2 files changed, 71 insertions, 0 deletions
diff --git a/tests/expectations/tests/explicit-padding.rs b/tests/expectations/tests/explicit-padding.rs
index e395e5d2..3c429756 100644
--- a/tests/expectations/tests/explicit-padding.rs
+++ b/tests/expectations/tests/explicit-padding.rs
@@ -63,3 +63,68 @@ fn bindgen_test_layout_pad_me() {
         )
     );
 }
+#[repr(C)]
+#[derive(Copy, Clone)]
+pub union dont_pad_me {
+    pub first: u8,
+    pub second: u32,
+    pub third: u16,
+}
+#[test]
+fn bindgen_test_layout_dont_pad_me() {
+    assert_eq!(
+        ::std::mem::size_of::<dont_pad_me>(),
+        4usize,
+        concat!("Size of: ", stringify!(dont_pad_me))
+    );
+    assert_eq!(
+        ::std::mem::align_of::<dont_pad_me>(),
+        4usize,
+        concat!("Alignment of ", stringify!(dont_pad_me))
+    );
+    assert_eq!(
+        unsafe {
+            &(*(::std::ptr::null::<dont_pad_me>())).first as *const _ as usize
+        },
+        0usize,
+        concat!(
+            "Offset of field: ",
+            stringify!(dont_pad_me),
+            "::",
+            stringify!(first)
+        )
+    );
+    assert_eq!(
+        unsafe {
+            &(*(::std::ptr::null::<dont_pad_me>())).second as *const _ as usize
+        },
+        0usize,
+        concat!(
+            "Offset of field: ",
+            stringify!(dont_pad_me),
+            "::",
+            stringify!(second)
+        )
+    );
+    assert_eq!(
+        unsafe {
+            &(*(::std::ptr::null::<dont_pad_me>())).third as *const _ as usize
+        },
+        0usize,
+        concat!(
+            "Offset of field: ",
+            stringify!(dont_pad_me),
+            "::",
+            stringify!(third)
+        )
+    );
+}
+impl Default for dont_pad_me {
+    fn default() -> Self {
+        let mut s = ::std::mem::MaybeUninit::<Self>::uninit();
+        unsafe {
+            ::std::ptr::write_bytes(s.as_mut_ptr(), 0, 1);
+            s.assume_init()
+        }
+    }
+}
diff --git a/tests/headers/explicit-padding.h b/tests/headers/explicit-padding.h
index d228961d..4abaafba 100644
--- a/tests/headers/explicit-padding.h
+++ b/tests/headers/explicit-padding.h
@@ -9,3 +9,9 @@ struct pad_me {
         uint32_t second;
         uint16_t third;
 };
+
+union dont_pad_me {
+        uint8_t first;
+        uint32_t second;
+        uint16_t third;
+};