diff --git a/src/process/terminalsource.rs b/src/process/terminalsource.rs
index 46b510c661..b0331b4b01 100644
--- a/src/process/terminalsource.rs
+++ b/src/process/terminalsource.rs
@@ -69,6 +69,16 @@ enum TerminalInner {
     TestWriter(TestWriter, ColorChoice),
 }
 
+impl TerminalInner {
+    fn as_write(&mut self) -> &mut dyn io::Write {
+        match self {
+            TerminalInner::StandardStream(s, _) => s,
+            #[cfg(feature = "test")]
+            TerminalInner::TestWriter(w, _) => w,
+        }
+    }
+}
+
 pub struct ColorableTerminalLocked {
     // Must drop the lock before the guard, as the guard borrows from inner.
     locked: TerminalInnerLocked,
@@ -83,6 +93,16 @@ enum TerminalInnerLocked {
     TestWriter(TestWriterLock<'static>),
 }
 
+impl TerminalInnerLocked {
+    fn as_write(&mut self) -> &mut dyn io::Write {
+        match self {
+            TerminalInnerLocked::StandardStream(s) => s,
+            #[cfg(feature = "test")]
+            TerminalInnerLocked::TestWriter(w) => w,
+        }
+    }
+}
+
 impl ColorableTerminal {
     /// A terminal that supports colorisation of a stream.
     /// If `RUSTUP_TERM_COLOR` is set to `always`, or if the stream is a tty and
@@ -202,37 +222,50 @@ pub enum Attr {
 
 impl io::Write for ColorableTerminal {
     fn write(&mut self, buf: &[u8]) -> std::result::Result<usize, io::Error> {
-        match self.inner.lock().unwrap().deref_mut() {
-            TerminalInner::StandardStream(s, _) => s.write(buf),
-            #[cfg(feature = "test")]
-            TerminalInner::TestWriter(w, _) => w.write(buf),
-        }
+        let mut locked = self.inner.lock().unwrap();
+        locked.deref_mut().as_write().write(buf)
+    }
+
+    fn write_vectored(&mut self, bufs: &[std::io::IoSlice<'_>]) -> std::io::Result<usize> {
+        let mut locked = self.inner.lock().unwrap();
+        locked.deref_mut().as_write().write_vectored(bufs)
     }
 
     fn flush(&mut self) -> std::result::Result<(), io::Error> {
-        match self.inner.lock().unwrap().deref_mut() {
-            TerminalInner::StandardStream(s, _) => s.flush(),
-            #[cfg(feature = "test")]
-            TerminalInner::TestWriter(w, _) => w.flush(),
-        }
+        let mut locked = self.inner.lock().unwrap();
+        locked.deref_mut().as_write().flush()
+    }
+
+    fn write_all(&mut self, buf: &[u8]) -> std::io::Result<()> {
+        let mut locked = self.inner.lock().unwrap();
+        locked.deref_mut().as_write().write_all(buf)
+    }
+
+    fn write_fmt(&mut self, args: std::fmt::Arguments<'_>) -> std::io::Result<()> {
+        let mut locked = self.inner.lock().unwrap();
+        locked.deref_mut().as_write().write_fmt(args)
     }
 }
 
 impl io::Write for ColorableTerminalLocked {
     fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
-        match &mut self.locked {
-            TerminalInnerLocked::StandardStream(s) => s.write(buf),
-            #[cfg(feature = "test")]
-            TerminalInnerLocked::TestWriter(w) => w.write(buf),
-        }
+        self.locked.as_write().write(buf)
+    }
+
+    fn write_vectored(&mut self, bufs: &[std::io::IoSlice<'_>]) -> std::io::Result<usize> {
+        self.locked.as_write().write_vectored(bufs)
     }
 
     fn flush(&mut self) -> io::Result<()> {
-        match &mut self.locked {
-            TerminalInnerLocked::StandardStream(s) => s.flush(),
-            #[cfg(feature = "test")]
-            TerminalInnerLocked::TestWriter(w) => w.flush(),
-        }
+        self.locked.as_write().flush()
+    }
+
+    fn write_all(&mut self, buf: &[u8]) -> std::io::Result<()> {
+        self.locked.as_write().write_all(buf)
+    }
+
+    fn write_fmt(&mut self, args: std::fmt::Arguments<'_>) -> std::io::Result<()> {
+        self.locked.as_write().write_fmt(args)
     }
 }