Clarify semantics of #[repr(align(x))] on enums

diff --git a/src/doc/unstable-book/src/language-features/repr-align-enum.md b/src/doc/unstable-book/src/language-features/repr-align-enum.md
index 1fd9bd20f3f0d928f3ac3776b56bcabd0e9cebe4..415c6ebe8b4bcfe7e45026f4e0dda575da807bcb 100644 (file)
--- a/src/doc/unstable-book/src/language-features/repr-align-enum.md
+++ b/src/doc/unstable-book/src/language-features/repr-align-enum.md
@@ -24,3 +24,19 @@ fn main() {
     assert_eq!(std::mem::align_of::<Aligned>(), 8);
 }
 ```
+
+This is equivalent to using an aligned wrapper struct everywhere:
+
+```rust
+#[repr(align(8))]
+struct Aligned(Unaligned);
+
+enum Unaligned {
+    Foo,
+    Bar { value: u32 },
+}
+
+fn main() {
+    assert_eq!(std::mem::align_of::<Aligned>(), 8);
+}
+```