rust/src/test/rustdoc/synthetic_auto/basic.rs

// @has basic/struct.Foo.html
// @has - '//code' 'impl<T> Send for Foo<T> where T: Send'
// @has - '//code' 'impl<T> Sync for Foo<T> where T: Sync'
// @count - '//*[@id="implementations-list"]/*[@class="impl"]' 0
// @count - '//*[@id="synthetic-implementations-list"]/*[@class="impl"]' 2
pub struct Foo<T> {
    field: T,
}
Generate documentation for auto-trait impls A new section is added to both both struct and trait doc pages. On struct/enum pages, a new 'Auto Trait Implementations' section displays any synthetic implementations for auto traits. Currently, this is only done for Send and Sync. On trait pages, a new 'Auto Implementors' section displays all types which automatically implement the trait. Effectively, this is a list of all public types in the standard library. Synthesized impls for a particular auto trait ('synthetic impls') take into account generic bounds. For example, a type 'struct Foo<T>(T)' will have 'impl<T> Send for Foo<T> where T: Send' generated for it. Manual implementations of auto traits are also taken into account. If we have the following types: 'struct Foo<T>(T)' 'struct Wrapper<T>(Foo<T>)' 'unsafe impl<T> Send for Wrapper<T>' // pretend that Wrapper<T> makes this sound somehow Then Wrapper will have the following impl generated: 'impl<T> Send for Wrapper<T>' reflecting the fact that 'T: Send' need not hold for 'Wrapper<T>: Send' to hold Lifetimes, HRTBS, and projections (e.g. '<T as Iterator>::Item') are taken into account by synthetic impls However, if a type can never implement a particular auto trait (e.g. 'struct MyStruct<T>(*const T)'), then a negative impl will be generated (in this case, 'impl<T> !Send for MyStruct<T>') All of this means that a user should be able to copy-paste a synthetic impl into their code, without any observable changes in behavior (assuming the rest of the program remains unchanged). 2017-11-22 21:16:55 +00:00			`// @has basic/struct.Foo.html`
			`// @has - '//code' 'impl<T> Send for Foo<T> where T: Send'`
			`// @has - '//code' 'impl<T> Sync for Foo<T> where T: Sync'`
			`// @count - '//[@id="implementations-list"]/[@class="impl"]' 0`
			`// @count - '//[@id="synthetic-implementations-list"]/[@class="impl"]' 2`
			`pub struct Foo<T> {`
			`field: T,`
			`}`