Suggest adding a lifetime constraint for opaque type #67595

ohadravid · 2019-12-24T19:49:13Z

Fixes #67577, where code like this:

struct List {
  data: Vec<String>,
}
impl List {
  fn started_with<'a>(&'a self, prefix: &'a str) -> impl Iterator<Item=&'a str> {
    self.data.iter().filter(|s| s.starts_with(prefix)).map(|s| s.as_ref())
  }
}

will show this error:

   Compiling playground v0.0.1 (/playground)
error[E0597]: `prefix` does not live long enough
 --> src/lib.rs:6:47
  |
5 |   fn started_with<'a>(&'a self, prefix: &'a str) -> impl Iterator<Item=&'a str> {
  |                   -- lifetime `'a` defined here     --------------------------- opaque type requires that `prefix` is borrowed for `'a`
...

but without suggesting the lovely help: you can add a constraint...

r? @estebank

src/librustc_mir/borrow_check/diagnostics/explain_borrow.rs

estebank

r=me after dealing with the nitpicks

src/librustc_mir/borrow_check/diagnostics/explain_borrow.rs

estebank · 2019-12-25T18:38:10Z

@bors r+

bors · 2019-12-25T18:38:12Z

📌 Commit 3e9d1cc has been approved by estebank

@estebank

…long-enough, r=estebank Suggest adding a lifetime constraint for opaque type Fixes rust-lang#67577, where code like this: ``` struct List { data: Vec<String>, } impl List { fn started_with<'a>(&'a self, prefix: &'a str) -> impl Iterator<Item=&'a str> { self.data.iter().filter(|s| s.starts_with(prefix)).map(|s| s.as_ref()) } } ``` will show this error: ``` Compiling playground v0.0.1 (/playground) error[E0597]: `prefix` does not live long enough --> src/lib.rs:6:47 | 5 | fn started_with<'a>(&'a self, prefix: &'a str) -> impl Iterator<Item=&'a str> { | -- lifetime `'a` defined here --------------------------- opaque type requires that `prefix` is borrowed for `'a` ... ``` but without suggesting the lovely `help: you can add a constraint..`. r? @estebank

Mark-Simulacrum · 2019-12-26T22:26:23Z

Looks like this might need to be rebased atop master (see https://rust-lang.github.io/rust-log-analyzer/log-viewer/#https://dev.azure.com/rust-lang/e71b0ddf-dd27-435a-873c-e30f86eea377/_apis/build/builds/16871/logs/1534 from #67643 (comment)).

@bors r-

Mingun · 2019-12-28T11:23:36Z

src/librustc_mir/borrow_check/diagnostics/explain_borrow.rs

+                            region_name,
+                        ),
+                        format!("{} + {}", snippet, suggestable_name),
+                        Applicability::Unspecified,


It seems that this fix can be applied automatically, isn't it?

I used the same Applicability as the other suggestions for impl Trait lifetimes.
I don't think we can be sure this snippet will work (@estebank just fixed an issue with ; for example)

…for "does not live long enough" error

ohadravid · 2019-12-30T20:31:11Z

@Mark-Simulacrum rebased and the CI is green 😄

Mark-Simulacrum · 2019-12-30T21:51:13Z

@bors r=estebank

Thanks!

bors · 2019-12-30T21:51:14Z

📌 Commit cd73034 has been approved by estebank

bors · 2019-12-31T06:44:51Z

⌛ Testing commit cd73034 with merge 8e49171...

@estebank

…, r=estebank Suggest adding a lifetime constraint for opaque type Fixes #67577, where code like this: ``` struct List { data: Vec<String>, } impl List { fn started_with<'a>(&'a self, prefix: &'a str) -> impl Iterator<Item=&'a str> { self.data.iter().filter(|s| s.starts_with(prefix)).map(|s| s.as_ref()) } } ``` will show this error: ``` Compiling playground v0.0.1 (/playground) error[E0597]: `prefix` does not live long enough --> src/lib.rs:6:47 | 5 | fn started_with<'a>(&'a self, prefix: &'a str) -> impl Iterator<Item=&'a str> { | -- lifetime `'a` defined here --------------------------- opaque type requires that `prefix` is borrowed for `'a` ... ``` but without suggesting the lovely `help: you can add a constraint..`. r? @estebank

rust-highfive · 2019-12-31T09:50:25Z

The job x86_64-gnu-nopt of your PR failed (pretty log, raw log). Through arcane magic we have determined that the following fragments from the build log may contain information about the problem.

