43 lines
1.7 KiB
Rust
43 lines
1.7 KiB
Rust
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// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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// This is a regression test for the ICE from issue #10846.
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//
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// The original issue causing the ICE: the LUB-computations during
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// type inference were encountering late-bound lifetimes, and
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// asserting that such lifetimes should have already been substituted
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// with a concrete lifetime.
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//
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// However, those encounters were occurring within the lexical scope
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// of the binding for the late-bound lifetime; that is, the late-bound
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// lifetimes were perfectly valid. The core problem was that the type
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// folding code was over-zealously passing back all lifetimes when
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// doing region-folding, when really all clients of the region-folding
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// case only want to see FREE lifetime variables, not bound ones.
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#![feature(box_syntax)]
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pub fn main() {
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fn explicit() {
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fn test<F>(_x: Option<Box<F>>) where F: FnMut(Box<for<'a> FnMut(&'a isize)>) {}
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test(Some(box |_f: Box<for<'a> FnMut(&'a isize)>| {}));
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}
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// The code below is shorthand for the code above (and more likely
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// to represent what one encounters in practice).
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fn implicit() {
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fn test<F>(_x: Option<Box<F>>) where F: FnMut(Box< FnMut(& isize)>) {}
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test(Some(box |_f: Box< FnMut(& isize)>| {}));
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}
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explicit();
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implicit();
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}
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