml_edit::Item::Value(toml_edit::Value::InlineTable(table))
         }
-    }
-}