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, 3 insertions, 2 deletions

diff --git a/compiler/rustc_borrowck/src/facts.rs b/compiler/rustc_borrowck/src/facts.rs
index 713452796c6..ef8e757a547 100644
--- a/compiler/rustc_borrowck/src/facts.rs
+++ b/compiler/rustc_borrowck/src/facts.rs
@@ -1,7 +1,7 @@
 use std::error::Error;
 use std::fmt::Debug;
 use std::fs::{self, File};
-use std::io::{BufWriter, Write};
+use std::io::Write;
 use std::path::Path;
 
 use polonius_engine::{AllFacts as PoloniusFacts, Atom};
@@ -127,7 +127,7 @@ impl<'w> FactWriter<'w> {
         T: FactRow,
     {
         let file = &self.dir.join(file_name);
-        let mut file = BufWriter::new(File::create(file)?);
+        let mut file = File::create_buffered(file)?;
         for row in rows {
             row.write(&mut file, self.location_table)?;
         }
diff --git a/compiler/rustc_borrowck/src/lib.rs b/compiler/rustc_borrowck/src/lib.rs
index 733fabe557e..a11eca0b9c7 100644
--- a/compiler/rustc_borrowck/src/lib.rs
+++ b/compiler/rustc_borrowck/src/lib.rs
@@ -6,6 +6,7 @@
 #![feature(assert_matches)]
 #![feature(box_patterns)]
 #![feature(control_flow_enum)]
+#![feature(file_buffered)]
 #![feature(let_chains)]
 #![feature(never_type)]
 #![feature(rustc_attrs)]