mirror of https://github.com/rust-lang/rust
45 lines
1002 B
Rust
45 lines
1002 B
Rust
//@ run-pass
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#![allow(dead_code)]
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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 codegen a version of the function
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pub fn do_stuff(mut f: Foo<Box<dyn Iterator<Item=u32>>, Box<dyn 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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