34 lines
692 B
Rust
34 lines
692 B
Rust
//@ run-pass
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// Checks that the Fn trait hierarchy rules permit
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// FnMut or FnOnce to be used where FnMut is implemented.
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#![feature(unboxed_closures, fn_traits)]
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struct S;
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impl FnMut<(i32,)> for S {
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extern "rust-call" fn call_mut(&mut self, (x,): (i32,)) -> i32 {
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x * x
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}
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}
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impl FnOnce<(i32,)> for S {
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type Output = i32;
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extern "rust-call" fn call_once(mut self, args: (i32,)) -> i32 { self.call_mut(args) }
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}
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fn call_it_mut<F:FnMut(i32)->i32>(f: &mut F, x: i32) -> i32 {
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f(x)
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}
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fn call_it_once<F:FnOnce(i32)->i32>(f: F, x: i32) -> i32 {
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f(x)
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}
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fn main() {
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let y = call_it_mut(&mut S, 22);
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let z = call_it_once(S, 22);
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assert_eq!(y, z);
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}
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