Vendor things

third-party/vendor/zerocopy-derive/tests/union_known_layout.rs

@@ -0,0 +1,65 @@
+// Copyright 2022 The Fuchsia Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#![allow(warnings)]
+
+#[macro_use]
+mod util;
+
+use std::{marker::PhantomData, option::IntoIter};
+
+use {static_assertions::assert_impl_all, zerocopy::KnownLayout};
+
+#[derive(Clone, Copy, KnownLayout)]
+union Zst {
+    a: (),
+}
+
+assert_impl_all!(Zst: KnownLayout);
+
+#[derive(KnownLayout)]
+union One {
+    a: bool,
+}
+
+assert_impl_all!(One: KnownLayout);
+
+#[derive(KnownLayout)]
+union Two {
+    a: bool,
+    b: Zst,
+}
+
+assert_impl_all!(Two: KnownLayout);
+
+#[derive(KnownLayout)]
+union TypeParams<'a, T: Copy, I: Iterator>
+where
+    I::Item: Copy,
+{
+    a: T,
+    c: I::Item,
+    d: u8,
+    e: PhantomData<&'a [u8]>,
+    f: PhantomData<&'static str>,
+    g: PhantomData<String>,
+}
+
+assert_impl_all!(TypeParams<'static, (), IntoIter<()>>: KnownLayout);
+
+// Deriving `KnownLayout` should work if the union has bounded parameters.
+
+#[derive(KnownLayout)]
+#[repr(C)]
+union WithParams<'a: 'b, 'b: 'a, const N: usize, T: 'a + 'b + KnownLayout>
+where
+    'a: 'b,
+    'b: 'a,
+    T: 'a + 'b + Copy + KnownLayout,
+{
+    a: [T; N],
+    b: PhantomData<&'a &'b ()>,
+}
+
+assert_impl_all!(WithParams<'static, 'static, 42, u8>: KnownLayout);