Click to expand the log.

2019-12-31T08:36:01.2387712Z 
2019-12-31T08:36:01.2387979Z 6    |              |
2019-12-31T08:36:01.2388707Z 7    |              let's call the lifetime of this reference `'1`
2019-12-31T08:36:01.2389061Z 8    |
2019-12-31T08:36:01.2395759Z - help: to allow this `impl Trait` to capture borrowed data with lifetime `'1`, add `'_` as a constraint
2019-12-31T08:36:01.2396353Z + help: to allow this `impl Trait` to capture borrowed data with lifetime `'1`, add `'_` as a bound
2019-12-31T08:36:01.2396470Z 10    |
2019-12-31T08:36:01.2396733Z 11 LL | fn elided(x: &i32) -> impl Copy + '_ { x }
2019-12-31T08:36:01.2396876Z 
2019-12-31T08:36:01.2397137Z 20    |             lifetime `'a` defined here
2019-12-31T08:36:01.2397210Z 21    |
2019-12-31T08:36:01.2397475Z 22    = help: consider replacing `'a` with `'static`
2019-12-31T08:36:01.2397475Z 22    = help: consider replacing `'a` with `'static`
2019-12-31T08:36:01.2397797Z - help: to allow this `impl Trait` to capture borrowed data with lifetime `'a`, add `'a` as a constraint
2019-12-31T08:36:01.2401779Z + help: to allow this `impl Trait` to capture borrowed data with lifetime `'a`, add `'a` as a bound
2019-12-31T08:36:01.2401892Z 24    |
2019-12-31T08:36:01.2402199Z 25 LL | fn explicit<'a>(x: &'a i32) -> impl Copy + 'a { x }
2019-12-31T08:36:01.2402354Z 
2019-12-31T08:36:01.2402389Z 
2019-12-31T08:36:01.2402473Z The actual stderr differed from the expected stderr.
2019-12-31T08:36:01.2402473Z The actual stderr differed from the expected stderr.
2019-12-31T08:36:01.2402886Z Actual stderr saved to /checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/impl-trait/must_outlive_least_region_or_bound.nll/must_outlive_least_region_or_bound.nll.stderr
2019-12-31T08:36:01.2403223Z To update references, rerun the tests and pass the `--bless` flag
2019-12-31T08:36:01.2406275Z To only update this specific test, also pass `--test-args impl-trait/must_outlive_least_region_or_bound.rs`
2019-12-31T08:36:01.2406437Z error: 1 errors occurred comparing output.
2019-12-31T08:36:01.2406541Z status: exit code: 1
2019-12-31T08:36:01.2406541Z status: exit code: 1
2019-12-31T08:36:01.2407805Z command: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/src/test/ui/impl-trait/must_outlive_least_region_or_bound.rs" "-Zthreads=1" "--target=x86_64-unknown-linux-gnu" "--error-format" "json" "-Zui-testing" "--emit" "metadata" "-C" "prefer-dynamic" "--out-dir" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/impl-trait/must_outlive_least_region_or_bound.nll" "-Zborrowck=mir" "-Crpath" "-Cdebuginfo=0" "-Zunstable-options" "-Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "-L" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/impl-trait/must_outlive_least_region_or_bound.nll/auxiliary" "-A" "unused"
2019-12-31T08:36:01.2408418Z ------------------------------------------
2019-12-31T08:36:01.2408488Z 
2019-12-31T08:36:01.2408755Z ------------------------------------------
2019-12-31T08:36:01.2409132Z stderr:
2019-12-31T08:36:01.2409132Z stderr:
2019-12-31T08:36:01.2409467Z ------------------------------------------
2019-12-31T08:36:01.2409563Z error: lifetime may not live long enough
2019-12-31T08:36:01.2409886Z   --> /checkout/src/test/ui/impl-trait/must_outlive_least_region_or_bound.rs:3:23
2019-12-31T08:36:01.2409993Z    |
2019-12-31T08:36:01.2410258Z LL | fn elided(x: &i32) -> impl Copy { x }
2019-12-31T08:36:01.2410596Z    |              -        ^^^^^^^^^ opaque type requires that `'1` must outlive `'static`
2019-12-31T08:36:01.2418370Z    |              let's call the lifetime of this reference `'1`
2019-12-31T08:36:01.2418477Z    |
2019-12-31T08:36:01.2418477Z    |
