diff --git a/src/librustc_mir/interpret/eval_context.rs b/src/librustc_mir/interpret/eval_context.rs
index b2db0fea3d09a..132b753eb9a62 100644
--- a/src/librustc_mir/interpret/eval_context.rs
+++ b/src/librustc_mir/interpret/eval_context.rs
@@ -282,12 +282,12 @@ impl<'a, 'mir, 'tcx: 'mir, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tc
         }
     }
 
-    pub fn monomorphize_in_frame<T: TypeFoldable<'tcx> + Subst<'tcx>>(
+    pub(super) fn monomorphize<T: TypeFoldable<'tcx> + Subst<'tcx>>(
         &self,
         t: T,
     ) -> EvalResult<'tcx, T> {
         match self.stack.last() {
-            Some(frame) => Ok(self.monomorphize(t, frame.instance.substs)),
+            Some(frame) => Ok(self.monomorphize_with_substs(t, frame.instance.substs)),
             None => if t.needs_subst() {
                 err!(TooGeneric).into()
             } else {
@@ -296,7 +296,7 @@ impl<'a, 'mir, 'tcx: 'mir, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tc
         }
     }
 
-    pub fn monomorphize<T: TypeFoldable<'tcx> + Subst<'tcx>>(
+    fn monomorphize_with_substs<T: TypeFoldable<'tcx> + Subst<'tcx>>(
         &self,
         t: T,
         substs: &'tcx Substs<'tcx>
@@ -315,7 +315,7 @@ impl<'a, 'mir, 'tcx: 'mir, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tc
         let cell = &frame.local_layouts[local];
         if cell.get().is_none() {
             let local_ty = frame.mir.local_decls[local].ty;
-            let local_ty = self.monomorphize(local_ty, frame.instance.substs);
+            let local_ty = self.monomorphize_with_substs(local_ty, frame.instance.substs);
             let layout = self.layout_of(local_ty)?;
             cell.set(Some(layout));
         }
diff --git a/src/librustc_mir/interpret/operand.rs b/src/librustc_mir/interpret/operand.rs
index 8995d091aaab6..8741571342f83 100644
--- a/src/librustc_mir/interpret/operand.rs
+++ b/src/librustc_mir/interpret/operand.rs
@@ -508,7 +508,7 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M>
 
             Constant(ref constant) => {
                 let layout = from_known_layout(layout, || {
-                    let ty = self.monomorphize_in_frame(mir_op.ty(self.mir(), *self.tcx))?;
+                    let ty = self.monomorphize(mir_op.ty(self.mir(), *self.tcx))?;
                     self.layout_of(ty)
                 })?;
                 let op = self.const_value_to_op(*constant.literal)?;
diff --git a/src/librustc_mir/interpret/step.rs b/src/librustc_mir/interpret/step.rs
index f1b4e6a5055b6..25f3e4c1f771d 100644
--- a/src/librustc_mir/interpret/step.rs
+++ b/src/librustc_mir/interpret/step.rs
@@ -248,7 +248,7 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M>
             }
 
             NullaryOp(mir::NullOp::SizeOf, ty) => {
-                let ty = self.monomorphize_in_frame(ty)?;
+                let ty = self.monomorphize(ty)?;
                 let layout = self.layout_of(ty)?;
                 assert!(!layout.is_unsized(),
                         "SizeOf nullary MIR operator called for unsized type");
@@ -260,7 +260,7 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M>
             }
 
             Cast(kind, ref operand, cast_ty) => {
-                debug_assert_eq!(self.monomorphize_in_frame(cast_ty)?, dest.layout.ty);
+                debug_assert_eq!(self.monomorphize(cast_ty)?, dest.layout.ty);
                 let src = self.eval_operand(operand, None)?;
                 self.cast(src, kind, dest)?;
             }