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, 1 deletions

diff --git a/compiler/rustc_mir_transform/src/dump_mir.rs b/compiler/rustc_mir_transform/src/dump_mir.rs
index d7c47360419..5dd84975b88 100644
--- a/compiler/rustc_mir_transform/src/dump_mir.rs
+++ b/compiler/rustc_mir_transform/src/dump_mir.rs
@@ -24,7 +24,7 @@ pub fn emit_mir(tcx: TyCtxt<'_>) -> io::Result<()> {
             write_mir_pretty(tcx, None, &mut f)?;
         }
         OutFileName::Real(path) => {
-            let mut f = io::BufWriter::new(File::create(&path)?);
+            let mut f = File::create_buffered(&path)?;
             write_mir_pretty(tcx, None, &mut f)?;
             if tcx.sess.opts.json_artifact_notifications {
                 tcx.dcx().emit_artifact_notification(&path, "mir");
diff --git a/compiler/rustc_mir_transform/src/lib.rs b/compiler/rustc_mir_transform/src/lib.rs
index 56268c1d201..4c090665992 100644
--- a/compiler/rustc_mir_transform/src/lib.rs
+++ b/compiler/rustc_mir_transform/src/lib.rs
@@ -3,6 +3,7 @@
 #![feature(box_patterns)]
 #![feature(const_type_name)]
 #![feature(cow_is_borrowed)]
+#![feature(file_buffered)]
 #![feature(if_let_guard)]
 #![feature(impl_trait_in_assoc_type)]
 #![feature(let_chains)]