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_middle/src/lib.rs b/compiler/rustc_middle/src/lib.rs
index 23cd247e884..a32b19b067a 100644
--- a/compiler/rustc_middle/src/lib.rs
+++ b/compiler/rustc_middle/src/lib.rs
@@ -45,6 +45,7 @@
 #![feature(discriminant_kind)]
 #![feature(extern_types)]
 #![feature(extract_if)]
+#![feature(file_buffered)]
 #![feature(if_let_guard)]
 #![feature(intra_doc_pointers)]
 #![feature(iter_from_coroutine)]
diff --git a/compiler/rustc_middle/src/mir/pretty.rs b/compiler/rustc_middle/src/mir/pretty.rs
index 119aed1106d..48789565218 100644
--- a/compiler/rustc_middle/src/mir/pretty.rs
+++ b/compiler/rustc_middle/src/mir/pretty.rs
@@ -277,9 +277,9 @@ pub fn create_dump_file<'tcx>(
             )
         })?;
     }
-    Ok(io::BufWriter::new(fs::File::create(&file_path).map_err(|e| {
+    Ok(fs::File::create_buffered(&file_path).map_err(|e| {
         io::Error::new(e.kind(), format!("IO error creating MIR dump file: {file_path:?}; {e}"))
-    })?))
+    })?)
 }
 
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