mirror of https://github.com/rust-lang/rust
51 lines
1.2 KiB
Rust
51 lines
1.2 KiB
Rust
//@ run-pass
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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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