From 0010fc8fec235d36d9264de07dbad4508eda0a8e Mon Sep 17 00:00:00 2001
From: Simon Vandel Sillesen <simon.vandel@gmail.com>
Date: Mon, 28 Dec 2020 23:19:35 +0100
Subject: [PATCH] use exhaustive pattern match to prevent future bugs

---
 compiler/rustc_mir/src/transform/instcombine.rs | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/compiler/rustc_mir/src/transform/instcombine.rs b/compiler/rustc_mir/src/transform/instcombine.rs
index 04ea2bb542e..47695985386 100644
--- a/compiler/rustc_mir/src/transform/instcombine.rs
+++ b/compiler/rustc_mir/src/transform/instcombine.rs
@@ -301,9 +301,18 @@ struct OptimizationList<'tcx> {
 
 impl<'tcx> OptimizationList<'tcx> {
     fn is_empty(&self) -> bool {
-        self.and_stars.is_empty()
-            && self.arrays_lengths.is_empty()
-            && self.unneeded_equality_comparison.is_empty()
-            && self.unneeded_deref.is_empty()
+        match self {
+            OptimizationList {
+                and_stars,
+                arrays_lengths,
+                unneeded_equality_comparison,
+                unneeded_deref,
+            } => {
+                and_stars.is_empty()
+                    && arrays_lengths.is_empty()
+                    && unneeded_equality_comparison.is_empty()
+                    && unneeded_deref.is_empty()
+            }
+        }
     }
 }