Fix implied outlives bounds logic for projections
The logic here is subtly wrong. I put a bit of an explanation in a767d7b5165cea8ee5cbe494a4a636c50ef67c9c.
TL;DR: we register outlives predicates to be proved, because wf code normalizes projections (from the unnormalized types) to type variables. This causes us to register those as constraints instead of implied. This was "fine", because we later added that implied bound in the normalized type, and delayed registering constraints. When I went to cleanup `free_region_relations` to *not* delay adding constraints, this bug was uncovered.
cc. `@aliemjay` because this caused your test failure in #99832 (I only realized as I was writing this)
r? `@nikomatsakis`
Implement some tweaks in the new solver
I've been testing the new solver on some small codebases, and these are a few small changes I've needed to make.
The most "controversial" here is implementing `trait_candidate_should_be_dropped_in_favor_of`, which I just implemented to always return false. This surprisingly allows some code to compile, without us having to actually decide on any semantics yet.
r? `@rust-lang/initiative-trait-system-refactor`
Terminals supporting the OSC8 Hyperlink Extension can support inline
anchors where the text is user defineable but clicking on it opens a
browser to a specified URLs, just like `<a href="URL">` does in HTML.
https://gist.github.com/egmontkob/eb114294efbcd5adb1944c9f3cb5feda
correctly update goals in the cache
we may want to actually write the response for our goal into the provisional or global cache instead of simply using the result from the last iteration '^^
r? ```@rust-lang/initiative-trait-system-refactor```
Now that the compiler accepts "-Z instrument-xray" option only when
targeting one of the supported targets, make sure to not run the
codegen tests where the compiler will fail.
Like with other compiletests, we don't have access to internals,
so simply hardcode a list of supported architectures here.
This is somewhat important because LLVM enables the pass based on
target architecture, but support by the target OS also matters.
For example, XRay attributes are processed by codegen for macOS
targets, but Apple linker fails to process relocations in XRay
data sections, so the feature as a whole is not supported there
for the time being.
Let's add at least some tests to verify that this option is accepted
and produces expected LLVM attributes. More tests can be added later
with attribute support.
Recognize all bells and whistles that LLVM's XRay pass is capable of.
The always/never settings are a bit dumb without attributes but they're
still there. The default instruction count is chosen by the compiler,
not LLVM pass. We'll do it later.
Make `derive_const` derive properly const-if-const impls
Fixes#107774Fixes#107666
Also fixes rendering of const-if-const bounds in pretty printing.
r? ```@oli-obk``` or ```@fee1-dead```
Remove astconv usage in diagnostic
Fixes#107775
Location of the test sucks, I know, but I needed to put it somewhere 😓
The issue here is that the root cause of the issue has nothing to do with what's being tested, so I couldn't really give it a better name. Oh well.
rustdoc: use a newline instead of `<br>` to format code headers
Since these elements now use `white-space: pre-wrap` since #107615, it's fine to use newlines for formatting, which is smaller and a bit less complicated.
Rename `PointerSized` to `PointerLike`
The old name was unnecessarily vague. This PR renames a nightly language feature that I added, so I don't think it needs any additional approval, though anyone can feel free to speak up if you dislike the rename.
It's still unsatisfying that we don't the user which of {size, alignment} is wrong, but this trait really is just a stepping stone for a more generalized mechanism to create `dyn*`, just meant for nightly testing, so I don't think it really deserves additional diagnostic machinery for now.
Fixes#107696, cc ``@RalfJung``
r? ``@eholk``
Since these elements now use `white-space: pre-wrap` since
784665d4ce, it's fine to use newlines
for formatting, which is smaller and a bit less complicated.
Rollup of 8 pull requests
Successful merges:
- #100599 (Add compiler error E0523 long description and test)
- #107471 (rustdoc: do not include empty default-settings tag in HTML)
- #107555 (Modify existing bounds if they exist)
- #107662 (Turn projections into copies in CopyProp.)
