From b435e5b4c0f4f73fc0540cfaa3c82b8cedd79448 Mon Sep 17 00:00:00 2001
From: Mattias Wallin <mattias@klingawallin.se>
Date: Thu, 19 Sep 2024 18:36:00 +0200
Subject: [PATCH] Preallocate missmatches in
 `JsonEmitter::add_misformatted_file`

The mismatches length is known to be equal to `diff.len()`.
---
 src/emitter/json.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/emitter/json.rs b/src/emitter/json.rs
index a99626f783d..49872cc0b8b 100644
--- a/src/emitter/json.rs
+++ b/src/emitter/json.rs
@@ -56,7 +56,7 @@ impl JsonEmitter {
         filename: &FileName,
         diff: Vec<Mismatch>,
     ) -> Result<(), io::Error> {
-        let mut mismatches = vec![];
+        let mut mismatches = Vec::with_capacity(diff.len());
         for mismatch in diff {
             let original_begin_line = mismatch.line_number_orig;
             let expected_begin_line = mismatch.line_number;