1 files changed, 95 insertions, 0 deletions
diff --git a/src/test/ui/layout/zero-sized-array-union.rs b/src/test/ui/layout/zero-sized-array-union.rs
new file mode 100644
index 000000000..1a662ba44
--- /dev/null
+++ b/src/test/ui/layout/zero-sized-array-union.rs
@@ -0,0 +1,95 @@
+#![feature(rustc_attrs)]
+
+// Various tests around the behavior of zero-sized arrays and
+// unions. This matches the behavior of modern C compilers, though
+// older compilers (and sometimes clang) treat `T[0]` as a "flexible
+// array member". See more
+// details in #56877.
+
+#[derive(Copy, Clone)]
+#[repr(C)]
+struct Empty { }
+
+#[derive(Copy, Clone)]
+#[repr(C)]
+struct Empty2 {
+    e: Empty
+}
+
+#[derive(Copy, Clone)]
+#[repr(C)]
+struct Empty3 {
+    z: [f32; 0],
+}
+
+#[derive(Copy, Clone)]
+#[repr(C)]
+struct Empty4 {
+    e: Empty3
+}
+
+#[repr(C)]
+union U1 {
+    s: Empty
+}
+
+#[repr(C)]
+union U2 {
+    s: Empty2
+}
+
+#[repr(C)]
+union U3 {
+    s: Empty3
+}
+
+#[repr(C)]
+union U4 {
+    s: Empty4
+}
+
+#[repr(C)]
+struct Baz1 {
+    x: f32,
+    y: f32,
+    u: U1,
+}
+
+#[rustc_layout(homogeneous_aggregate)]
+type TestBaz1 = Baz1;
+//~^ ERROR homogeneous_aggregate: Ok(Homogeneous
+
+#[repr(C)]
+struct Baz2 {
+    x: f32,
+    y: f32,
+    u: U2,
+}
+
+#[rustc_layout(homogeneous_aggregate)]
+type TestBaz2 = Baz2;
+//~^ ERROR homogeneous_aggregate: Ok(Homogeneous
+
+#[repr(C)]
+struct Baz3 {
+    x: f32,
+    y: f32,
+    u: U3,
+}
+
+#[rustc_layout(homogeneous_aggregate)]
+type TestBaz3 = Baz3;
+//~^ ERROR homogeneous_aggregate: Ok(Homogeneous
+
+#[repr(C)]
+struct Baz4 {
+    x: f32,
+    y: f32,
+    u: U4,
+}
+
+#[rustc_layout(homogeneous_aggregate)]
+type TestBaz4 = Baz4;
+//~^ ERROR homogeneous_aggregate: Ok(Homogeneous
+
+fn main() { }