-Znext-solver: adapt overflow rules to avoid breakage
Do not erase overflow constraints if they are from equating the impl header when normalizing[^1].
This should be the minimal change to not break crates depending on the old project behavior of "apply impl constraints while only lazily evaluating any nested goals".
Fixes https://github.com/rust-lang/trait-system-refactor-initiative/issues/70, see https://hackmd.io/ATf4hN0NRY-w2LIVgeFsVg for the reasoning behind this.
Only keeping constraints on overflow for `normalize-to` goals as that's the only thing needed for backcompat. It also allows us to not track the origin of root obligations. The issue with root goals would be something like the following:
```rust
trait Foo {}
trait Bar {}
trait FooBar {}
impl<T: Foo + Bar> FooBar for T {}
// These two should behave the same, rn we can drop constraints for both,
// but if we don't drop `Misc` goals we would only drop the constraints for
// `FooBar` unless we track origins of root obligations.
fn func1<T: Foo + Bar>() {}
fn func2<T: FooBaz>() {}
```
[^1]: mostly, the actual rules are slightly different
r? ``@compiler-errors``
Add check for possible CStr literals in pre-2021
Fixes [#118654](https://github.com/rust-lang/rust/issues/118654)
Adds information to errors caused by possible CStr literals in pre-2021.
The lexer separates `c"str"` into two tokens if the edition is less than 2021, which later causes an error when parsing. This error now has a more helpful message that directs them to information about editions. However, the user might also have written `c "str"` in a later edition, so to not confuse people who _are_ using a recent edition, I also added a note about whitespace.
We could probably figure out exactly which scenario has been encountered by examining spans and editions, but I figured it would be better not to overcomplicate the creation of the error too much.
This is my first code PR and I tried to follow existing conventions as much as possible, but I probably missed something, so let me know!
add more niches to rawvec
Previously RawVec only had a single niche in its `NonNull` pointer. With this change it now has `isize::MAX` niches since half the value-space of the capacity field is never needed, we can't have a capacity larger than isize::MAX.
Adjust the ignore-compare-mode-next-solver for hangs
Some new tests hang, some old tests don't hang.
r? lcnr or anyone in `@rust-lang/initiative-trait-system-refactor`
Use alias-eq in structural normalization
We don't need to register repeated normalizes-to goals in a loop in structural normalize, but instead we can piggyback on the fact that alias-eq will already normalize aliases until they are rigid.
This fixesrust-lang/trait-system-refactor-initiative#78.
r? lcnr
Desugar `yield` in `async gen` correctly, ensure `gen` always returns unit
1. Ensure `async gen` blocks desugar `yield $expr` to `task_context = yield async_gen_ready($expr)`. Previously we were not assigning the `task_context` correctly, meaning that `yield` expressions in async generators returned type `ResumeTy` instead of `()`, and that we were not storing the `task_context` (which is probably unsound if we were reading the old task-context which has an invalidated borrow or something...)
2. Ensure that all `(async?) gen` blocks and `(async?) gen` fns return unit. Previously we were only checking this for `gen fn`, meaning that `gen {}` and `async gen {}` and `async gen fn` were allowed to return values that weren't unit. This is why #119058 was an ICE rather than an E0308.
Fixes#119058.
Fix ICE `ProjectionKinds Deref and Field were mismatched`
Fix#118144
Removed the check that ICEd if the sequence of projection kinds were different across captures. Instead we now sort based only on `Field` projection kinds.
Properly reject `default` on free const items
Fixes#117791.
Technically speaking, this is a breaking change but I doubt it will lead to any real-world regressions (maybe in some macro-trickery crates?). Doing a crater run probably isn't worth it.
adds a column number to `dbg!()`
this would be very nice to have for a few reasons:
1. the rfc, when deciding not to add column numbers to macro, failed to acknowledge any potential ambiguous cases -- such as the one provided in #114910 -- which do exist
2. would be able to consistently and easily jump directly to the `dbg!()` regardless of the sutation
3. takes up, at a maximum, 3 characters of _horizontal_ screen space
fixes#114910
fix: Overlapping spans in delimited meta-vars
Closes#118786
Delimited meta-vars inside of MBE's spans were set to have the same opening and closing position resulting in an ICE when debug assertions were enabled and an error was present in the templated code.
This ensures that the spans do not overlap, whilst still having the spans point at the usage of the meta-var inside the macro definition.
It includes a regression test.
🖤
More expressions correctly are marked to end with curly braces
Fixes#118859, and replaces the mentioned match statement with an exhaustive list, so that this code doesn't get overlooked in the future
Collect lang items from AST, get rid of `GenericBound::LangItemTrait`
r? `@cjgillot`
cc #115178
Looking forward, the work to remove `QPath::LangItem` will also be significantly more difficult, but I plan on doing it as well. Specifically, we have to change:
1. A lot of `rustc_ast_lowering` for things like expr `..`
2. A lot of astconv, since we actually instantiate lang and non-lang paths quite differently.
3. A ton of diagnostics and clippy lints that are special-cased via `QPath::LangItem`
Meanwhile, it was pretty easy to remove `GenericBound::LangItemTrait`, so I just did that here.
Stabilize `type_name_of_val`
Make the following API stable:
```rust
// in core::any
pub fn type_name_of_val<T: ?Sized>(_val: &T) -> &'static str
```
This is a convenience method to get the type name of a value, as opposed to `type_name` that takes a type as a generic.
Const stability is not added because this relies on `type_name` which is also not const. That has a blocking issue https://github.com/rust-lang/rust/issues/97156.
Wording was also changed to direct most of the details to `type_name` so we don't have as much duplicated documentation.
Fixes tracking issue #66359.
There were two main concerns in the tracking issue:
1. Naming: `type_name_of` and `type_name_of_val` seem like the only mentioned options. Differences in opinion here come from `std::mem::{size_of, align_of, size_of_val, align_of_val}`. This PR leaves the name as `type_name_of_val`, but I can change if desired since it is pretty verbose.
2. What this displays for `&dyn`: I don't think that having `type_name_of_val` function resolve those is worth the headache it would be, see https://github.com/rust-lang/rust/issues/66359#issuecomment-1718480774 for some workarounds. I also amended the docs wording to leave it open-ended, in case we have means to change that behavior in the future.
``@rustbot`` label -T-libs +T-libs-api +needs-fcp
r? libs-api
Some cleanup and improvement for invalid ref casting impl
This PR makes some cleanups and improvements to the `invalid_reference_casting` implementation in preparation for linting on new patterns, while reusing most of the logic.
r? `@est31` (feel free to re-assign)
Add all known `target_feature` configs to check-cfg
This PR adds all the known `target_feature` from ~~`rustc_codegen_ssa`~~ `rustc_target` to the well known list of check-cfg.
It does so by moving the list from `rustc_codegen_ssa` to `rustc_target` ~~`rustc_session` (I not sure about this, but some of the moved function take a `Session`)~~, then using it the `fill_well_known` function.
This already proved to be useful since portable-simd had a bad cfg.
cc `@nnethercote` (since we discussed it in https://github.com/rust-lang/rust/pull/118494)
Add -Zunpretty=stable-mir output test
As strongly suggested here https://github.com/rust-lang/rust/pull/118364#issuecomment-1827974148 this adds output test for `-Zunpretty=stable-mir`, added test shows almost all the functionality of the current printer.
r? `@compiler-errors`
