Robustify and genericize return-type-notation resolution in resolve_bound_vars
#132047
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| if let Some(parent_id) = opt_parent_item { | ||
| self.tcx.local_def_id_to_hir_id(parent_id) | ||
| } else { | ||
| continue; |
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just to make sure I'm following the logic correctly ...
On this branch, next_scope is still None (right?), and therefore this continue will end up sending a None up into the while let Some(current_scope) condition, which means that this continue effectively ends up acting like ... a break?
(But then ... why not just write break here?)
((Having said that, there's nothing wrong here that I can see. I was just trying to figure out if I misunderstood something and that this would not end up behaving just like a break would...))
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Yeah, it doesn't really matter. I can change it to a break for clarity I guess.
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In other methods, we prefer scope not being an option, and breaking when getting to Root. Do you mind making this a bit more uniform?
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…=pnkfelix Robustify and genericize return-type-notation resolution in `resolve_bound_vars` rust-lang#129629 implemented return-type-notation (RTN) in its path form, like `where T::method(..): Bound`. As part of lowering, we must record the late-bound vars for the where clause introduced by the method (namely, its early- and late-bound lifetime arguments, since `where T::method(..)` turns into a higher-ranked where clause over all of the lifetimes according to [RFC 3654](https://rust-lang.github.io/rfcs/3654-return-type-notation.html#converting-to-higher-ranked-trait-bounds)). However, this logic was only looking at the where clauses of the parent item that the `T::method(..)` bound was written on, and not any parent items. This PR generalizes that logic to look at the parent item (i.e. the outer impl or trait) instead and fixes a (debug only) assertion as an effect. This logic is also more general and likely easier to adapt to more interesting (though likely very far off) cases like non-lifetime binder `for<T: Trait> T::method(..): Send` bounds. Tracking: - rust-lang#109417
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@rustbot ready Could use another review for the commit on top. I forgot that we can have self type bounds not from the supertraits, but from the trait self, like: The PR simplifies the logic a bit to account for that case. |
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Felix said he's gone for a week, so r? compiler |
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r? compiler |
cjgillot
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Nov 26, 2024
| if let Some(parent_id) = opt_parent_item { | ||
| self.tcx.local_def_id_to_hir_id(parent_id) | ||
| } else { | ||
| continue; |
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In other methods, we prefer scope not being an option, and breaking when getting to Root. Do you mind making this a bit more uniform?
| if Some(&second_bound) != one_bound.as_ref() { | ||
| self.tcx.dcx().span_delayed_bug( | ||
| path.span, | ||
| "ambiguous resolution for RTN path", |
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For my own culture, where should the proper error be emitted?
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It will error when we probe for the bound in astconv (HIR -> middle).
| let Some((bound_vars, assoc_item)) = one_bound else { | ||
| self.tcx | ||
| .dcx() | ||
| .span_delayed_bug(path.span, "no resolution for RTN path"); |
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Likewise, where should this error?
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Likewise, it will error when we probe for the bound in astconv (HIR -> middle).
| }, | ||
| ) | ||
| .fuse() | ||
| } |
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I wonder how hard it would be to reuse the method probing code we have in rustc_hir_typeck.
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I think it would be pretty difficult to do without inducing cycles, since the lowering code requires lowering trait refs.
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☔ The latest upstream changes (presumably #132894) made this pull request unmergeable. Please resolve the merge conflicts. |
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r? @cjgillot, could you perhaps take another look at this? otherwise, please re-roll. |
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…jgillot Robustify and genericize return-type-notation resolution in `resolve_bound_vars` rust-lang#129629 implemented return-type-notation (RTN) in its path form, like `where T::method(..): Bound`. As part of lowering, we must record the late-bound vars for the where clause introduced by the method (namely, its early- and late-bound lifetime arguments, since `where T::method(..)` turns into a higher-ranked where clause over all of the lifetimes according to [RFC 3654](https://rust-lang.github.io/rfcs/3654-return-type-notation.html#converting-to-higher-ranked-trait-bounds)). However, this logic was only looking at the where clauses of the parent item that the `T::method(..)` bound was written on, and not any parent items. This PR generalizes that logic to look at the parent item (i.e. the outer impl or trait) instead and fixes a (debug only) assertion as an effect. This logic is also more general and likely easier to adapt to more interesting (though likely very far off) cases like non-lifetime binder `for<T: Trait> T::method(..): Send` bounds. Tracking: - rust-lang#109417
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The job Click to see the possible cause of the failure (guessed by this bot) |
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💔 Test failed - checks-actions |
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…iaskrgr Rollup of 8 pull requests Successful merges: - rust-lang#128184 (std: refactor `pthread`-based synchronization) - rust-lang#132047 (Robustify and genericize return-type-notation resolution in `resolve_bound_vars`) - rust-lang#133515 (fix: hurd build, stat64.st_fsid was renamed to st_dev) - rust-lang#133602 (fix: fix codeblocks in `PathBuf` example) - rust-lang#133622 (update link to "C++ Exceptions under the hood" blog) - rust-lang#133660 (Do not create trait object type if missing associated types) - rust-lang#133686 (Add diagnostic item for `std::ops::ControlFlow`) - rust-lang#133689 (Fixed typos by changing `happend` to `happened`) r? `@ghost` `@rustbot` modify labels: rollup
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Rollup merge of rust-lang#132047 - compiler-errors:rbv-rtn-cleanup, r=cjgillot Robustify and genericize return-type-notation resolution in `resolve_bound_vars` rust-lang#129629 implemented return-type-notation (RTN) in its path form, like `where T::method(..): Bound`. As part of lowering, we must record the late-bound vars for the where clause introduced by the method (namely, its early- and late-bound lifetime arguments, since `where T::method(..)` turns into a higher-ranked where clause over all of the lifetimes according to [RFC 3654](https://rust-lang.github.io/rfcs/3654-return-type-notation.html#converting-to-higher-ranked-trait-bounds)). However, this logic was only looking at the where clauses of the parent item that the `T::method(..)` bound was written on, and not any parent items. This PR generalizes that logic to look at the parent item (i.e. the outer impl or trait) instead and fixes a (debug only) assertion as an effect. This logic is also more general and likely easier to adapt to more interesting (though likely very far off) cases like non-lifetime binder `for<T: Trait> T::method(..): Send` bounds. Tracking: - rust-lang#109417
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#129629 implemented return-type-notation (RTN) in its path form, like
where T::method(..): Bound. As part of lowering, we must record the late-bound vars for the where clause introduced by the method (namely, its early- and late-bound lifetime arguments, sincewhere T::method(..)turns into a higher-ranked where clause over all of the lifetimes according to RFC 3654).However, this logic was only looking at the where clauses of the parent item that the
T::method(..)bound was written on, and not any parent items. This PR generalizes that logic to look at the parent item (i.e. the outer impl or trait) instead and fixes a (debug only) assertion as an effect.This logic is also more general and likely easier to adapt to more interesting (though likely very far off) cases like non-lifetime binder
for<T: Trait> T::method(..): Sendbounds.Tracking: