mirror of https://github.com/rust-lang/rust
68 lines
1.8 KiB
Rust
68 lines
1.8 KiB
Rust
//@ run-pass
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#![allow(dead_code)]
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#![allow(deprecated)]
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#![allow(non_snake_case)]
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use std::mem;
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enum Tag<A,B> {
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VarA(A),
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VarB(B),
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}
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struct Rec<A,B> {
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chA: u8,
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tA: Tag<A,B>,
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chB: u8,
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tB: Tag<A,B>,
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}
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fn mk_rec<A,B>(a: A, b: B) -> Rec<A,B> {
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Rec { chA:0, tA:Tag::VarA(a), chB:1, tB:Tag::VarB(b) }
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}
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fn is_aligned<A>(amnt: usize, u: &A) -> bool {
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let p: usize = unsafe { mem::transmute(u) };
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return (p & (amnt-1)) == 0;
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}
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fn variant_data_is_aligned<A,B>(amnt: usize, u: &Tag<A,B>) -> bool {
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match u {
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&Tag::VarA(ref a) => is_aligned(amnt, a),
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&Tag::VarB(ref b) => is_aligned(amnt, b)
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}
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}
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pub fn main() {
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let u64_align = std::mem::min_align_of::<u64>();
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let x = mk_rec(22u64, 23u64);
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assert!(is_aligned(u64_align, &x.tA));
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assert!(variant_data_is_aligned(u64_align, &x.tA));
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assert!(is_aligned(u64_align, &x.tB));
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assert!(variant_data_is_aligned(u64_align, &x.tB));
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let x = mk_rec(22u64, 23u32);
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assert!(is_aligned(u64_align, &x.tA));
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assert!(variant_data_is_aligned(u64_align, &x.tA));
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assert!(is_aligned(u64_align, &x.tB));
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assert!(variant_data_is_aligned(4, &x.tB));
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let x = mk_rec(22u32, 23u64);
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assert!(is_aligned(u64_align, &x.tA));
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assert!(variant_data_is_aligned(4, &x.tA));
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assert!(is_aligned(u64_align, &x.tB));
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assert!(variant_data_is_aligned(u64_align, &x.tB));
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let x = mk_rec(22u32, 23u32);
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assert!(is_aligned(4, &x.tA));
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assert!(variant_data_is_aligned(4, &x.tA));
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assert!(is_aligned(4, &x.tB));
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assert!(variant_data_is_aligned(4, &x.tB));
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let x = mk_rec(22f64, 23f64);
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assert!(is_aligned(u64_align, &x.tA));
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assert!(variant_data_is_aligned(u64_align, &x.tA));
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assert!(is_aligned(u64_align, &x.tB));
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assert!(variant_data_is_aligned(u64_align, &x.tB));
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}
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