32 lines
770 B
Rust
32 lines
770 B
Rust
//@ run-pass
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// Checks that higher-ranked extern fn pointers implement the full range of Fn traits.
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fn square(x: &isize) -> isize { (*x) * (*x) }
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fn call_it<F:Fn(&isize)->isize>(f: &F, x: isize) -> isize {
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(*f)(&x)
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}
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fn call_it_boxed(f: &dyn Fn(&isize) -> isize, x: isize) -> isize {
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f(&x)
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}
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fn call_it_mut<F:FnMut(&isize)->isize>(f: &mut F, x: isize) -> isize {
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(*f)(&x)
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}
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fn call_it_once<F:FnOnce(&isize)->isize>(f: F, x: isize) -> isize {
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f(&x)
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}
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fn main() {
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let x = call_it(&square, 22);
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let x1 = call_it_boxed(&square, 22);
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let y = call_it_mut(&mut square, 22);
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let z = call_it_once(square, 22);
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assert_eq!(x, square(&22));
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assert_eq!(x1, square(&22));
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assert_eq!(y, square(&22));
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assert_eq!(z, square(&22));
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}
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