27 lines
573 B
Rust
27 lines
573 B
Rust
use core::mem::size_of;
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use std::boxed::ThinBox;
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#[test]
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fn want_niche_optimization() {
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fn uses_niche<T: ?Sized>() -> bool {
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size_of::<*const ()>() == size_of::<Option<ThinBox<T>>>()
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}
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trait Tr {}
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assert!(uses_niche::<dyn Tr>());
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assert!(uses_niche::<[i32]>());
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assert!(uses_niche::<i32>());
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}
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#[test]
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fn want_thin() {
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fn is_thin<T: ?Sized>() -> bool {
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size_of::<*const ()>() == size_of::<ThinBox<T>>()
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}
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trait Tr {}
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assert!(is_thin::<dyn Tr>());
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assert!(is_thin::<[i32]>());
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assert!(is_thin::<i32>());
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}
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