- #107695 (Add test for Future inflating arg size to 3x )
- #107700 (Run the tools builder on all PRs)
- #107706 (Mark 'atomic_mut_ptr' methods const)
- #107709 (Fix problem noticed in PR106859 with char -> u8 suggestion)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Fix problem noticed in PR106859 with char -> u8 suggestion
HN reader `@ayosec` noticed that my #106859 a few weeks back, malfunctions if you have a Unicode escape, the code suggested b'\u{0}' if you tried to use '\u{0}' where a byte should be, when of course b'\u{0}' is not a byte literal, regardless of the codepoint you can't write Unicode escapes in a byte literal at all.
My proposed fix here just checks that the "character" you wrote is fewer than 5 bytes, thus allowing \x7F and similar escapes but conveniently forbidding even the smallest Unicode escape \u{0} before offering the suggestion as before.
I have provided an updated test which includes examples which do and don't work because of this additional rule.
Turn projections into copies in CopyProp.
The current implementation can leave behind projections that are moved out several times.
This PR widens the check to turn such moves into copies: a move out of a projection of a copy is equivalent to a copy of the original projection.
Modify existing bounds if they exist
Fixes#107335.
This implementation is kinda gross but I don't really see a better way to do it.
This primarily does two things: Modifies `suggest_constraining_type_param` to accept a new parameter that indicates a span to be replaced instead of added, if presented, and limit the additive suggestions to either suggest a new bound on an existing bound (see newly added unit test) or add the generics argument if a generics argument wasn't found.
The former change is required to retain the capability to add an entirely new bounds if it was entirely omitted.
r? ``@compiler-errors``
Fix suggestions rendering when the diff span is multiline
Fixes#92741
cc `@estebank`
I think, I finally fixed. I still want to go back and try to clean up the code a bit. I'm open to suggestions.
Some examples of the new suggestions:
```
help: consider removing the borrow
|
2 - &
|
```
```
help: consider removing the borrow
|
2 - &
3 - mut
|
```
```
help: consider removing the borrow
|
2 - &
3 - mut if true { true } else { false }
2 + if true { true } else { false }
|
```
Should we add a test to ensure this behavior doesn't disappear in the future?
There is a distinction between running this on wasm and i686, even though they should be
identical. This technically is not _incorrect_, it's just an unexpected difference, which is
worth investigating, but not for correctness.
Since we're changing a bunch of stuff, necessary to remove some codegen tests
which look for specific things. Also attempting to restart a test which timed out, maybe due to
fastly failing?
This adds one more test that should track improvements to generator
layout, like #62958 and #62575.
In particular, this test highlights suboptimal layout, as the storage
for the argument future is not being reused across its usage as `upvar`,
`local` and `awaitee` (being polled to completion).
make &mut !Unpin not dereferenceable, and Box<!Unpin> not noalias
See https://github.com/rust-lang/unsafe-code-guidelines/issues/381 and [this LLVM discussion](https://discourse.llvm.org/t/interaction-of-noalias-and-dereferenceable/66979). The exact semantics of how `noalias` and `dereferenceable` interact are unclear, and `@comex` found a case of LLVM actually exploiting that ambiguity for optimizations. I think for now we should treat LLVM `dereferenceable` as implying a "fake read" to happen immediately at the top of the function (standing in for the spurious reads that LLVM might introduce), and that fake read is subject to all the usual `noalias` restrictions. This means we cannot put `dereferenceable` on `&mut !Unpin` references as those references can alias with other references that are being read and written inside the function (e.g. for self-referential generators), meaning the fake read introduces aliasing conflicts with those other accesses.
For `&` this is already not a problem due to https://github.com/rust-lang/rust/pull/98017 which removed the `dereferenceable` attribute for other reasons.
Regular `&mut Unpin` references are unaffected, so I hope the impact of this is going to be tiny.
The first commit does some refactoring of the `PointerKind` enum since I found the old code very confusing each time I had to touch it. It doesn't change behavior.
