17 lines
656 B
Rust
17 lines
656 B
Rust
// We *can* have aliasing &RefCell<T> and &mut T, but we cannot read through the former.
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// Else we couldn't optimize based on the assumption that `xref` below is truly unique.
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use std::cell::RefCell;
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use std::{mem, ptr};
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fn main() {
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let rc = RefCell::new(0);
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let mut refmut = rc.borrow_mut();
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let xref: &mut i32 = &mut *refmut;
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let xshr = &rc; // creating this is okay
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let _val = *xref; // we can even still use our mutable reference
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mem::forget(unsafe { ptr::read(xshr) }); // but after reading through the shared ref
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let _val = *xref; // the mutable one is dead and gone
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//~^ ERROR does not exist on the borrow stack
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}
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