mirror of https://github.com/rust-lang/rust
41 lines
1.0 KiB
Rust
41 lines
1.0 KiB
Rust
#![allow(dead_code)]
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#![allow(dropping_copy_types)]
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// "guessing" in trait selection can affect `copy_or_move`. Check that this
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// is correctly handled. I am not sure what is the "correct" behaviour,
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// but we should at least not ICE.
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use std::mem;
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struct U([u8; 1337]);
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struct S<'a,T:'a>(&'a T);
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impl<'a, T> Clone for S<'a, T> { fn clone(&self) -> Self { S(self.0) } }
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/// This impl triggers inference "guessing" - S<_>: Copy => _ = U
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impl<'a> Copy for S<'a, Option<U>> {}
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fn assert_impls_fn<R,T: Fn()->R>(_: &T){}
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fn main() {
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let n = None;
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//~^ ERROR type annotations needed for `Option<_>`
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let e = S(&n);
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let f = || {
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// S being copy is critical for this to work
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drop(e);
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mem::size_of_val(e.0)
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};
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assert_impls_fn(&f);
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assert_eq!(f(), 1337+1);
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assert_eq!((|| {
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// S being Copy is not critical here, but
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// we check it anyway.
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let n = None;
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let e = S(&n);
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let ret = mem::size_of_val(e.0);
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drop(e);
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ret
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})(), 1337+1);
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}
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