Small error in "introduce explicit lifetime bound" suggestion #81650

estebank · 2021-02-02T01:51:06Z

error[E0311]: the parameter type `T` may not live long enough
  --> src/main.rs:25:11
   |
25 |     scope.spawn(move |_| {
   |           ^^^^^
   |
note: the parameter type `T` must be valid for the anonymous lifetime #2 defined on the function body at 24:1...
  --> src/main.rs:24:1
   |
24 | fn play_with<T: Animal + Send>(scope: &Scope, animal: T) {
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
note: ...so that the type `[closure@src/main.rs:25:17: 27:6]` will meet its required lifetime bounds
  --> src/main.rs:25:11
   |
25 |     scope.spawn(move |_| {
   |           ^^^^^
help: consider introducing an explicit lifetime bound
   |
24 | fn play_with<'a, T: 'a + Animal + Send>(scope: &Scope, animal: T) {
25 |     scope.spawn + 'a(move |_| {
   |

The suggestion has a spurious extra + 'a in line 25 that shouldn't be there.

The text was updated successfully, but these errors were encountered:

0yoyoyo · 2021-02-07T02:31:24Z

@rustbot claim

0yoyoyo · 2021-02-10T10:41:43Z

Should I just remove wrong + 'a in the suggestion? In this case, we have to add explicit lifetime to Scope to resolve the error.
like this:

fn play_with<'a, T: 'a + Animal + Send>(scope: &Scope<'a>, mut animal: T) {
    scope.spawn(move |_| {
        animal.sleep();
    });
}

Just removing + 'a is a little confusing?

estebank · 2021-02-11T01:18:31Z

@0yoyoyo ideally we would indeed suggest what you're proposing, but I can see how it might be hard. If the best we can do is change the structured suggestion with just a help note, let's leave this ticket open to eventually deal with the full suggestion. In order to do the right suggestion you might have to look for all types in the parameter list and look for structs and traits with implicit (not written out) lifetimes and point them out.

0yoyoyo · 2021-02-11T02:05:03Z

@estebank I agree it is difficult. And I think just removing + 'a is enough in the scope of this issue. (I wanted to make sure whether you expect for me to make full suggestion.)
I'll create PR to remove wrong + 'a.

…fetime-error, r=estebank Fix suggestion to introduce explicit lifetime Addresses rust-lang#81650 Error message after fix: ``` error[E0311]: the parameter type `T` may not live long enough --> src/main.rs:25:11 | 24 | fn play_with<T: Animal + Send>(scope: &Scope, animal: T) { | -- help: consider adding an explicit lifetime bound...: `T: 'a +` 25 | scope.spawn(move |_| { | ^^^^^ | note: the parameter type `T` must be valid for the anonymous lifetime #2 defined on the function body at 24:1... --> src/main.rs:24:1 | 24 | fn play_with<T: Animal + Send>(scope: &Scope, animal: T) { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ note: ...so that the type `[closure@src/main.rs:25:17: 27:6]` will meet its required lifetime bounds --> src/main.rs:25:11 | 25 | scope.spawn(move |_| { | ^^^^^ ```

…onymous-lifetime, r=estebank Improve anonymous lifetime note to indicate the target span Improvement for rust-lang#81650 Cc rust-lang#81995 Message after this improvement: (Improve note in the middle) ``` error[E0311]: the parameter type `T` may not live long enough --> src/main.rs:25:11 | 24 | fn play_with<T: Animal + Send>(scope: &Scope, animal: T) { | -- help: consider adding an explicit lifetime bound...: `T: 'a +` 25 | scope.spawn(move |_| { | ^^^^^ | note: the parameter type `T` must be valid for the anonymous lifetime defined on the function body at 24:40... --> src/main.rs:24:40 | 24 | fn play_with<T: Animal + Send>(scope: &Scope, animal: T) { | ^^^^^ note: ...so that the type `[closure@src/main.rs:25:17: 27:6]` will meet its required lifetime bounds --> src/main.rs:25:11 | 25 | scope.spawn(move |_| { | ^^^^^ ``` r? `@estebank`

…onymous-lifetime, r=estebank Improve anonymous lifetime note to indicate the target span Improvement for rust-lang#81650 Cc rust-lang#81995 Message after this improvement: (Improve note in the middle) ``` error[E0311]: the parameter type `T` may not live long enough --> src/main.rs:25:11 | 24 | fn play_with<T: Animal + Send>(scope: &Scope, animal: T) { | -- help: consider adding an explicit lifetime bound...: `T: 'a +` 25 | scope.spawn(move |_| { | ^^^^^ | note: the parameter type `T` must be valid for the anonymous lifetime defined on the function body at 24:40... --> src/main.rs:24:40 | 24 | fn play_with<T: Animal + Send>(scope: &Scope, animal: T) { | ^^^^^ note: ...so that the type `[closure@src/main.rs:25:17: 27:6]` will meet its required lifetime bounds --> src/main.rs:25:11 | 25 | scope.spawn(move |_| { | ^^^^^ ``` r? ``@estebank``

