Auto merge of #130803 - cuviper:file-buffered, r=joshtriplett

Add `File` constructors that return files wrapped with a buffer

In addition to the light convenience, these are intended to raise visibility that buffering is something you should consider when opening a file, since unbuffered I/O is a common performance footgun to Rust newcomers.

ACP: https://github.com/rust-lang/libs-team/issues/446
Tracking Issue: #130804

2 files changed, 2 insertions, 2 deletions

diff --git a/compiler/rustc_metadata/src/fs.rs b/compiler/rustc_metadata/src/fs.rs
index a58f3c6b5ca..4450d050c8e 100644
--- a/compiler/rustc_metadata/src/fs.rs
+++ b/compiler/rustc_metadata/src/fs.rs
@@ -128,8 +128,7 @@ pub fn non_durable_rename(src: &Path, dst: &Path) -> std::io::Result<()> {
 }
 
 pub fn copy_to_stdout(from: &Path) -> io::Result<()> {
-    let file = fs::File::open(from)?;
-    let mut reader = io::BufReader::new(file);
+    let mut reader = fs::File::open_buffered(from)?;
     let mut stdout = io::stdout();
     io::copy(&mut reader, &mut stdout)?;
     Ok(())
diff --git a/compiler/rustc_metadata/src/lib.rs b/compiler/rustc_metadata/src/lib.rs
index 1759ea7d441..10f2087d1e6 100644
--- a/compiler/rustc_metadata/src/lib.rs
+++ b/compiler/rustc_metadata/src/lib.rs
@@ -8,6 +8,7 @@
 #![feature(decl_macro)]
 #![feature(error_iter)]
 #![feature(extract_if)]
+#![feature(file_buffered)]
 #![feature(if_let_guard)]
 #![feature(iter_from_coroutine)]
 #![feature(let_chains)]