diff --git a/src/lib.rs b/src/lib.rs
index 7329080ce1f7..34aead1a6300 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -442,7 +442,6 @@ impl WriteBackendMethods for GccCodegenBackend {
     }
     fn autodiff(
         _cgcx: &CodegenContext<Self>,
-        _tcx: TyCtxt<'_>,
         _module: &ModuleCodegen<Self::Module>,
         _diff_fncs: Vec<AutoDiffItem>,
         _config: &ModuleConfig,