Auto merge of #105917 - a1phyr:read_chain_more_impls, r=workingjubilee

Specialize some methods of `io::Chain`

This PR specializes the implementation of some methods of `io::Chain`, which could bring performance improvements when using it.

1 files changed, 11 insertions, 0 deletions

diff --git a/library/std/src/io/tests.rs b/library/std/src/io/tests.rs
index fd7e51688cd..5396f7f6e21 100644
--- a/library/std/src/io/tests.rs
+++ b/library/std/src/io/tests.rs
@@ -262,6 +262,17 @@ fn chain_bufread() {
 }
 
 #[test]
+fn chain_splitted_char() {
+    let chain = b"\xc3".chain(b"\xa9".as_slice());
+    assert_eq!(crate::io::read_to_string(chain).unwrap(), "é");
+
+    let mut chain = b"\xc3".chain(b"\xa9\n".as_slice());
+    let mut buf = String::new();
+    assert_eq!(chain.read_line(&mut buf).unwrap(), 3);
+    assert_eq!(buf, "é\n");
+}
+
+#[test]
 fn bufreader_size_hint() {
     let testdata = b"ABCDEFGHIJKL";
     let mut buf_reader = BufReader::new(&testdata[..]);