Vendor things

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

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+// Copyright 2019 The Fuchsia Authors
+//
+// Licensed under a BSD-style license <LICENSE-BSD>, Apache License, Version 2.0
+// <LICENSE-APACHE or https://www.apache.org/licenses/LICENSE-2.0>, or the MIT
+// license <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your option.
+// This file may not be copied, modified, or distributed except according to
+// those terms.
+
+#![allow(warnings)]
+
+mod util;
+
+use std::{marker::PhantomData, option::IntoIter};
+
+use {static_assertions::assert_impl_all, zerocopy::Unaligned};
+
+use crate::util::AU16;
+
+// A struct is `Unaligned` if:
+// - `repr(align)` is no more than 1 and either
+//   - `repr(C)` or `repr(transparent)` and
+//     - all fields Unaligned
+//   - `repr(packed)`
+
+#[derive(Unaligned)]
+#[repr(C)]
+struct Foo {
+    a: u8,
+}
+
+assert_impl_all!(Foo: Unaligned);
+
+#[derive(Unaligned)]
+#[repr(transparent)]
+struct Bar {
+    a: u8,
+}
+
+assert_impl_all!(Bar: Unaligned);
+
+#[derive(Unaligned)]
+#[repr(packed)]
+struct Baz {
+    // NOTE: The `u16` type is not guaranteed to have alignment 2, although it
+    // does on many platforms. However, to fix this would require a custom type
+    // with a `#[repr(align(2))]` attribute, and `#[repr(packed)]` types are not
+    // allowed to transitively contain `#[repr(align(...))]` types. Thus, we
+    // have no choice but to use `u16` here. Luckily, these tests run in CI on
+    // platforms on which `u16` has alignment 2, so this isn't that big of a
+    // deal.
+    a: u16,
+}
+
+assert_impl_all!(Baz: Unaligned);
+
+#[derive(Unaligned)]
+#[repr(C, align(1))]
+struct FooAlign {
+    a: u8,
+}
+
+assert_impl_all!(FooAlign: Unaligned);
+
+#[derive(Unaligned)]
+#[repr(transparent)]
+struct Unsized {
+    a: [u8],
+}
+
+assert_impl_all!(Unsized: Unaligned);
+
+#[derive(Unaligned)]
+#[repr(C)]
+struct TypeParams<'a, T: ?Sized, I: Iterator> {
+    a: I::Item,
+    b: u8,
+    c: PhantomData<&'a [u8]>,
+    d: PhantomData<&'static str>,
+    e: PhantomData<String>,
+    f: T,
+}
+
+assert_impl_all!(TypeParams<'static, (), IntoIter<()>>: Unaligned);
+assert_impl_all!(TypeParams<'static, u8, IntoIter<()>>: Unaligned);
+assert_impl_all!(TypeParams<'static, [u8], IntoIter<()>>: Unaligned);
+
+// Deriving `Unaligned` should work if the struct has bounded parameters.
+
+#[derive(Unaligned)]
+#[repr(transparent)]
+struct WithParams<'a: 'b, 'b: 'a, const N: usize, T: 'a + 'b + Unaligned>(
+    [T; N],
+    PhantomData<&'a &'b ()>,
+)
+where
+    'a: 'b,
+    'b: 'a,
+    T: 'a + 'b + Unaligned;
+
+assert_impl_all!(WithParams<'static, 'static, 42, u8>: Unaligned);