1 files changed, 12 insertions, 11 deletions
diff --git a/library/std/src/io/tests.rs b/library/std/src/io/tests.rs
index f357f33ec..f4a886d88 100644
--- a/library/std/src/io/tests.rs
+++ b/library/std/src/io/tests.rs
@@ -1,4 +1,4 @@
-use super::{repeat, Cursor, ReadBuf, SeekFrom};
+use super::{repeat, BorrowedBuf, Cursor, SeekFrom};
 use crate::cmp::{self, min};
 use crate::io::{self, IoSlice, IoSliceMut};
 use crate::io::{BufRead, BufReader, Read, Seek, Write};
@@ -94,7 +94,7 @@ fn read_to_end() {
     assert_eq!(c.read_to_end(&mut v).unwrap(), 1);
     assert_eq!(v, b"1");
 
-    let cap = 1024 * 1024;
+    let cap = if cfg!(miri) { 1024 } else { 1024 * 1024 };
     let data = (0..cap).map(|i| (i / 3) as u8).collect::<Vec<_>>();
     let mut v = Vec::new();
     let (a, b) = data.split_at(data.len() / 2);
@@ -159,24 +159,24 @@ fn read_exact_slice() {
 
 #[test]
 fn read_buf_exact() {
-    let mut buf = [0; 4];
-    let mut buf = ReadBuf::new(&mut buf);
+    let buf: &mut [_] = &mut [0; 4];
+    let mut buf: BorrowedBuf<'_> = buf.into();
 
     let mut c = Cursor::new(&b""[..]);
-    assert_eq!(c.read_buf_exact(&mut buf).unwrap_err().kind(), io::ErrorKind::UnexpectedEof);
+    assert_eq!(c.read_buf_exact(buf.unfilled()).unwrap_err().kind(), io::ErrorKind::UnexpectedEof);
 
     let mut c = Cursor::new(&b"123456789"[..]);
-    c.read_buf_exact(&mut buf).unwrap();
+    c.read_buf_exact(buf.unfilled()).unwrap();
     assert_eq!(buf.filled(), b"1234");
 
     buf.clear();
 
-    c.read_buf_exact(&mut buf).unwrap();
+    c.read_buf_exact(buf.unfilled()).unwrap();
     assert_eq!(buf.filled(), b"5678");
 
     buf.clear();
 
-    assert_eq!(c.read_buf_exact(&mut buf).unwrap_err().kind(), io::ErrorKind::UnexpectedEof);
+    assert_eq!(c.read_buf_exact(buf.unfilled()).unwrap_err().kind(), io::ErrorKind::UnexpectedEof);
 }
 
 #[test]
@@ -309,6 +309,7 @@ fn chain_zero_length_read_is_not_eof() {
 
 #[bench]
 #[cfg_attr(target_os = "emscripten", ignore)]
+#[cfg_attr(miri, ignore)] // Miri isn't fast...
 fn bench_read_to_end(b: &mut test::Bencher) {
     b.iter(|| {
         let mut lr = repeat(1).take(10000000);
@@ -614,10 +615,10 @@ fn bench_take_read(b: &mut test::Bencher) {
 #[bench]
 fn bench_take_read_buf(b: &mut test::Bencher) {
     b.iter(|| {
-        let mut buf = [MaybeUninit::uninit(); 64];
+        let buf: &mut [_] = &mut [MaybeUninit::uninit(); 64];
 
-        let mut rbuf = ReadBuf::uninit(&mut buf);
+        let mut buf: BorrowedBuf<'_> = buf.into();
 
-        [255; 128].take(64).read_buf(&mut rbuf).unwrap();
+        [255; 128].take(64).read_buf(buf.unfilled()).unwrap();
     });
 }