54 lines
1.1 KiB
Rust
54 lines
1.1 KiB
Rust
fn simple() -> i32 {
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let y = 10;
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let f = |x| x + y;
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f(2)
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}
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fn crazy_closure() -> (i32, i32, i32) {
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fn inner<T: Copy>(t: T) -> (i32, T, T) {
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struct NonCopy;
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let x = NonCopy;
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let a = 2;
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let b = 40;
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let f = move |y, z, asdf| {
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drop(x);
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(a + b + y + z, asdf, t)
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};
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f(a, b, t)
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}
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inner(10)
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}
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fn closure_arg_adjustment_problem() -> i64 {
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fn once<F: FnOnce(i64)>(f: F) { f(2); }
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let mut y = 1;
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{
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let f = |x| y += x;
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once(f);
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}
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y
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}
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fn fn_once_closure_with_multiple_args() -> i64 {
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fn once<F: FnOnce(i64, i64) -> i64>(f: F) -> i64 { f(2, 3) }
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let y = 1;
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{
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let f = |x, z| x + y + z;
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once(f)
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}
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}
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fn boxed(f: Box<dyn FnOnce() -> i32>) -> i32 {
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f()
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}
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fn main() {
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assert_eq!(simple(), 12);
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assert_eq!(crazy_closure(), (84, 10, 10));
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assert_eq!(closure_arg_adjustment_problem(), 3);
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assert_eq!(fn_once_closure_with_multiple_args(), 6);
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assert_eq!(boxed(Box::new({let x = 13; move || x})), 13);
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}
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