Gracefully fail to resolve associated items instead of `delay_span_bug`.
`codegen_fulfill_obligation` is used during instance resolution for trait items.
In case of insufficient normalization issues during MIR inlining, it caused ICEs.
It's better to gracefully refuse to resolve the associated item, and let the caller decide what to do with this.
Split from https://github.com/rust-lang/rust/pull/91743Closes#69121Closes#73021Closes#88599Closes#93008Closes#93248Closes#94680Closes#96170
r? `@oli-obk`
tighten sanity checks around Scalar and ScalarPair
While investigating https://github.com/rust-lang/rust/issues/96185 I noticed codegen has tighter sanity checks here than Miri does, so I added some more assertions. Strangely, some of them fail, so I also needed to add a HACK... that is probably worth looking into.
This does not fix that issue, but it changes the ICE messages, making it quite clear that we have a scalar whose size is not the same as that of the surrounding layout.
r? `@oli-obk`
logging: add env var to control verbose scope entry/exit logging
~~This got removed in https://github.com/rust-lang/rust/pull/75143, and I find this makes long traces a lot harder to read, so I propose we add this back.~~
Example trace:
```
│ │ ├─0ms INFO rustc_const_eval::interpret::step return
│ │ ├─0ms INFO rustc_const_eval::interpret::eval_context popping stack frame (returning from function)
│ │┌┘rustc_const_eval::interpret::eval_context::frame std::ptr::mut_ptr::<impl *mut u8>::guaranteed_eq
│ ├┘rustc_const_eval::interpret::eval_context::frame std::ptr::mut_ptr::<impl *mut u8>::is_null
│ ├─1ms INFO rustc_const_eval::interpret::step // executing bb2
│ ├─1ms INFO rustc_const_eval::interpret::step StorageDead(_4)
│ ├─1ms INFO rustc_const_eval::interpret::step StorageDead(_2)
│ ├─1ms INFO rustc_const_eval::interpret::step return
│ ├─1ms INFO rustc_const_eval::interpret::eval_context popping stack frame (returning from function)
│┌┘rustc_const_eval::interpret::eval_context::frame std::ptr::mut_ptr::<impl *mut u8>::is_null
├┘rustc_const_eval::interpret::eval_context::frame std::sys_common::thread_local_dtor::register_dtor_fallback::run_dtors
├─178ms INFO rustc_const_eval::interpret::step // executing bb2
├─178ms INFO rustc_const_eval::interpret::step StorageDead(_5)
```
r? `@oli-obk`
Fix inaccurate function name in `rustc_const_eval` docs
Looks to me like this fixes#85513. I had trouble making a intra-docs link to `eval_place_to_op` work, though...
Use lifetimes on type-alias-impl-trait used in function signatures to infer output type lifetimes
fixes https://github.com/rust-lang/rust/issues/96564
TLDR:
```rust
fn execute(ty: Ty<'_>) -> &str { todo!() }
```
(`Ty` being a type alias impl trait) used to produce the following error before this PR
```
error[E0581]: return type references an anonymous lifetime, which is not constrained by the fn input types
--> src/lib.rs:4:27
|
4 | fn execute(ty: Ty<'_>) -> &str { todo!() }
| ^^^^
|
= note: lifetimes appearing in an associated type are not considered constrained
```
Remove hacks in `make_token_stream`.
`make_tokenstream` has three commented hacks, and a comment at the top
referring to #67062. These hacks have no observable effect, at least as judged
by running the test suite. The hacks were added in #82608, with an explanation
[here](https://github.com/rust-lang/rust/pull/82608#issuecomment-812877329). It
appears that one of the following is true: (a) they never did anything useful,
(b) they do something useful but we have no test coverage for them, or (c)
something has changed in the meantime that means they are no longer necessary.
This commit removes the hacks and the comments, in the hope that (b) is not
true.
r? `@Aaron1011`
Use `FxIndexSet` to avoid sorting fake borrows
This fixes#96449, but I haven't yet been able to
make the reproducer work using `#[cfg]` attributes,
so we can't use the 'revision' infra to write a test
The previous implementation relied on sorting by `PlaceRef`.
This requires sorting by a `DefId`, which uses untracked state
(see #93315)
Handle mismatched generic param kinds in trait impls betterly
- Check that generic params on a generic associated type are the same as in the trait definition
- Check that const generics are not used in place of type generics (and the other way round too)
r? `@lcnr`
Check hidden types for well formedness at the definition site instead of only at the opaque type itself
work towards #90409 . We'll need to look into closure and generator bodies of closures and generators nested inside the hidden type in order to fix that. In hindsight this PR is not necessary for that, but it may be a bit easier with it and we'll get better diagnostics from it on its own.
make sure ScalarPair enums have ScalarPair variants; add some layout sanity checks
`@eddyb` suggested that it might be reasonable for `ScalarPair` enums to simply adjust the ABI of their variants accordingly, such that the layout invariant Miri expects actually holds. This PR implements that. I should note though that I don't know much about this layout computation code and what non-Miri consumers expect from it, so tread with caution!
