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#![feature(unboxed_closures, tuple_trait)]
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fn to_fn_once<A:std::marker::Tuple,F:FnOnce<A>>(f: F) -> F { f }
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fn main() {
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let r = {
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let x: Box<_> = Box::new(42);
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let f = to_fn_once(move|| &x); //~ ERROR cannot return reference to local data `x`
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f()
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};
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drop(r);
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}
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