…onymous-lifetime, r=estebank Improve anonymous lifetime note to indicate the target span Improvement for rust-lang#81650 Cc rust-lang#81995 Message after this improvement: (Improve note in the middle) ``` error[E0311]: the parameter type `T` may not live long enough --> src/main.rs:25:11 | 24 | fn play_with<T: Animal + Send>(scope: &Scope, animal: T) { | -- help: consider adding an explicit lifetime bound...: `T: 'a +` 25 | scope.spawn(move |_| { | ^^^^^ | note: the parameter type `T` must be valid for the anonymous lifetime defined on the function body at 24:40... --> src/main.rs:24:40 | 24 | fn play_with<T: Animal + Send>(scope: &Scope, animal: T) { | ^^^^^ note: ...so that the type `[closure@src/main.rs:25:17: 27:6]` will meet its required lifetime bounds --> src/main.rs:25:11 | 25 | scope.spawn(move |_| { | ^^^^^ ``` r? ```@estebank```

…onymous-lifetime, r=estebank Improve anonymous lifetime note to indicate the target span Improvement for rust-lang#81650 Cc rust-lang#81995 Message after this improvement: (Improve note in the middle) ``` error[E0311]: the parameter type `T` may not live long enough --> src/main.rs:25:11 | 24 | fn play_with<T: Animal + Send>(scope: &Scope, animal: T) { | -- help: consider adding an explicit lifetime bound...: `T: 'a +` 25 | scope.spawn(move |_| { | ^^^^^ | note: the parameter type `T` must be valid for the anonymous lifetime defined on the function body at 24:40... --> src/main.rs:24:40 | 24 | fn play_with<T: Animal + Send>(scope: &Scope, animal: T) { | ^^^^^ note: ...so that the type `[closure@src/main.rs:25:17: 27:6]` will meet its required lifetime bounds --> src/main.rs:25:11 | 25 | scope.spawn(move |_| { | ^^^^^ ``` r? ````@estebank````

…onymous-lifetime, r=estebank Improve anonymous lifetime note to indicate the target span Improvement for rust-lang#81650 Cc rust-lang#81995 Message after this improvement: (Improve note in the middle) ``` error[E0311]: the parameter type `T` may not live long enough --> src/main.rs:25:11 | 24 | fn play_with<T: Animal + Send>(scope: &Scope, animal: T) { | -- help: consider adding an explicit lifetime bound...: `T: 'a +` 25 | scope.spawn(move |_| { | ^^^^^ | note: the parameter type `T` must be valid for the anonymous lifetime defined on the function body at 24:40... --> src/main.rs:24:40 | 24 | fn play_with<T: Animal + Send>(scope: &Scope, animal: T) { | ^^^^^ note: ...so that the type `[closure@src/main.rs:25:17: 27:6]` will meet its required lifetime bounds --> src/main.rs:25:11 | 25 | scope.spawn(move |_| { | ^^^^^ ``` r? `````@estebank`````

…onymous-lifetime, r=estebank Improve anonymous lifetime note to indicate the target span Improvement for rust-lang#81650 Cc rust-lang#81995 Message after this improvement: (Improve note in the middle) ``` error[E0311]: the parameter type `T` may not live long enough --> src/main.rs:25:11 | 24 | fn play_with<T: Animal + Send>(scope: &Scope, animal: T) { | -- help: consider adding an explicit lifetime bound...: `T: 'a +` 25 | scope.spawn(move |_| { | ^^^^^ | note: the parameter type `T` must be valid for the anonymous lifetime defined on the function body at 24:40... --> src/main.rs:24:40 | 24 | fn play_with<T: Animal + Send>(scope: &Scope, animal: T) { | ^^^^^ note: ...so that the type `[closure@src/main.rs:25:17: 27:6]` will meet its required lifetime bounds --> src/main.rs:25:11 | 25 | scope.spawn(move |_| { | ^^^^^ ``` r? ``````@estebank``````

0yoyoyo · 2021-03-01T09:48:58Z

@estebank Can this issue be closed?

JohnTitor added the C-bug Category: This is a bug. label Feb 2, 2021

rustbot assigned 0yoyoyo Feb 7, 2021

0yoyoyo mentioned this issue Feb 11, 2021

Fix suggestion to introduce explicit lifetime #81995

Merged

0yoyoyo mentioned this issue Feb 21, 2021

Improve anonymous lifetime note to indicate the target span #82370

Merged

estebank closed this as completed Mar 1, 2021

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Small error in "introduce explicit lifetime bound" suggestion #81650

Small error in "introduce explicit lifetime bound" suggestion #81650

estebank commented Feb 2, 2021 •

edited by rustbot

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0yoyoyo commented Feb 7, 2021

0yoyoyo commented Feb 10, 2021

estebank commented Feb 11, 2021

0yoyoyo commented Feb 11, 2021

0yoyoyo commented Mar 1, 2021

Small error in "introduce explicit lifetime bound" suggestion #81650

Small error in "introduce explicit lifetime bound" suggestion #81650

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estebank commented Feb 2, 2021 • edited by rustbot Loading

0yoyoyo commented Feb 7, 2021

0yoyoyo commented Feb 10, 2021

estebank commented Feb 11, 2021

0yoyoyo commented Feb 11, 2021

0yoyoyo commented Mar 1, 2021

estebank commented Feb 2, 2021 •

edited by rustbot

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