diff --git a/src/modules.rs b/src/modules.rs
index 8e728f98cd1..3d4de51deb6 100644
--- a/src/modules.rs
+++ b/src/modules.rs
@@ -76,6 +76,6 @@ fn module_file(
 
     match parser::Parser::default_submod_path(id, dir_path, codemap).result {
         Ok(parser::ModulePathSuccess { path, .. }) => path,
-        Err(_) => panic!("Couldn't find module {}", id),
+        Err(_) => unreachable!("Couldn't find module {}", id),
     }
 }