diff --git a/library/std/src/io/buffered/linewritershim.rs b/library/std/src/io/buffered/linewritershim.rs
index a80d08db8692..d0c859d2e0c8 100644
--- a/library/std/src/io/buffered/linewritershim.rs
+++ b/library/std/src/io/buffered/linewritershim.rs
@@ -20,6 +20,12 @@ impl<'a, W: Write> LineWriterShim<'a, W> {
         Self { buffer }
     }
 
+    /// Get a reference to the inner writer (that is, the writer
+    /// wrapped by the BufWriter).
+    fn inner(&self) -> &W {
+        self.buffer.get_ref()
+    }
+
     /// Get a mutable reference to the inner writer (that is, the writer
     /// wrapped by the BufWriter). Be careful with this writer, as writes to
     /// it will bypass the buffer.
@@ -227,7 +233,7 @@ impl<'a, W: Write> Write for LineWriterShim<'a, W> {
     }
 
     fn is_write_vectored(&self) -> bool {
-        self.buffer.is_write_vectored()
+        self.inner().is_write_vectored()
     }
 
     /// Write some data into this BufReader with line buffering. This means