tests: Add a test for alignas(double).

Author: emilio

tests/expectations/tests/repr-align.rs

@@ -33,3 +33,34 @@ fn bindgen_test_layout_a() {
         concat!("Offset of field: ", stringify!(a), "::", stringify!(c))
     );
 }
+#[repr(C)]
+#[repr(align(8))]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct b {
+    pub b: ::std::os::raw::c_int,
+    pub c: ::std::os::raw::c_int,
+    pub __bindgen_align: [u64; 0usize],
+}
+#[test]
+fn bindgen_test_layout_b() {
+    assert_eq!(
+        ::std::mem::size_of::<b>(),
+        8usize,
+        concat!("Size of: ", stringify!(b))
+    );
+    assert_eq!(
+        ::std::mem::align_of::<b>(),
+        8usize,
+        concat!("Alignment of ", stringify!(b))
+    );
+    assert_eq!(
+        unsafe { &(*(::std::ptr::null::<b>())).b as *const _ as usize },
+        0usize,
+        concat!("Offset of field: ", stringify!(b), "::", stringify!(b))
+    );
+    assert_eq!(
+        unsafe { &(*(::std::ptr::null::<b>())).c as *const _ as usize },
+        4usize,
+        concat!("Offset of field: ", stringify!(b), "::", stringify!(c))
+    );
+}

tests/headers/repr-align.hpp

@@ -4,3 +4,8 @@ struct alignas(8) a {
   int b;
   int c;
 };
+
+struct alignas(double) b {
+  int b;
+  int c;
+};