From b0fd642de61f23e0913c8476840e5921d7802309 Mon Sep 17 00:00:00 2001
From: Michael Howell <michael@notriddle.com>
Date: Thu, 11 Nov 2021 13:56:32 -0700
Subject: [PATCH] Use `Vec::extend`, instead of calling `Vec::push` in a loop

---
 compiler/rustc_mir_build/src/thir/pattern/usefulness.rs | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/compiler/rustc_mir_build/src/thir/pattern/usefulness.rs b/compiler/rustc_mir_build/src/thir/pattern/usefulness.rs
index d959d2f7f6f..b253108f3dc 100644
--- a/compiler/rustc_mir_build/src/thir/pattern/usefulness.rs
+++ b/compiler/rustc_mir_build/src/thir/pattern/usefulness.rs
@@ -443,9 +443,7 @@ pub(super) fn column_count(&self) -> Option<usize> {
     /// expands it.
     fn push(&mut self, row: PatStack<'p, 'tcx>) {
         if !row.is_empty() && row.head().is_or_pat() {
-            for row in row.expand_or_pat() {
-                self.patterns.push(row);
-            }
+            self.patterns.extend(row.expand_or_pat());
         } else {
             self.patterns.push(row);
         }