diff --git a/src/interpreter/mod.rs b/src/interpreter/mod.rs
index 1a52434f9fc..999fec73bd7 100644
--- a/src/interpreter/mod.rs
+++ b/src/interpreter/mod.rs
@@ -1798,7 +1798,7 @@ impl IntegerExt for layout::Integer {
 }
 
 
-pub fn monomorphize_field_ty<'a, 'tcx:'a >(tcx: TyCtxt<'a, 'tcx, 'tcx>, f: ty::FieldDef<'tcx>, substs: &'tcx Substs<'tcx>) -> Ty<'tcx> {
+pub fn monomorphize_field_ty<'a, 'tcx:'a >(tcx: TyCtxt<'a, 'tcx, 'tcx>, f: &ty::FieldDef, substs: &'tcx Substs<'tcx>) -> Ty<'tcx> {
     let substituted = &f.ty(tcx, substs);
     tcx.normalize_associated_type(&substituted)
 }
diff --git a/src/interpreter/terminator/intrinsics.rs b/src/interpreter/terminator/intrinsics.rs
index 706fadd0ab4..1781211c9c7 100644
--- a/src/interpreter/terminator/intrinsics.rs
+++ b/src/interpreter/terminator/intrinsics.rs
@@ -489,8 +489,8 @@ impl<'a, 'tcx> EvalContext<'a, 'tcx> {
     fn field_ty(
         &self,
         param_substs: &Substs<'tcx>,
-        f: ty::FieldDef<'tcx>,
-    )-> ty::Ty<'tcx> {
+        f: &ty::FieldDef,
+    ) -> ty::Ty<'tcx> {
         self.tcx.normalize_associated_type(&f.ty(self.tcx, param_substs))
     }
 }