23 lines
849 B
Rust
23 lines
849 B
Rust
// Copyright 2012 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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#![allow(warnings)]
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// Here the type of `c` is `Option<?T>`, where `?T` is unconstrained.
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// Because there is data-flow from the `{ return; }` block, which
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// diverges and hence has type `!`, into `c`, we will default `?T` to
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// `!`, and hence this code compiles rather than failing and requiring
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// a type annotation.
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fn main() {
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let c = Some({ return; });
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c.unwrap();
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}
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