2019-12-31T08:36:01.2418796Z help: to allow this `impl Trait` to capture borrowed data with lifetime `'1`, add `'_` as a bound
2019-12-31T08:36:01.2418902Z    |
2019-12-31T08:36:01.2419155Z LL | fn elided(x: &i32) -> impl Copy + '_ { x }
2019-12-31T08:36:01.2419313Z 
2019-12-31T08:36:01.2419551Z error: lifetime may not live long enough
2019-12-31T08:36:01.2419903Z   --> /checkout/src/test/ui/impl-trait/must_outlive_least_region_or_bound.rs:6:32
2019-12-31T08:36:01.2420004Z    |
2019-12-31T08:36:01.2420004Z    |
2019-12-31T08:36:01.2420254Z LL | fn explicit<'a>(x: &'a i32) -> impl Copy { x }
2019-12-31T08:36:01.2420582Z    |             --                 ^^^^^^^^^ opaque type requires that `'a` must outlive `'static`
2019-12-31T08:36:01.2420931Z    |             lifetime `'a` defined here
2019-12-31T08:36:01.2421002Z    |
2019-12-31T08:36:01.2421261Z    = help: consider replacing `'a` with `'static`
2019-12-31T08:36:01.2421261Z    = help: consider replacing `'a` with `'static`
2019-12-31T08:36:01.2421586Z help: to allow this `impl Trait` to capture borrowed data with lifetime `'a`, add `'a` as a bound
2019-12-31T08:36:01.2421672Z    |
2019-12-31T08:36:01.2421942Z LL | fn explicit<'a>(x: &'a i32) -> impl Copy + 'a { x }
2019-12-31T08:36:01.2422567Z 
2019-12-31T08:36:01.2422682Z error: lifetime may not live long enough
2019-12-31T08:36:01.2423312Z   --> /checkout/src/test/ui/impl-trait/must_outlive_least_region_or_bound.rs:12:69
2019-12-31T08:36:01.2423415Z    |
2019-12-31T08:36:01.2423415Z    |
2019-12-31T08:36:01.2424112Z LL | fn with_bound<'a>(x: &'a i32) -> impl LifetimeTrait<'a> + 'static { x }
2019-12-31T08:36:01.2424548Z    |               -- lifetime `'a` defined here                         ^ returning this value requires that `'a` must outlive `'static`
2019-12-31T08:36:01.2425026Z    = help: consider replacing `'a` with `'static`
2019-12-31T08:36:01.2425368Z    = help: consider replacing `'a` with `'static`
2019-12-31T08:36:01.2425428Z 
2019-12-31T08:36:01.2425519Z error: lifetime may not live long enough
2019-12-31T08:36:01.2425519Z error: lifetime may not live long enough
2019-12-31T08:36:01.2425879Z   --> /checkout/src/test/ui/impl-trait/must_outlive_least_region_or_bound.rs:17:61
2019-12-31T08:36:01.2425996Z    |
2019-12-31T08:36:01.2426340Z LL | fn move_lifetime_into_fn<'a, 'b>(x: &'a u32, y: &'b u32) -> impl Fn(&'a u32) {
2019-12-31T08:36:01.2426823Z    |                          --  -- lifetime `'b` defined here  ^^^^^^^^^^^^^^^^ opaque type requires that `'b` must outlive `'a`
2019-12-31T08:36:01.2427283Z    |                          lifetime `'a` defined here
2019-12-31T08:36:01.2427388Z    |
2019-12-31T08:36:01.2427691Z    = help: consider adding the following bound: `'b: 'a`
2019-12-31T08:36:01.2427770Z 
2019-12-31T08:36:01.2427770Z 
2019-12-31T08:36:01.2427852Z error[E0310]: the parameter type `T` may not live long enough
2019-12-31T08:36:01.2428228Z   --> /checkout/src/test/ui/impl-trait/must_outlive_least_region_or_bound.rs:22:51
2019-12-31T08:36:01.2428327Z    |
2019-12-31T08:36:01.2428674Z LL | fn ty_param_wont_outlive_static<T:Debug>(x: T) -> impl Debug + 'static {
2019-12-31T08:36:01.2428899Z    |
2019-12-31T08:36:01.2429233Z    = help: consider adding an explicit lifetime bound `T: 'static`...
2019-12-31T08:36:01.2429326Z 
2019-12-31T08:36:01.2429400Z error: aborting due to 5 previous errors
---
2019-12-31T08:36:01.2430756Z 
2019-12-31T08:36:01.2430822Z 6    |                         |
2019-12-31T08:36:01.2431184Z 7    |                         let's call the lifetime of this reference `'1`
2019-12-31T08:36:01.2431296Z 8    |