Fixes https://github.com/rust-lang/miri/issues/2714
EDIT: Turns out our `Box<!Unpin>` treatment was incorrect, too, so the PR also fixes that now (in codegen and Miri): we do not put `noalias` on these boxes any more.
Sort Generator `print-type-sizes` according to their yield points
Especially when trying to diagnose runaway future sizes, it might be more intuitive to sort the variants according to the control flow (aka their yield points) rather than the size of the variants.
Refine error spans for "The trait bound `T: Trait` is not satisfied" when passing literal structs/tuples
This PR adds a new heuristic which refines the error span reported for "`T: Trait` is not satisfied" errors, by "drilling down" into individual fields of structs/enums/tuples to point to the "problematic" value.
Here's a self-contained example of the difference in error span:
```rs
struct Burrito<Filling> {
filling: Filling,
}
impl <Filling: Delicious> Delicious for Burrito<Filling> {}
fn eat_delicious_food<Food: Delicious>(food: Food) {}
fn will_type_error() {
eat_delicious_food(Burrito { filling: Kale });
// ^~~~~~~~~~~~~~~~~~~~~~~~~ (before) The trait bound `Kale: Delicious` is not satisfied
// ^~~~ (after) The trait bound `Kale: Delicious` is not satisfied
}
```
(kale is fine, this is just a silly food-based example)
Before this PR, the error span is identified as the entire argument to the generic function `eat_delicious_food`. However, since only `Kale` is the "problematic" part, we can point at it specifically. In particular, the primary error message itself mentions the missing `Kale: Delicious` trait bound, so it's much clearer if this part is called out explicitly.
---
The _existing_ heuristic tries to label the right function argument in `point_at_arg_if_possible`. It goes something like this:
- Look at the broken base trait `Food: Delicious` and find which generics it mentions (in this case, only `Food`)
- Look at the parameter type definitions and find which of them mention `Filling` (in this case, only `food`)
- If there is exactly one relevant parameter, label the corresponding argument with the error span, instead of the entire call
This PR extends this heuristic by further refining the resulting expression span in the new `point_at_specific_expr_if_possible` function. For each `impl` in the (broken) chain, we apply the following strategy:
The strategy to determine this span involves connecting information about our generic `impl`
with information about our (struct) type and the (struct) literal expression:
- Find the `impl` (`impl <Filling: Delicious> Delicious for Burrito<Filling>`)
that links our obligation (`Kale: Delicious`) with the parent obligation (`Burrito<Kale>: Delicious`)
- Find the "original" predicate constraint in the impl (`Filling: Delicious`) which produced our obligation.
- Find all of the generics that are mentioned in the predicate (`Filling`).
- Examine the `Self` type in the `impl`, and see which of its type argument(s) mention any of those generics.
- Examing the definition for the `Self` type, and identify (for each of its variants) if there's a unique field
which uses those generic arguments.
- If there is a unique field mentioning the "blameable" arguments, use that field for the error span.
Before we do any of this logic, we recursively call `point_at_specific_expr_if_possible` on the parent
obligation. Hence we refine the `expr` "outwards-in" and bail at the first kind of expression/impl we don't recognize.
This function returns a `Result<&Expr, &Expr>` - either way, it returns the `Expr` whose span should be
reported as an error. If it is `Ok`, then it means it refined successfull. If it is `Err`, then it may be
only a partial success - but it cannot be refined even further.
---
I added a new test file which exercises this new behavior. A few existing tests were affected, since their error spans are now different. In one case, this leads to a different code suggestion for the autofix - although the new suggestion isn't _wrong_, it is different from what used to be.
This change doesn't create any new errors or remove any existing ones, it just adjusts the spans where they're presented.
---
Some considerations: right now, this check occurs in addition to some similar logic in `adjust_fulfillment_error_for_expr_obligation` function, which tidies up various kinds of error spans (not just trait-fulfillment error). It's possible that this new code would be better integrated into that function (or another one) - but I haven't looked into this yet.
