diff --git a/compiler/rustc_session/src/config.rs b/compiler/rustc_session/src/config.rs
index f2bdabbf394..7dd9fdf60f9 100644
--- a/compiler/rustc_session/src/config.rs
+++ b/compiler/rustc_session/src/config.rs
@@ -798,6 +798,7 @@ pub enum DumpSolverProofTree {
     Never,
 }
 
+#[derive(Clone)]
 pub enum Input {
     /// Load source code from a file.
     File(PathBuf),