2019-12-31T08:36:01.2431665Z - help: to allow this `impl Trait` to capture borrowed data with lifetime `'1`, add `'_` as a constraint
2019-12-31T08:36:01.2432074Z + help: to allow this `impl Trait` to capture borrowed data with lifetime `'1`, add `'_` as a bound
2019-12-31T08:36:01.2432329Z 10    |
2019-12-31T08:36:01.2432724Z 11 LL |     fn iter_values_anon(&self) -> impl Iterator<Item=u32> + '_ {
2019-12-31T08:36:01.2432913Z 
2019-12-31T08:36:01.2433221Z 20    |                    lifetime `'a` defined here
2019-12-31T08:36:01.2433324Z 21    |
2019-12-31T08:36:01.2433623Z 22    = help: consider replacing `'a` with `'static`
2019-12-31T08:36:01.2433623Z 22    = help: consider replacing `'a` with `'static`
2019-12-31T08:36:01.2434022Z - help: to allow this `impl Trait` to capture borrowed data with lifetime `'a`, add `'a` as a constraint
2019-12-31T08:36:01.2434409Z + help: to allow this `impl Trait` to capture borrowed data with lifetime `'a`, add `'a` as a bound
2019-12-31T08:36:01.2434530Z 24    |
2019-12-31T08:36:01.2434873Z 25 LL |     fn iter_values<'a>(&'a self) -> impl Iterator<Item=u32> + 'a {
2019-12-31T08:36:01.2435166Z 
2019-12-31T08:36:01.2435237Z 
2019-12-31T08:36:01.2435316Z The actual stderr differed from the expected stderr.
2019-12-31T08:36:01.2435316Z The actual stderr differed from the expected stderr.
2019-12-31T08:36:01.2435828Z Actual stderr saved to /checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/impl-trait/static-return-lifetime-infered.nll/static-return-lifetime-infered.nll.stderr
2019-12-31T08:36:01.2436197Z To update references, rerun the tests and pass the `--bless` flag
2019-12-31T08:36:01.2436596Z To only update this specific test, also pass `--test-args impl-trait/static-return-lifetime-infered.rs`
2019-12-31T08:36:01.2436763Z error: 1 errors occurred comparing output.
2019-12-31T08:36:01.2436845Z status: exit code: 1
2019-12-31T08:36:01.2436845Z status: exit code: 1
2019-12-31T08:36:01.2438129Z command: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/src/test/ui/impl-trait/static-return-lifetime-infered.rs" "-Zthreads=1" "--target=x86_64-unknown-linux-gnu" "--error-format" "json" "-Zui-testing" "--emit" "metadata" "-C" "prefer-dynamic" "--out-dir" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/impl-trait/static-return-lifetime-infered.nll" "-Zborrowck=mir" "-Crpath" "-Cdebuginfo=0" "-Zunstable-options" "-Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "-L" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/impl-trait/static-return-lifetime-infered.nll/auxiliary" "-A" "unused"
2019-12-31T08:36:01.2438798Z ------------------------------------------
2019-12-31T08:36:01.2438857Z 
2019-12-31T08:36:01.2439165Z ------------------------------------------
2019-12-31T08:36:01.2439249Z stderr:
2019-12-31T08:36:01.2439249Z stderr:
2019-12-31T08:36:01.2439545Z ------------------------------------------
2019-12-31T08:36:01.2439632Z error: lifetime may not live long enough
2019-12-31T08:36:01.2439993Z   --> /checkout/src/test/ui/impl-trait/static-return-lifetime-infered.rs:6:35
2019-12-31T08:36:01.2440090Z    |
2019-12-31T08:36:01.2440439Z LL |     fn iter_values_anon(&self) -> impl Iterator<Item=u32> {
2019-12-31T08:36:01.2440848Z    |                         -         ^^^^^^^^^^^^^^^^^^^^^^^ opaque type requires that `'1` must outlive `'static`
2019-12-31T08:36:01.2441341Z    |                         let's call the lifetime of this reference `'1`
2019-12-31T08:36:01.2441438Z    |
2019-12-31T08:36:01.2441438Z    |
2019-12-31T08:36:01.2441811Z help: to allow this `impl Trait` to capture borrowed data with lifetime `'1`, add `'_` as a bound
2019-12-31T08:36:01.2441913Z    |
2019-12-31T08:36:01.2442254Z LL |     fn iter_values_anon(&self) -> impl Iterator<Item=u32> + '_ {
