53 lines
1.4 KiB
Rust
53 lines
1.4 KiB
Rust
// Copyright 2015 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 code produces a CFG with critical edges that, if we don't
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// handle properly, will cause invalid codegen.
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#![feature(rustc_attrs)]
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enum State {
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Both,
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Front,
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Back
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}
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pub struct Foo<A: Iterator, B: Iterator> {
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state: State,
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a: A,
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b: B
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}
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impl<A, B> Foo<A, B>
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where A: Iterator, B: Iterator<Item=A::Item>
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{
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// This is the function we care about
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fn next(&mut self) -> Option<A::Item> {
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match self.state {
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State::Both => match self.a.next() {
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elt @ Some(..) => elt,
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None => {
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self.state = State::Back;
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self.b.next()
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}
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},
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State::Front => self.a.next(),
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State::Back => self.b.next(),
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}
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}
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}
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// Make sure we actually translate a version of the function
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pub fn do_stuff(mut f: Foo<Box<Iterator<Item=u32>>, Box<Iterator<Item=u32>>>) {
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let _x = f.next();
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}
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fn main() {}
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