From de2f7e15ba6db2846c80c7ad4ffe391f2c5a4311 Mon Sep 17 00:00:00 2001
From: Corey Farwell <coreyf@rwell.org>
Date: Sun, 19 Feb 2017 10:41:36 -0500
Subject: [PATCH] Rewrite `match` to use combinators.

---
 src/librustc/traits/error_reporting.rs | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/src/librustc/traits/error_reporting.rs b/src/librustc/traits/error_reporting.rs
index 411e986f62d9..a9f3c54bd73e 100644
--- a/src/librustc/traits/error_reporting.rs
+++ b/src/librustc/traits/error_reporting.rs
@@ -535,14 +535,10 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
                             return;
                         } else {
                             let trait_ref = trait_predicate.to_poly_trait_ref();
-                            let (post_message, pre_message) = match self.get_parent_trait_ref(
-                                &obligation.cause.code)
-                            {
-                                Some(t) => {
-                                    (format!(" in `{}`", t), format!("within `{}`, ", t))
-                                }
-                                None => (String::new(), String::new()),
-                            };
+                            let (post_message, pre_message) =
+                                self.get_parent_trait_ref(&obligation.cause.code)
+                                    .map(|t| (format!(" in `{}`", t), format!("within `{}`, ", t)))
+                                    .unwrap_or((String::new(), String::new()));
                             let mut err = struct_span_err!(
                                 self.tcx.sess,
                                 span,