2019-12-31T08:36:01.2442440Z 
2019-12-31T08:36:01.2442512Z error: lifetime may not live long enough
2019-12-31T08:36:01.2442870Z   --> /checkout/src/test/ui/impl-trait/static-return-lifetime-infered.rs:10:37
2019-12-31T08:36:01.2442976Z    |
2019-12-31T08:36:01.2442976Z    |
2019-12-31T08:36:01.2443411Z LL |     fn iter_values<'a>(&'a self) -> impl Iterator<Item=u32> {
2019-12-31T08:36:01.2443850Z    |                    --               ^^^^^^^^^^^^^^^^^^^^^^^ opaque type requires that `'a` must outlive `'static`
2019-12-31T08:36:01.2444301Z    |                    lifetime `'a` defined here
2019-12-31T08:36:01.2444386Z    |
2019-12-31T08:36:01.2444699Z    = help: consider replacing `'a` with `'static`
2019-12-31T08:36:01.2444699Z    = help: consider replacing `'a` with `'static`
2019-12-31T08:36:01.2445072Z help: to allow this `impl Trait` to capture borrowed data with lifetime `'a`, add `'a` as a bound
2019-12-31T08:36:01.2445191Z    |
2019-12-31T08:36:01.2445514Z LL |     fn iter_values<'a>(&'a self) -> impl Iterator<Item=u32> + 'a {
2019-12-31T08:36:01.2445700Z 
2019-12-31T08:36:01.2445787Z error: aborting due to 2 previous errors
2019-12-31T08:36:01.2445839Z 
2019-12-31T08:36:01.2445879Z 
---
2019-12-31T08:36:01.2446940Z 
2019-12-31T08:36:01.2447010Z 6    |                          |
2019-12-31T08:36:01.2447370Z 7    |                          let's call the lifetime of this reference `'1`
2019-12-31T08:36:01.2447465Z 8    |
2019-12-31T08:36:01.2447855Z - help: to allow this `impl Trait` to capture borrowed data with lifetime `'1`, add `'_` as a constraint
2019-12-31T08:36:01.2448264Z + help: to allow this `impl Trait` to capture borrowed data with lifetime `'1`, add `'_` as a bound
2019-12-31T08:36:01.2448368Z 10    |
2019-12-31T08:36:01.2448706Z 11 LL |     async fn f(self: Pin<&Self>) -> impl Clone + '_ { self }
2019-12-31T08:36:01.2448897Z 
2019-12-31T08:36:01.2448938Z 
2019-12-31T08:36:01.2449026Z The actual stderr differed from the expected stderr.
2019-12-31T08:36:01.2449026Z The actual stderr differed from the expected stderr.
2019-12-31T08:36:01.2449566Z Actual stderr saved to /checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/self/arbitrary_self_types_pin_lifetime_impl_trait-async.nll/arbitrary_self_types_pin_lifetime_impl_trait-async.nll.stderr
2019-12-31T08:36:01.2449968Z To update references, rerun the tests and pass the `--bless` flag
2019-12-31T08:36:01.2450381Z To only update this specific test, also pass `--test-args self/arbitrary_self_types_pin_lifetime_impl_trait-async.rs`
2019-12-31T08:36:01.2450559Z error: 1 errors occurred comparing output.
2019-12-31T08:36:01.2450657Z status: exit code: 1
2019-12-31T08:36:01.2450657Z status: exit code: 1
2019-12-31T08:36:01.2452011Z command: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/src/test/ui/self/arbitrary_self_types_pin_lifetime_impl_trait-async.rs" "-Zthreads=1" "--target=x86_64-unknown-linux-gnu" "--error-format" "json" "-Zui-testing" "--emit" "metadata" "-C" "prefer-dynamic" "--out-dir" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/self/arbitrary_self_types_pin_lifetime_impl_trait-async.nll" "-Zborrowck=mir" "-Crpath" "-Cdebuginfo=0" "-Zunstable-options" "-Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "--edition=2018" "-L" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/self/arbitrary_self_types_pin_lifetime_impl_trait-async.nll/auxiliary" "-A" "unused"
2019-12-31T08:36:01.2452708Z ------------------------------------------
2019-12-31T08:36:01.2452767Z 
2019-12-31T08:36:01.2453071Z ------------------------------------------
2019-12-31T08:36:01.2453154Z stderr:
