Rollup merge of rust-lang#76275 - FedericoPonzi:immutable-write-impl-73836, r=dtolnay

Implementation of Write for some immutable ref structs

Fixes  rust-lang#73836

Author: ecstatic-morse

library/std/src/io/stdio.rs

@@ -586,6 +586,32 @@ impl fmt::Debug for Stdout {
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl Write for Stdout {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        (&*self).write(buf)
+    }
+    fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> io::Result<usize> {
+        (&*self).write_vectored(bufs)
+    }
+    #[inline]
+    fn is_write_vectored(&self) -> bool {
+        io::Write::is_write_vectored(&&*self)
+    }
+    fn flush(&mut self) -> io::Result<()> {
+        (&*self).flush()
+    }
+    fn write_all(&mut self, buf: &[u8]) -> io::Result<()> {
+        (&*self).write_all(buf)
+    }
+    fn write_all_vectored(&mut self, bufs: &mut [IoSlice<'_>]) -> io::Result<()> {
+        (&*self).write_all_vectored(bufs)
+    }
+    fn write_fmt(&mut self, args: fmt::Arguments<'_>) -> io::Result<()> {
+        (&*self).write_fmt(args)
+    }
+}
+
+#[stable(feature = "write_mt", since = "1.48.0")]
+impl Write for &Stdout {
     fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
         self.lock().write(buf)
     }
@@ -609,6 +635,7 @@ impl Write for Stdout {
         self.lock().write_fmt(args)
     }
 }
+
 #[stable(feature = "rust1", since = "1.0.0")]
 impl Write for StdoutLock<'_> {
     fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
@@ -762,6 +789,32 @@ impl fmt::Debug for Stderr {
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl Write for Stderr {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        (&*self).write(buf)
+    }
+    fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> io::Result<usize> {
+        (&*self).write_vectored(bufs)
+    }
+    #[inline]
+    fn is_write_vectored(&self) -> bool {
+        io::Write::is_write_vectored(&&*self)
+    }
+    fn flush(&mut self) -> io::Result<()> {
+        (&*self).flush()
+    }
+    fn write_all(&mut self, buf: &[u8]) -> io::Result<()> {
+        (&*self).write_all(buf)
+    }
+    fn write_all_vectored(&mut self, bufs: &mut [IoSlice<'_>]) -> io::Result<()> {
+        (&*self).write_all_vectored(bufs)
+    }
+    fn write_fmt(&mut self, args: fmt::Arguments<'_>) -> io::Result<()> {
+        (&*self).write_fmt(args)
+    }
+}
+
+#[stable(feature = "write_mt", since = "1.48.0")]
+impl Write for &Stderr {
     fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
         self.lock().write(buf)
     }
@@ -785,6 +838,7 @@ impl Write for Stderr {
         self.lock().write_fmt(args)
     }
 }
+
 #[stable(feature = "rust1", since = "1.0.0")]
 impl Write for StderrLock<'_> {
     fn write(&mut self, buf: &[u8]) -> io::Result<usize> {

library/std/src/io/util.rs

@@ -254,6 +254,30 @@ impl Write for Sink {
     }
 }
 
+#[stable(feature = "write_mt", since = "1.48.0")]
+impl Write for &Sink {
+    #[inline]
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        Ok(buf.len())
+    }
+
+    #[inline]
+    fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> io::Result<usize> {
+        let total_len = bufs.iter().map(|b| b.len()).sum();
+        Ok(total_len)
+    }
+
+    #[inline]
+    fn is_write_vectored(&self) -> bool {
+        true
+    }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> {
+        Ok(())
+    }
+}
+
 #[stable(feature = "std_debug", since = "1.16.0")]
 impl fmt::Debug for Sink {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {

library/std/src/process.rs

@@ -249,6 +249,25 @@ pub struct ChildStdin {
 
 #[stable(feature = "process", since = "1.0.0")]
 impl Write for ChildStdin {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        (&*self).write(buf)
+    }
+
+    fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> io::Result<usize> {
+        (&*self).write_vectored(bufs)
+    }
+
+    fn is_write_vectored(&self) -> bool {
+        io::Write::is_write_vectored(&&*self)
+    }
+
+    fn flush(&mut self) -> io::Result<()> {
+        (&*self).flush()
+    }
+}
+
+#[stable(feature = "write_mt", since = "1.48.0")]
+impl Write for &ChildStdin {
     fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
         self.inner.write(buf)
     }