40 lines
794 B
Rust
40 lines
794 B
Rust
//@ compile-flags:-Zverbose-internals
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#![allow(warnings)]
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#![feature(rustc_attrs)]
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use std::cell::Cell;
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// Invoke in such a way that the callee knows:
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//
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// - 'a: 'x
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//
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// and it must prove that `T: 'x`. Callee passes along `T: 'a`.
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fn twice<'a, F, T>(v: Cell<&'a ()>, value: T, mut f: F)
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where
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F: for<'x> FnMut(Option<Cell<&'a &'x ()>>, &T),
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{
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f(None, &value);
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f(None, &value);
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}
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#[rustc_regions]
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fn generic<T>(value: T) {
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let cell = Cell::new(&());
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twice(cell, value, |a, b| invoke(a, b));
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}
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#[rustc_regions]
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fn generic_fail<'a, T>(cell: Cell<&'a ()>, value: T) {
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twice(cell, value, |a, b| invoke(a, b));
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//~^ ERROR the parameter type `T` may not live long enough
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}
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fn invoke<'a, 'x, T>(x: Option<Cell<&'x &'a ()>>, y: &T)
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where
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T: 'x,
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{
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}
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fn main() {}
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