2019-12-31T08:36:01.2453154Z stderr:
2019-12-31T08:36:01.2453450Z ------------------------------------------
2019-12-31T08:36:01.2453553Z error: lifetime may not live long enough
2019-12-31T08:36:01.2453922Z   --> /checkout/src/test/ui/self/arbitrary_self_types_pin_lifetime_impl_trait-async.rs:8:48
2019-12-31T08:36:01.2454054Z    |
2019-12-31T08:36:01.2454466Z LL |     async fn f(self: Pin<&Self>) -> impl Clone { self }
2019-12-31T08:36:01.2454940Z    |                          -                     ^^^^^^^^ returning this value requires that `'1` must outlive `'static`
2019-12-31T08:36:01.2455427Z    |                          let's call the lifetime of this reference `'1`
2019-12-31T08:36:01.2455538Z    |
2019-12-31T08:36:01.2455538Z    |
2019-12-31T08:36:01.2455895Z help: to allow this `impl Trait` to capture borrowed data with lifetime `'1`, add `'_` as a bound
2019-12-31T08:36:01.2456013Z    |
2019-12-31T08:36:01.2456322Z LL |     async fn f(self: Pin<&Self>) -> impl Clone + '_ { self }
2019-12-31T08:36:01.2456500Z 
2019-12-31T08:36:01.2456585Z error: aborting due to previous error
2019-12-31T08:36:01.2456637Z 
2019-12-31T08:36:01.2456676Z 
---
2019-12-31T08:36:01.2457725Z 
2019-12-31T08:36:01.2457793Z 6    |                    |
2019-12-31T08:36:01.2458145Z 7    |                    let's call the lifetime of this reference `'1`
2019-12-31T08:36:01.2458238Z 8    |
2019-12-31T08:36:01.2458619Z - help: to allow this `impl Trait` to capture borrowed data with lifetime `'1`, add `'_` as a constraint
2019-12-31T08:36:01.2459007Z + help: to allow this `impl Trait` to capture borrowed data with lifetime `'1`, add `'_` as a bound
2019-12-31T08:36:01.2459125Z 10    |
2019-12-31T08:36:01.2459453Z 11 LL |     fn f(self: Pin<&Self>) -> impl Clone + '_ { self }
2019-12-31T08:36:01.2459612Z 
2019-12-31T08:36:01.2459680Z 
2019-12-31T08:36:01.2459758Z The actual stderr differed from the expected stderr.
2019-12-31T08:36:01.2459758Z The actual stderr differed from the expected stderr.
2019-12-31T08:36:01.2460293Z Actual stderr saved to /checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/self/arbitrary_self_types_pin_lifetime_impl_trait.nll/arbitrary_self_types_pin_lifetime_impl_trait.nll.stderr
2019-12-31T08:36:01.2460695Z To update references, rerun the tests and pass the `--bless` flag
2019-12-31T08:36:01.2461097Z To only update this specific test, also pass `--test-args self/arbitrary_self_types_pin_lifetime_impl_trait.rs`
2019-12-31T08:36:01.2461274Z error: 1 errors occurred comparing output.
2019-12-31T08:36:01.2461373Z status: exit code: 1
2019-12-31T08:36:01.2461373Z status: exit code: 1
2019-12-31T08:36:01.2462671Z command: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/src/test/ui/self/arbitrary_self_types_pin_lifetime_impl_trait.rs" "-Zthreads=1" "--target=x86_64-unknown-linux-gnu" "--error-format" "json" "-Zui-testing" "--emit" "metadata" "-C" "prefer-dynamic" "--out-dir" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/self/arbitrary_self_types_pin_lifetime_impl_trait.nll" "-Zborrowck=mir" "-Crpath" "-Cdebuginfo=0" "-Zunstable-options" "-Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "-L" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/self/arbitrary_self_types_pin_lifetime_impl_trait.nll/auxiliary" "-A" "unused"
2019-12-31T08:36:01.2463355Z ------------------------------------------
2019-12-31T08:36:01.2463413Z 
2019-12-31T08:36:01.2463714Z ------------------------------------------
2019-12-31T08:36:01.2463796Z stderr:
2019-12-31T08:36:01.2463796Z stderr:
2019-12-31T08:36:01.2464093Z ------------------------------------------
2019-12-31T08:36:01.2464178Z error: lifetime may not live long enough
