add regression test for #71805
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src/test/ui/const-generics/type-dependent/issue-71805.rs
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src/test/ui/const-generics/type-dependent/issue-71805.rs
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// run-pass
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#![feature(const_generics)]
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#![allow(incomplete_features)]
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use std::mem::MaybeUninit;
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trait CollectSlice<'a>: Iterator {
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fn inner_array<const N: usize>(&mut self) -> [Self::Item; N];
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fn collect_array<const N: usize>(&mut self) -> [Self::Item; N] {
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let result = self.inner_array();
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assert!(self.next().is_none());
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result
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}
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}
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impl<'a, I: ?Sized> CollectSlice<'a> for I
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where
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I: Iterator,
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{
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fn inner_array<const N: usize>(&mut self) -> [Self::Item; N] {
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let mut result: [MaybeUninit<Self::Item>; N] =
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unsafe { MaybeUninit::uninit().assume_init() };
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let mut count = 0;
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for (dest, item) in result.iter_mut().zip(self) {
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*dest = MaybeUninit::new(item);
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count += 1;
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}
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assert_eq!(N, count);
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let temp_ptr: *const [MaybeUninit<Self::Item>; N] = &result;
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unsafe { std::ptr::read(temp_ptr as *const [Self::Item; N]) }
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}
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}
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fn main() {
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let mut foos = [0u64; 9].iter().cloned();
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let _bar: [u64; 9] = foos.collect_array::<9_usize>();
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}
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