From f16d1fcb55d0b9c5d2a6c58e20c4352aa4a7c5fd Mon Sep 17 00:00:00 2001
From: binarycat <binarycat@envs.net>
Date: Mon, 25 Aug 2025 10:26:22 -0500
Subject: use size_hint in attrs_to_doc_fragments

---
 compiler/rustc_resolve/src/rustdoc.rs | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

(limited to 'compiler/rustc_resolve/src/rustdoc.rs')

diff --git a/compiler/rustc_resolve/src/rustdoc.rs b/compiler/rustc_resolve/src/rustdoc.rs
index 6450f63472c..f9f2f84bc50 100644
--- a/compiler/rustc_resolve/src/rustdoc.rs
+++ b/compiler/rustc_resolve/src/rustdoc.rs
@@ -207,8 +207,10 @@ pub fn attrs_to_doc_fragments<'a, A: AttributeExt + Clone + 'a>(
     attrs: impl Iterator<Item = (&'a A, Option<DefId>)>,
     doc_only: bool,
 ) -> (Vec<DocFragment>, ThinVec<A>) {
-    let mut doc_fragments = Vec::new();
-    let mut other_attrs = ThinVec::<A>::new();
+    let (min_size, max_size) = attrs.size_hint();
+    let size_hint = max_size.unwrap_or(min_size);
+    let mut doc_fragments = Vec::with_capacity(size_hint);
+    let mut other_attrs = ThinVec::<A>::with_capacity(if doc_only { 0 } else { size_hint });
     for (attr, item_id) in attrs {
         if let Some((doc_str, comment_kind)) = attr.doc_str_and_comment_kind() {
             let doc = beautify_doc_string(doc_str, comment_kind);
@@ -230,6 +232,9 @@ pub fn attrs_to_doc_fragments<'a, A: AttributeExt + Clone + 'a>(
         }
     }
 
+    doc_fragments.shrink_to_fit();
+    other_attrs.shrink_to_fit();
+
     unindent_doc_fragments(&mut doc_fragments);
 
     (doc_fragments, other_attrs)
-- 
cgit 1.4.1-3-g733a5