From 4c6d19d440461ff6cf14435ef7646ef47170805e Mon Sep 17 00:00:00 2001
From: Luca Bruno <lucab@lucabruno.net>
Date: Thu, 1 Aug 2024 00:41:27 +0200
Subject: [PATCH] perf(allocator): use capacity hint (#4584)

---
 crates/oxc_allocator/src/arena.rs | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/crates/oxc_allocator/src/arena.rs b/crates/oxc_allocator/src/arena.rs
index aa2ec32ef..81459678c 100644
--- a/crates/oxc_allocator/src/arena.rs
+++ b/crates/oxc_allocator/src/arena.rs
@@ -124,7 +124,9 @@ impl<'alloc, T> Vec<'alloc, T> {
 
     #[inline]
     pub fn from_iter_in<I: IntoIterator<Item = T>>(iter: I, allocator: &'alloc Allocator) -> Self {
-        let mut vec = vec::Vec::new_in(&**allocator);
+        let iter = iter.into_iter();
+        let capacity = iter.size_hint().1.unwrap_or(0);
+        let mut vec = vec::Vec::with_capacity_in(capacity, &**allocator);
         vec.extend(iter);
         Self(vec)
     }