2019-12-31T08:36:01.2464549Z   --> /checkout/src/test/ui/self/arbitrary_self_types_pin_lifetime_impl_trait.rs:8:31
2019-12-31T08:36:01.2464666Z    |
2019-12-31T08:36:01.2465031Z LL |     fn f(self: Pin<&Self>) -> impl Clone { self } //~ ERROR cannot infer an appropriate lifetime
2019-12-31T08:36:01.2465543Z    |                    -          ^^^^^^^^^^ opaque type requires that `'1` must outlive `'static`
2019-12-31T08:36:01.2466030Z    |                    let's call the lifetime of this reference `'1`
2019-12-31T08:36:01.2466122Z    |
2019-12-31T08:36:01.2466122Z    |
2019-12-31T08:36:01.2466497Z help: to allow this `impl Trait` to capture borrowed data with lifetime `'1`, add `'_` as a bound
2019-12-31T08:36:01.2466613Z    |
2019-12-31T08:36:01.2466982Z LL |     fn f(self: Pin<&Self>) -> impl Clone + '_ { self } //~ ERROR cannot infer an appropriate lifetime
2019-12-31T08:36:01.2467171Z 
2019-12-31T08:36:01.2467240Z error: aborting due to previous error
2019-12-31T08:36:01.2467311Z 
2019-12-31T08:36:01.2467351Z 
---
2019-12-31T08:36:01.2470098Z thread 'main' panicked at 'Some tests failed', src/tools/compiletest/src/main.rs:385:22
2019-12-31T08:36:01.2470232Z note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace.
2019-12-31T08:36:01.2470300Z 
2019-12-31T08:36:01.2470341Z 
2019-12-31T08:36:01.2472963Z command did not execute successfully: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage0-tools-bin/compiletest" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage0-tools-bin/compiletest" "--compile-lib-path" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib" "--run-lib-path" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib/rustlib/x86_64-unknown-linux-gnu/lib" "--rustc-path" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "--src-base" "/checkout/src/test/ui" "--build-base" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui" "--stage-id" "stage2-x86_64-unknown-linux-gnu" "--mode" "ui" "--target" "x86_64-unknown-linux-gnu" "--host" "x86_64-unknown-linux-gnu" "--llvm-filecheck" "/checkout/obj/build/x86_64-unknown-linux-gnu/llvm/build/bin/FileCheck" "--host-rustcflags" "-Crpath -Cdebuginfo=0 -Zunstable-options  -Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "--target-rustcflags" "-Crpath -Cdebuginfo=0 -Zunstable-options  -Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "--docck-python" "/usr/bin/python2.7" "--lldb-python" "/usr/bin/python2.7" "--gdb" "/usr/bin/gdb" "--llvm-version" "9.0.0-rust-1.42.0-nightly\n" "--cc" "" "--cxx" "" "--cflags" "" "--llvm-components" "" "--llvm-cxxflags" "" "--adb-path" "adb" "--adb-test-dir" "/data/tmp/work" "--android-cross-path" "" "--color" "always" "--compare-mode" "nll"
2019-12-31T08:36:01.2475264Z 
2019-12-31T08:36:01.2475333Z 
2019-12-31T08:36:01.2491369Z failed to run: /checkout/obj/build/bootstrap/debug/bootstrap test
2019-12-31T08:36:01.2491500Z Build completed unsuccessfully in 1:45:47
2019-12-31T08:36:01.2491500Z Build completed unsuccessfully in 1:45:47
2019-12-31T08:36:01.2543780Z == clock drift check ==
2019-12-31T08:36:01.2556451Z   local time: Tue Dec 31 08:36:01 UTC 2019
2019-12-31T08:36:01.5241612Z   network time: Tue, 31 Dec 2019 08:36:01 GMT
2019-12-31T08:36:01.5245665Z == end clock drift check ==
2019-12-31T08:36:02.6271752Z 
2019-12-31T08:36:02.6392981Z ##[error]Bash exited with code '1'.
2019-12-31T08:36:02.6439814Z ##[section]Starting: Checkout
2019-12-31T08:36:02.6442035Z ==============================================================================
2019-12-31T08:36:02.6458188Z Task         : Get sources
2019-12-31T08:36:02.6458300Z Description  : Get sources from a repository. Supports Git, TfsVC, and SVN repositories.

