60 lines
1.6 KiB
Rust
60 lines
1.6 KiB
Rust
// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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// Test that we will do various size optimizations to enum layout, but
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// *not* if `#[repr(u8)]` or `#[repr(C)]` is passed. See also #40029.
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#![allow(dead_code)]
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use std::mem;
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enum Nullable<T> {
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Alive(T),
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Dropped,
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}
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#[repr(u8)]
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enum NullableU8<T> {
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Alive(T),
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Dropped,
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}
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#[repr(C)]
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enum NullableC<T> {
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Alive(T),
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Dropped,
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}
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struct StructNewtype<T>(T);
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#[repr(C)]
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struct StructNewtypeC<T>(T);
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enum EnumNewtype<T> { Variant(T) }
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#[repr(u8)]
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enum EnumNewtypeU8<T> { Variant(T) }
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#[repr(C)]
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enum EnumNewtypeC<T> { Variant(T) }
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fn main() {
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assert!(mem::size_of::<Box<i32>>() == mem::size_of::<Nullable<Box<i32>>>());
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assert!(mem::size_of::<Box<i32>>() < mem::size_of::<NullableU8<Box<i32>>>());
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assert!(mem::size_of::<Box<i32>>() < mem::size_of::<NullableC<Box<i32>>>());
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assert!(mem::size_of::<i32>() == mem::size_of::<StructNewtype<i32>>());
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assert!(mem::size_of::<i32>() == mem::size_of::<StructNewtypeC<i32>>());
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assert!(mem::size_of::<i32>() == mem::size_of::<EnumNewtype<i32>>());
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assert!(mem::size_of::<i32>() < mem::size_of::<EnumNewtypeU8<i32>>());
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assert!(mem::size_of::<i32>() < mem::size_of::<EnumNewtypeC<i32>>());
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}
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