Use an 'approximate' universal upper bound when reporting region errors#73806
Merged
bors merged 1 commit intorust-lang:masterfrom Jul 1, 2020
Merged
Conversation
Fixes rust-lang#67765 When reporting errors during MIR region inference, we sometimes use `universal_upper_bound` to obtain a named universal region that we can display to the user. However, this is not always possible - in a case like `fn foo<'a, 'b>() { .. }`, the only upper bound for a region containing `'a` and `'b` is `'static`. When displaying diagnostics, it's usually better to display *some* named region (even if there are multiple involved) rather than fall back to a generic error involving `'static`. This commit adds a new `approx_universal_upper_bound` method, which uses the lowest-numbered universal region if the only alternative is to return `'static`.
Contributor
|
r? @estebank (rust_highfive has picked a reviewer for you, use r? to override) |
rust-highfive
added
the
S-waiting-on-review
estebank
approved these changes
Jun 27, 2020
Contributor
estebank
left a comment
estebank
left a comment
There was a problem hiding this comment.
The code changes look reasonable and the output improvements are very welcome. I left a couple of nitpicks, but r=me.
Comment on lines
+14
to
+17
| help: to force the closure to take ownership of `a` (and any other referenced variables), use the `move` keyword | ||
| | | ||
| LL | [0].iter().flat_map(|a| [0].iter().map(move |_| &a)); | ||
| | ^^^^^^^^ |
Contributor
There was a problem hiding this comment.
Can we make this one // run-rustfix now?
Contributor
Author
There was a problem hiding this comment.
The suggestion doesn't actually fix it - it just gets the error message back to the original one.
| /// Therefore, this method should only be used in diagnostic code, | ||
| /// where displaying *some* named universal region is better than | ||
| /// falling back to 'static. | ||
| pub(in crate::borrow_check) fn approx_universal_upper_bound(&self, r: RegionVid) -> RegionVid { |
Contributor
There was a problem hiding this comment.
Could we move this to somewhere in src/librustc_mir/borrow_check/diagnostics/ and make it accessible only there?
Contributor
Author
There was a problem hiding this comment.
This method can't easily be moved, since it references private fields in RegionInferenceContext.
Contributor
|
@bors r+ |
Collaborator
|
📌 Commit 517d361 has been approved by |
bors
added
S-waiting-on-bors
Manishearth
added a commit
to Manishearth/rust
that referenced
this pull request
Jun 29, 2020
…upper, r=estebank Use an 'approximate' universal upper bound when reporting region errors Fixes rust-lang#67765 When reporting errors during MIR region inference, we sometimes use `universal_upper_bound` to obtain a named universal region that we can display to the user. However, this is not always possible - in a case like `fn foo<'a, 'b>() { .. }`, the only upper bound for a region containing `'a` and `'b` is `'static`. When displaying diagnostics, it's usually better to display *some* named region (even if there are multiple involved) rather than fall back to a generic error involving `'static`. This commit adds a new `approx_universal_upper_bound` method, which uses the lowest-numbered universal region if the only alternative is to return `'static`.
Manishearth
added a commit
to Manishearth/rust
that referenced
this pull request
Jun 29, 2020
…upper, r=estebank Use an 'approximate' universal upper bound when reporting region errors Fixes rust-lang#67765 When reporting errors during MIR region inference, we sometimes use `universal_upper_bound` to obtain a named universal region that we can display to the user. However, this is not always possible - in a case like `fn foo<'a, 'b>() { .. }`, the only upper bound for a region containing `'a` and `'b` is `'static`. When displaying diagnostics, it's usually better to display *some* named region (even if there are multiple involved) rather than fall back to a generic error involving `'static`. This commit adds a new `approx_universal_upper_bound` method, which uses the lowest-numbered universal region if the only alternative is to return `'static`.
Manishearth
added a commit
to Manishearth/rust
that referenced
this pull request
Jun 30, 2020
…upper, r=estebank Use an 'approximate' universal upper bound when reporting region errors Fixes rust-lang#67765 When reporting errors during MIR region inference, we sometimes use `universal_upper_bound` to obtain a named universal region that we can display to the user. However, this is not always possible - in a case like `fn foo<'a, 'b>() { .. }`, the only upper bound for a region containing `'a` and `'b` is `'static`. When displaying diagnostics, it's usually better to display *some* named region (even if there are multiple involved) rather than fall back to a generic error involving `'static`. This commit adds a new `approx_universal_upper_bound` method, which uses the lowest-numbered universal region if the only alternative is to return `'static`.
Member
Member
|
@bors r- try @rust-timer queue |
Collaborator
|
Awaiting bors try build completion |
bors
added
S-waiting-on-author
Collaborator
|
⌛ Trying commit 517d361 with merge 91c610e689edb8d299333c89cc783cf7b3727b61... |
Collaborator
|
☀️ Try build successful - checks-actions, checks-azure |
Collaborator
|
Queued 91c610e689edb8d299333c89cc783cf7b3727b61 with parent 665190b, future comparison URL. |
Collaborator
|
Finished benchmarking try commit (91c610e689edb8d299333c89cc783cf7b3727b61): comparison url. |
Contributor
Author
|
No perf impact @bors r=estebank |
Collaborator
|
📌 Commit 517d361 has been approved by |
bors
added
S-waiting-on-bors
bors
added a commit
to rust-lang-ci/rust
that referenced
this pull request
Jul 1, 2020
…arth Rollup of 17 pull requests Successful merges: - rust-lang#72071 (Added detailed error code explanation for issue E0687 in Rust compiler.) - rust-lang#72369 (Bring net/parser.rs up to modern up to date with modern rust patterns) - rust-lang#72445 (Stabilize `#[track_caller]`.) - rust-lang#73466 (impl From<char> for String) - rust-lang#73548 (remove rustdoc warnings) - rust-lang#73649 (Fix sentence structure) - rust-lang#73678 (Update Box::from_raw example to generalize better) - rust-lang#73705 (stop taking references in Relate) - rust-lang#73716 (Document the static keyword) - rust-lang#73752 (Remap Windows ERROR_INVALID_PARAMETER to ErrorKind::InvalidInput from Other) - rust-lang#73776 (Move terminator to new module) - rust-lang#73778 (Make `likely` and `unlikely` const, gated by feature `const_unlikely`) - rust-lang#73805 (Document the type keyword) - rust-lang#73806 (Use an 'approximate' universal upper bound when reporting region errors) - rust-lang#73828 (Fix wording for anonymous parameter name help) - rust-lang#73846 (Fix comma in debug_assert! docs) - rust-lang#73847 (Edit cursor.prev() method docs in lexer) Failed merges: r? @ghost
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
8 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Fixes #67765
When reporting errors during MIR region inference, we sometimes use
universal_upper_boundto obtain a named universal region that wecan display to the user. However, this is not always possible - in a
case like
fn foo<'a, 'b>() { .. }, the only upper bound for a regioncontaining
'aand'bis'static. When displaying diagnostics, it'susually better to display some named region (even if there are
multiple involved) rather than fall back to a generic error involving
'static.This commit adds a new
approx_universal_upper_boundmethod, whichuses the lowest-numbered universal region if the only alternative is to
return
'static.