I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact @TimNN. (Feature Requests)

bors · 2019-12-31T09:50:42Z

💔 Test failed - checks-azure

…int` to `bound`

ohadravid · 2019-12-31T13:24:17Z

Ah it was --compare-mode=nll.. sorry about that! I blessed it again and now it should also pass the full CI 😄 @Mark-Simulacrum

Dylan-DPC-zz · 2020-01-02T09:49:48Z

@bors r=estebank

bors · 2020-01-02T09:49:49Z

📌 Commit 1a4f6b8 has been approved by estebank

@estebank

…long-enough, r=estebank Suggest adding a lifetime constraint for opaque type Fixes rust-lang#67577, where code like this: ``` struct List { data: Vec<String>, } impl List { fn started_with<'a>(&'a self, prefix: &'a str) -> impl Iterator<Item=&'a str> { self.data.iter().filter(|s| s.starts_with(prefix)).map(|s| s.as_ref()) } } ``` will show this error: ``` Compiling playground v0.0.1 (/playground) error[E0597]: `prefix` does not live long enough --> src/lib.rs:6:47 | 5 | fn started_with<'a>(&'a self, prefix: &'a str) -> impl Iterator<Item=&'a str> { | -- lifetime `'a` defined here --------------------------- opaque type requires that `prefix` is borrowed for `'a` ... ``` but without suggesting the lovely `help: you can add a constraint..`. r? @estebank

@ghost

Rollup of 10 pull requests Successful merges: - #67450 (Allow for setting a ThinLTO import limit during bootstrap) - #67595 (Suggest adding a lifetime constraint for opaque type) - #67636 (allow rustfmt key in [build] section) - #67736 (Less-than is asymmetric, not antisymmetric) - #67762 (Add missing links for insecure_time) - #67783 (Warn for bindings named same as variants when matching against a borrow) - #67796 (Ensure that we process projections during MIR inlining) - #67807 (Use drop instead of the toilet closure `|_| ()`) - #67816 (Clean up err codes) - #67825 (Minor: change take() docs grammar to match other docs) Failed merges: r? @ghost

rust-highfive assigned estebank Dec 24, 2019

rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Dec 24, 2019

Centril reviewed Dec 24, 2019

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src/librustc_mir/borrow_check/diagnostics/explain_borrow.rs Outdated Show resolved Hide resolved

src/librustc_mir/borrow_check/diagnostics/explain_borrow.rs Outdated Show resolved Hide resolved

estebank approved these changes Dec 24, 2019

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ohadravid force-pushed the impl-trait-does-not-live-long-enough branch from ce292d3 to 3f53c1a Compare December 24, 2019 21:53

estebank reviewed Dec 24, 2019

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src/librustc_mir/borrow_check/diagnostics/explain_borrow.rs Outdated Show resolved Hide resolved

ohadravid force-pushed the impl-trait-does-not-live-long-enough branch from 3f53c1a to 94089ad Compare December 25, 2019 07:54

bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Dec 25, 2019

Mark-Simulacrum mentioned this pull request Dec 26, 2019

Rollup of 13 pull requests #67643

Closed

bors added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. labels Dec 26, 2019

ohadravid force-pushed the impl-trait-does-not-live-long-enough branch from 3e9d1cc to e9a9e07 Compare December 27, 2019 12:18

Mingun reviewed Dec 28, 2019

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Suggest adding a lifetime constraint when opaque type is responsible …

d4fbb55

…for "does not live long enough" error

ohadravid force-pushed the impl-trait-does-not-live-long-enough branch from e9a9e07 to cd73034 Compare December 30, 2019 18:23

bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Dec 30, 2019

bors added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. labels Dec 31, 2019

Change wording for lifetime suggestion for opaque types from `constra…

1a4f6b8

…int` to `bound`

ohadravid force-pushed the impl-trait-does-not-live-long-enough branch from cd73034 to 1a4f6b8 Compare December 31, 2019 11:13

bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Jan 2, 2020

JohnTitor mentioned this pull request Jan 3, 2020

Rollup of 10 pull requests #67828

Merged

bors merged commit 1a4f6b8 into rust-lang:master Jan 3, 2020

ohadravid deleted the impl-trait-does-not-live-long-enough branch January 3, 2020 18:59

estebank mentioned this pull request Jan 6, 2020

Do not suggest adding a new lifetime bound in returned impl Trait if 'static is already specified in the signature #67910

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Suggest adding a lifetime constraint for opaque type #67595

Suggest adding a lifetime constraint for opaque type #67595

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Suggest adding a lifetime constraint for opaque type #67595

Suggest adding a lifetime constraint for opaque type #67595

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