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carllerche opened this issue Jan 14, 2015 · 1 comment · Fixed by #21252
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Unexpected error: the associated type <U as util::async::Async>::Value may not live long enough #21150

carllerche opened this issue Jan 14, 2015 · 1 comment · Fixed by #21252
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A-associated-items Area: Associated items (types, constants & functions)

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@carllerche
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I have been attempting to switch my Future / Stream lib to use associated types, however I have been hitting snags. Even though all the types (as far as I can tell) are bound by Send (and some by 'static too), I have been getting a lot of error messages:

/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:85:43: 90:26 error: the associated type `<U as util::async::Async>::Value` may not live long enough
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:85                         next.receive(move |res| {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:86                             match res {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:87                                 Ok(u) => c.complete(u),
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:88                                 Err(_) => unimplemented!(),
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:89                             }
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:90                         });
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:85:43: 90:26 help: consider adding an explicit lifetime bound `<U as util::async::Async>::Value: 'static`...
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:85                         next.receive(move |res| {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:86                             match res {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:87                                 Ok(u) => c.complete(u),
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:88                                 Err(_) => unimplemented!(),
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:89                             }
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:90                         });
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:85:43: 90:26 note: ...so that captured variable `c` does not outlive the enclosing closure
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:85                         next.receive(move |res| {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:86                             match res {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:87                                 Ok(u) => c.complete(u),
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:88                                 Err(_) => unimplemented!(),
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:89                             }
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:90                         });
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:85:30: 90:27 error: the associated type `<U as util::async::Async>::Value` may not live long enough
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:85                         next.receive(move |res| {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:86                             match res {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:87                                 Ok(u) => c.complete(u),
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:88                                 Err(_) => unimplemented!(),
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:89                             }
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:90                         });
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:85:30: 90:27 help: consider adding an explicit lifetime bound `<U as util::async::Async>::Value: 'static`...
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:85                         next.receive(move |res| {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:86                             match res {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:87                                 Ok(u) => c.complete(u),
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:88                                 Err(_) => unimplemented!(),
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:89                             }
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:90                         });
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:85:30: 90:27 note: ...so that the declared lifetime parameter bounds are satisfied
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:85                         next.receive(move |res| {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:86                             match res {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:87                                 Ok(u) => c.complete(u),
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:88                                 Err(_) => unimplemented!(),
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:89                             }
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:90                         });
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:82:31: 94:14 error: the associated type `<U as util::async::Async>::Value` may not live long enough
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:82             self.receive(move |res| {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:83                 match res {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:84                     Ok(_) => {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:85                         next.receive(move |res| {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:86                             match res {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:87                                 Ok(u) => c.complete(u),
                                                                ...
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:82:31: 94:14 help: consider adding an explicit lifetime bound `<U as util::async::Async>::Value: 'static`...
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:82             self.receive(move |res| {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:83                 match res {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:84                     Ok(_) => {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:85                         next.receive(move |res| {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:86                             match res {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:87                                 Ok(u) => c.complete(u),
                                                                ...
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:82:31: 94:14 note: ...so that captured variable `c` does not outlive the enclosing closure
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:82             self.receive(move |res| {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:83                 match res {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:84                     Ok(_) => {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:85                         next.receive(move |res| {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:86                             match res {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:87                                 Ok(u) => c.complete(u),
                                                                ...
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:82:18: 94:15 error: the associated type `<U as util::async::Async>::Value` may not live long enough
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:82             self.receive(move |res| {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:83                 match res {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:84                     Ok(_) => {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:85                         next.receive(move |res| {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:86                             match res {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:87                                 Ok(u) => c.complete(u),
                                                                ...
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:82:18: 94:15 help: consider adding an explicit lifetime bound `<U as util::async::Async>::Value: 'static`...
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:82             self.receive(move |res| {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:83                 match res {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:84                     Ok(_) => {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:85                         next.receive(move |res| {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:86                             match res {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:87                                 Ok(u) => c.complete(u),
                                                                ...
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:82:18: 94:15 note: ...so that the declared lifetime parameter bounds are satisfied
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:82             self.receive(move |res| {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:83                 match res {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:84                     Ok(_) => {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:85                         next.receive(move |res| {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:86                             match res {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:87                                 Ok(u) => c.complete(u),
                                                                ...
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:82:18: 94:15 error: the associated type `<U as util::async::Async>::Value` may not live long enough
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:82             self.receive(move |res| {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:83                 match res {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:84                     Ok(_) => {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:85                         next.receive(move |res| {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:86                             match res {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:87                                 Ok(u) => c.complete(u),
                                                                ...
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:82:18: 94:15 help: consider adding an explicit lifetime bound `<U as util::async::Async>::Value: 'static`...
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:82             self.receive(move |res| {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:83                 match res {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:84                     Ok(_) => {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:85                         next.receive(move |res| {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:86                             match res {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:87                                 Ok(u) => c.complete(u),
                                                                ...
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:82:18: 94:15 note: ...so that the declared lifetime parameter bounds are satisfied
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:82             self.receive(move |res| {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:83                 match res {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:84                     Ok(_) => {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:85                         next.receive(move |res| {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:86                             match res {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:87                                 Ok(u) => c.complete(u),
                                                                ...
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:82:18: 94:15 error: the associated type `<U as util::async::Async>::Value` may not live long enough
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:82             self.receive(move |res| {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:83                 match res {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:84                     Ok(_) => {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:85                         next.receive(move |res| {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:86                             match res {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:87                                 Ok(u) => c.complete(u),
                                                                ...
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:82:18: 94:15 help: consider adding an explicit lifetime bound `<U as util::async::Async>::Value: 'static`...
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:82             self.receive(move |res| {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:83                 match res {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:84                     Ok(_) => {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:85                         next.receive(move |res| {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:86                             match res {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:87                                 Ok(u) => c.complete(u),
                                                                ...
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:82:18: 94:15 note: ...so that the declared lifetime parameter bounds are satisfied
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:82             self.receive(move |res| {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:83                 match res {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:84                     Ok(_) => {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:85                         next.receive(move |res| {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:86                             match res {
/Users/carllerche/Code/mine/syncbox/src/util/async/future.rs:87                                 Ok(u) => c.complete(u),

The repro is trying to compile syncbox on the async-associated-type branch. Sorry for not reducing more 😢

https://github.com/carllerche/syncbox/tree/async-associated-type

cc @nikomatsakis
@nikomatsakis nikomatsakis added the A-associated-items Area: Associated items (types, constants & functions) label Jan 14, 2015
@chris-morgan
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Duplicate of #20890.

@nikomatsakis nikomatsakis mentioned this issue Jan 16, 2015
Merged
alexcrichton added a commit to alexcrichton/rust that referenced this issue Jan 21, 2015
@alexcrichton
rollup merge of rust-lang#21252: nikomatsakis/assoc-type-ice-hunt-take-2
036d8c4 
Project region bounds out of the trait when deciding whether a projection type outlives a given regions.

Fixes rust-lang#20890.
Fixes rust-lang#21150.
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Fixes for region bounds in traits nikomatsakis/rust
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@carllerche @nikomatsakis @chris-morgan