3 files changed, 3 insertions, 0 deletions
diff --git a/src/libstd/sys/unix/io.rs b/src/libstd/sys/unix/io.rs
index 72954ff20ef..bc854e772e1 100644
--- a/src/libstd/sys/unix/io.rs
+++ b/src/libstd/sys/unix/io.rs
@@ -29,6 +29,7 @@ impl<'a> IoSlice<'a> {
     }
 }
 
+#[repr(transparent)]
 pub struct IoSliceMut<'a> {
     vec: iovec,
     _p: PhantomData<&'a mut [u8]>,
diff --git a/src/libstd/sys/wasi/io.rs b/src/libstd/sys/wasi/io.rs
index cc8f1e16fa0..a5bddad708b 100644
--- a/src/libstd/sys/wasi/io.rs
+++ b/src/libstd/sys/wasi/io.rs
@@ -29,6 +29,7 @@ impl<'a> IoSlice<'a> {
     }
 }
 
+#[repr(transparent)]
 pub struct IoSliceMut<'a> {
     vec: __wasi_iovec_t,
     _p: PhantomData<&'a mut [u8]>,
diff --git a/src/libstd/sys/windows/io.rs b/src/libstd/sys/windows/io.rs
index c045a63e911..f0da2323f4f 100644
--- a/src/libstd/sys/windows/io.rs
+++ b/src/libstd/sys/windows/io.rs
@@ -29,6 +29,7 @@ impl<'a> IoSlice<'a> {
     }
 }
 
+#[repr(transparent)]
 pub struct IoSliceMut<'a> {
     vec: c::WSABUF,
     _p: PhantomData<&'a mut [u8]>,