Rollup of 10 pull requests #129805
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Rollup of 10 pull requests #129805
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Inspired by discussion on rust-lang#129486 this is intended to at least document the current state of the world in a more public location than throughout a series of issues.
Updates the wrapper for 5c4lar/llvm-project@21eddfa.
This keeps it up-to-date by moving from 0.5.6 to 0.5.7. While here I've additionally updated some other wasm-related dependencies in the workspace to keep them up-to-date and try to avoid duplicate versions as well.
Several compiler functions have `Option<!>` for their return type.
That's odd. The only valid return value is `None`, so why is this type
used?
Because it lets you write certain patterns slightly more concisely. E.g.
if you have these common patterns:
```
let Some(a) = f() else { return };
let Ok(b) = g() else { return };
```
you can shorten them to these:
```
let a = f()?;
let b = g().ok()?;
```
Huh.
An `Option` return type typically designates success/failure. How should
I interpret the type signature of a function that always returns (i.e.
doesn't panic), does useful work (modifying `&mut` arguments), and yet
only ever fails? This idiom subverts the type system for a cute
syntactic trick.
Furthermore, returning `Option<!>` from a function F makes things
syntactically more convenient within F, but makes things worse at F's
callsites. The callsites can themselves use `?` with F but should not,
because they will get an unconditional early return, which is almost
certainly not desirable. Instead the return value should be ignored.
(Note that some of callsites of `process_operand`, `process_immedate`,
`process_assign` actually do use `?`, though the early return doesn't
matter in these cases because nothing of significance comes after those
calls. Ugh.)
When I first saw this pattern I had no idea how to interpret it, and it
took me several minutes of close reading to understand everything I've
written above. I even started a Zulip thread about it to make sure I
understood it properly. "Save a few characters by introducing types so
weird that compiler devs have to discuss it on Zulip" feels like a bad
trade-off to me. This commit replaces all the `Option<!>` return values
and uses `else`/`return` (or something similar) to replace the relevant
`?` uses. The result is slightly more verbose but much easier to
understand.
…=fmease rustdoc-json: Add test for `Self` type Inspired by rust-lang#128471, the rustdoc-json suite had no tests in place for the `Self` type. This PR adds one. I've also manually checked locally that this test passes on 29e9248, confirming that adding `clean::Type::SelfTy` didn't change the JSON output. (potentially adding a self type to json (insead of (ab)using generic) is tracked in rust-lang#128522) Updates rust-lang#81359 r? ``````@fmease``````
…-on-wasm32-u-u, r=workingjubilee Document the broken C ABI of `wasm32-unknown-unknown` Inspired by discussion on rust-lang#129486 this is intended to at least document the current state of the world in a more public location than throughout a series of issues.
…d, r=workingjubilee allow BufReader::peek to be called on unsized types rust-lang#128405
…r=lcnr
Simplify some extern providers
Simplifies some extern crate providers:
1. Generalize the `ProcessQueryValue` identity impl to work on non-`Option` types.
2. Allow `ProcessQueryValue` to wrap its output in an `EarlyBinder`, to simplify `explicit_item_bounds`/`explicit_item_super_predicates`.
3. Use `{ table }` and friends more when possible.
…-dead
Remove `Option<!>` return types.
Several compiler functions have `Option<!>` for their return type. That's odd. The only valid return value is `None`, so why is this type used?
Because it lets you write certain patterns slightly more concisely. E.g. if you have these common patterns:
```
let Some(a) = f() else { return };
let Ok(b) = g() else { return };
```
you can shorten them to these:
```
let a = f()?;
let b = g().ok()?;
```
Huh.
An `Option` return type typically designates success/failure. How should I interpret the type signature of a function that always returns (i.e. doesn't panic), does useful work (modifying `&mut` arguments), and yet only ever fails? This idiom subverts the type system for a cute syntactic trick.
Furthermore, returning `Option<!>` from a function F makes things syntactically more convenient within F, but makes things worse at F's callsites. The callsites can themselves use `?` with F but should not, because they will get an unconditional early return, which is almost certainly not desirable. Instead the return value should be ignored. (Note that some of callsites of `process_operand`, `process_immedate`, `process_assign` actually do use `?`, though the early return doesn't matter in these cases because nothing of significance comes after those calls. Ugh.)
When I first saw this pattern I had no idea how to interpret it, and it took me several minutes of close reading to understand everything I've written above. I even started a Zulip thread about it to make sure I understood it properly. "Save a few characters by introducing types so weird that compiler devs have to discuss it on Zulip" feels like a bad trade-off to me. This commit replaces all the `Option<!>` return values and uses `else`/`return` (or something similar) to replace the relevant `?` uses. The result is slightly more verbose but much easier to understand.
r? ````@cjgillot````
…mease Stop using `ty::GenericPredicates` for non-predicates_of queries `GenericPredicates` is a struct of several parts: A list of of an item's own predicates, and a parent def id (and some effects related stuff, but ignore that since it's kinda irrelevant). When instantiating these generic predicates, it calls `predicates_of` on the parent and instantiates its predicates, and appends the item's own instantiated predicates too: https://github.com/rust-lang/rust/blob/acb4e8b6251f1d8da36f08e7a70fa23fc581839e/compiler/rustc_middle/src/ty/generics.rs#L407-L413 Notice how this should result in a recursive set of calls to `predicates_of`... However, `GenericPredicates` is *also* misused by a bunch of *other* queries as a convenient way of passing around a list of predicates. For these queries, we don't ever set the parent def id of the `GenericPredicates`, but if we did, then this would be very easy to mistakenly call `predicates_of` instead of some other intended parent query. Given that footgun, and the fact that we don't ever even *use* the parent def id in the `GenericPredicates` returned from queries like `explicit_super_predicates_of`, It really has no benefit over just returning `&'tcx [(Clause<'tcx>, Span)]`. This PR additionally opts to wrap the results of `EarlyBinder`, as we've tended to use that in the return type of these kinds of queries to properly convey that the user has params to deal with, and it also gives a convenient way of iterating over a slice of things after instantiating.
…ngjubilee f32 docs: define 'arithmetic' operations r? ``@workingjubilee`` Fixes rust-lang#129699
llvm-wrapper: adapt for LLVM API changes No functional changes intended. Updates the wrapper for 5c4lar/llvm-project@21eddfa. ``@rustbot`` label: +llvm-main r? ``@nikic``
…-ld, r=jieyouxu Update the `wasm-component-ld` binary dependency This keeps it up-to-date by moving from 0.5.6 to 0.5.7. While here I've additionally updated some other wasm-related dependencies in the workspace to keep them up-to-date and try to avoid duplicate versions as well.
mark joboet as on vacation I'll be on vacation for about three weeks and won't have much time for reviewing. r? ``@ghost``
rustbot
added
A-meta
|
@bors r+ rollup=never p=10 |
bors
added
S-waiting-on-bors
|
partially merged already in #129809 |
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Successful merges:
Selftype #129123 (rustdoc-json: Add test forSelftype)wasm32-unknown-unknown#129630 (Document the broken C ABI ofwasm32-unknown-unknown)Option<!>return types. #129724 (RemoveOption<!>return types.)ty::GenericPredicatesfor non-predicates_of queries #129725 (Stop usingty::GenericPredicatesfor non-predicates_of queries)wasm-component-ldbinary dependency #129762 (Update thewasm-component-ldbinary dependency)r? @ghost
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