I also added a function to sanity-check that computed layouts are internally consistent. This helped a lot in figuring out the final shape of this PR, though I am also not 100% sure that these sanity checks are the right ones.
Cc `@oli-obk`
Fixes https://github.com/rust-lang/rust/issues/96221
Properly fix#96638Closes#96638
The main part of this change is `Error::Invalid` now returns both the input and arg indices. However, I realized the code here was kind of confusing and not internally consistent (and thus I was having trouble getting the right behavior). So I've also switched `input_indices` and `arg_indices` to more closely match some naming in `checks` (although I think a more thorough cleanup there could be beneficial). I've added comments, but essentially `input_indices` refers to *user provided* inputs and `arg_indices` refers to *expected* args.
Do not lint on explicit outlives requirements from external macros.
The current implementation of the list rightfully skipped where predicates from external macros.
However, if the where predicate came from the current macro but the bounds were from an external macro, the lint still fired.
Closes https://github.com/rust-lang/rust/issues/96640
This fixes#96449, but I haven't yet been able to
make the reproducer work using `#[cfg]` attributes,
so we can't use the 'revision' infra to write a test
The previous implementation relied on sorting by `PlaceRef`.
This requires sorting by a `DefId`, which uses untracked state
(see #93315)
Fortify handing of where bounds on trait & trait alias definitions
Closes https://github.com/rust-lang/rust/issues/96664
Closes https://github.com/rust-lang/rust/issues/96665
Since https://github.com/rust-lang/rust/pull/93803, when listing all bounds and predicates we now need to account for the possible presence of predicates on any of the generic parameters. Both bugs were hidden by the special handling of bounds at the generic parameter declaration position.
Trait alias expansion used to confuse predicates on `Self` and where predicates.
Exiting too late when listing all the bounds caused a cycle error.
Optimize switch sources representation and usage
* Avoid constructing switch sources unless necessary - switch sources are used by backward analysis with a custom switch int edge effects, but are otherwise unnecessarily computed.
* Use sparse representation of switch sources to avoid quadratic space overhead.
Some subst cleanup
Two separate things here. Both changes are useful for some refactoring I'm doing to add an "EarlyBinder" newtype. (Part of chalkification).
1) Remove `subst_spanned` and just use `subst`. It wasn't used much anyways. In practice, I think we can probably get most of the info just from the actual error message. If not, outputting logs should do the trick. (The specific line probably wouldn't help much anyways).
2) Call `.subst()` before `replace_bound_vars_with_fresh_vars` and `erase_late_bound_regions` in three places that do the opposite. I think there might have been some time in the past that the order here matter for something, but this shouldn't be the case anymore. Conceptually, it makes more sense to the of the *early bound* vars on `fn`s as "outside" the late bound vars.
Actually fix ICE from #96583
PR #96746 fixed a very similar bug, so the same logic is used in a different place.
I originally concluded that the two issues (#96583 and #96738) were identical by comparing the backtrace, but I didn't look close enough.
Warn on unused `#[doc(hidden)]` attributes on trait impl items
[Zulip conversation](https://rust-lang.zulipchat.com/#narrow/stream/266220-rustdoc/topic/.E2.9C.94.20Validy.20checks.20for.20.60.23.5Bdoc.28hidden.29.5D.60).
Whether an associated item in a trait impl is shown or hidden in the documentation entirely depends on the corresponding item in the trait declaration. Rustdoc completely ignores `#[doc(hidden)]` attributes on impl items. No error or warning is emitted:
```rust
pub trait Tr { fn f(); }
pub struct Ty;
impl Tr for Ty { #[doc(hidden)] fn f() {} }
// ^^^^^^^^^^^^^^ ignored by rustdoc and currently
// no error or warning issued
```
This may lead users to the wrong belief that the attribute has an effect. In fact, several such cases are found in the standard library (I've removed all of them in this PR).
There does not seem to exist any incentive to allow this in the future either: Impl'ing a trait for a type means the type *fully* conforms to its API. Users can add `#[doc(hidden)]` to the whole impl if they want to hide the implementation or add the attribute to the corresponding associated item in the trait declaration to hide the specific item. Hiding an implementation of an associated item does not make much sense: The associated item can still be found on the trait page.
This PR emits the warn-by-default lint `unused_attribute` for this case with a future-incompat warning.
`@rustbot` label T-compiler T-rustdoc A-lint
