Monomorphize types when not going through layout_of_local

Author: oli-obk

src/librustc_mir/interpret/eval_context.rs

@@ -510,7 +510,8 @@ impl<'a, 'mir, 'tcx: 'mir, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tc
                 match local.state {
                     LocalState::Live(_) => {
                         // This needs to be properly initialized.
-                        let layout = self.layout_of(mir.local_decls[idx].ty)?;
+                        let ty = self.monomorphize(mir.local_decls[idx].ty)?;
+                        let layout = self.layout_of(ty)?;
                         local.state = LocalState::Live(self.uninit_operand(layout)?);
                         local.layout = Cell::new(Some(layout));
                     }

src/librustc_mir/interpret/place.rs

@@ -624,7 +624,7 @@ where
                     // their layout on return.
                     PlaceTy {
                         place: *return_place,
-                        layout: self.layout_of(self.frame().mir.return_ty())?,
+                        layout: self.layout_of(self.monomorphize(self.frame().mir.return_ty())?)?,
                     },
                 None => return err!(InvalidNullPointerUsage),
             },