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use std::fmt;
fn foo() -> Box<impl fmt::Debug+?Sized> {
let x : Box<[u8]> = Box::new([0]);
x
}
fn bar() -> Box<impl fmt::Debug+?Sized> {
let y: Box<dyn fmt::Debug> = Box::new([0]);
y
}
fn main() {
let f = foo();
let b = bar();
// this is an `*mut [u8]` in practice
let f_raw : *mut _ = Box::into_raw(f);
// this is an `*mut fmt::Debug` in practice
let mut b_raw = Box::into_raw(b);
// ... and they should not be mixable
b_raw = f_raw as *mut _; //~ ERROR is invalid
}
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