From 6968e77baa01ab73588c5f260eaab5fab5f4caba Mon Sep 17 00:00:00 2001
From: Josh Stone <jistone@redhat.com>
Date: Mon, 13 May 2019 13:22:06 -0700
Subject: [PATCH] Fix new `?` inference errors in librustc_mir

---
 src/librustc_mir/hair/constant.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/librustc_mir/hair/constant.rs b/src/librustc_mir/hair/constant.rs
index caadc6055b5c6..f38b1a7cca804 100644
--- a/src/librustc_mir/hair/constant.rs
+++ b/src/librustc_mir/hair/constant.rs
@@ -17,7 +17,7 @@ crate fn lit_to_const<'a, 'gcx, 'tcx>(
 ) -> Result<ty::Const<'tcx>, LitToConstError> {
     use syntax::ast::*;
 
-    let trunc = |n| {
+    let trunc = |n| -> Result<_, LitToConstError> {
         let param_ty = ParamEnv::reveal_all().and(tcx.lift_to_global(&ty).unwrap());
         let width = tcx.layout_of(param_ty).map_err(|_| LitToConstError::Reported)?.size;
         trace!("trunc {} with size {} and shift {}", n, width.bits(), 128 - width.bits());