Although this code only occurs when there's a type error, it's definitely not as efficient as possible. In particular, there are definitely some cases where it degrades to quadratic performance (e.g. for a trait `impl` with 100+ generic parameters or 100 levels deep nesting of generic types). I'm not sure if these are realistic enough to worry about optimizing yet.
There's also still a lot of repetition in some of the logic, where the behavior for different types (namely, `struct` vs `enum` variant) is _similar_ but not the same.
---
I think the biggest win here is better targeting for tuples; in particular, if you're using tuples + traits to express variadic-like functions, the compiler can't tell you which part of a tuple has the wrong type, since the span will cover the entire argument. This change allows the individual field in the tuple to be highlighted, as in this example:
```
// NEW
LL | want(Wrapper { value: (3, q) });
| ---- ^ the trait `T3` is not implemented for `Q`
// OLD
LL | want(Wrapper { value: (3, q) });
| ---- ^~~~~~~~~~~~~~~~~~~~~~~~~ the trait `T3` is not implemented for `Q`
```
Especially with large tuples, the existing error spans are not very effective at quickly narrowing down the source of the problem.
Rollup of 5 pull requests
Successful merges:
- #107553 (Suggest std::ptr::null if literal 0 is given to a raw pointer function argument)
- #107580 (Recover from lifetimes with default lifetimes in generic args)
- #107669 (rustdoc: combine duplicate rules in ayu CSS)
- #107685 (Suggest adding a return type for async functions)
- #107687 (Adapt SROA MIR opt for aggregated MIR)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Adapt SROA MIR opt for aggregated MIR
The pass was broken by https://github.com/rust-lang/rust/pull/107267.
This PR extends it to replace:
```
x = Struct { 0: a, 1: b }
y = move? x
```
by assignment between locals
```
x_0 = a
x_1 = b
y_0 = move? x_0
y_1 = move? x_1
```
The improved pass runs to fixpoint, so we can flatten nested field accesses.
Suggest std::ptr::null if literal 0 is given to a raw pointer function argument
Implementation feels a little sus (we're parsing the span for a `0`) but it seems to fall in line the string-expected-found-char condition right above this check, so I think it's fine.
Feedback appreciated on help text? I think it's consistent but it does sound a little awkward maybe?
Fixes#107517
Adds the extended error documentation for E0523 to indicate that the
error is no longer produced by the compiler.
Update the E0464 documentation to include example code that produces the
error.
Remove the error message E0523 from the compiler and replace it with an
internal compiler error.
The code that consumes PointerKind (`adjust_for_rust_scalar` in rustc_ty_utils)
ended up using PointerKind variants to talk about Rust reference types (& and
&mut) anyway, making the old code structure quite confusing: one always had to
keep in mind which PointerKind corresponds to which type. So this changes
PointerKind to directly reflect the type.
This does not change behavior.
don't point at nonexisting code beyond EOF when warning about delims
Previously we would show this:
```
warning: unnecessary braces around block return value
--> /tmp/bad.rs:1:8
|
1 | fn a(){{{
| ^ ^
|
= note: `#[warn(unused_braces)]` on by default
help: remove these braces
|
1 - fn a(){{{
1 + fn a(){{
|
```
which is now hidden in this case.
We would create a span spanning between the pair of redundant {}s but there is only EOF instead of the `}` so we would previously point at nothing. This would cause the debug assertion ice to trigger. I would have loved to just only point at the second delim and say "you can remove that" but I'm not sure how to do that without refactoring the entire diagnostic which seems tricky. :( But given that this does not seem to regress any other tests we have, I think this edge-casey enough be acceptable.
Fixes https://github.com/rust-lang/rust/issues/107423
r? `@compiler-errors`
Especially when trying to diagnose runaway future sizes, it might be
more intuitive to sort the variants according to the control flow
(aka their yield points) rather than the size of the variants.
