57 lines
2.0 KiB
Rust
57 lines
2.0 KiB
Rust
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// 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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// Test which of the builtin types are considered freezeable.
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fn assert_freeze<T:Freeze>() { }
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trait Dummy { }
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fn test<'a,T,U:Freeze>(_: &'a int) {
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// lifetime pointers are ok...
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assert_freeze::<&'static int>();
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assert_freeze::<&'a int>();
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assert_freeze::<&'a str>();
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assert_freeze::<&'a [int]>();
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// ...unless they are mutable
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assert_freeze::<&'static mut int>(); //~ ERROR does not fulfill `Freeze`
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assert_freeze::<&'a mut int>(); //~ ERROR does not fulfill `Freeze`
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// ~ pointers are ok
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assert_freeze::<~int>();
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assert_freeze::<~str>();
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assert_freeze::<~[int]>();
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// but not if they own a bad thing
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assert_freeze::<~&'a mut int>(); //~ ERROR does not fulfill `Freeze`
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// careful with object types, who knows what they close over...
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assert_freeze::<&'a Dummy>(); //~ ERROR does not fulfill `Freeze`
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assert_freeze::<~Dummy>(); //~ ERROR does not fulfill `Freeze`
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// ...unless they are properly bounded
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assert_freeze::<&'a Dummy:Freeze>();
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assert_freeze::<&'static Dummy:Freeze>();
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assert_freeze::<~Dummy:Freeze>();
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// ...but even then the pointer overrides
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assert_freeze::<&'a mut Dummy:Freeze>(); //~ ERROR does not fulfill `Freeze`
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// closures are like an `&mut` object
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assert_freeze::<&fn()>(); //~ ERROR does not fulfill `Freeze`
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// unsafe ptrs are ok unless they point at unfreezeable things
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assert_freeze::<*int>();
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assert_freeze::<*&'a mut int>(); //~ ERROR does not fulfill `Freeze`
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}
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fn main() {
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}
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