Don't ICE when trying to copy unsized value in const prop
When we have a trivially false where-clause predicate like `Self: Sized` where `Self = dyn Trait`, we sometimes don't throw an error during typeck for an illegal operation such as copying an unsized type.
This, unfortunately, cannot be made into an error (at least not without some migration -- see #95611 for example), but we should at least not ICE, since this function will never actually be reachable from main, for example.
r? `@RalfJung` since I think you added these assertions? but feel free to reassign.
Fixes#102553
Introduce mir::Unevaluated
Previously the distinction between unevaluated constants in the type-system and in mir was not explicit and a little confusing. Probably better to introduce its own type for that.
r? `@lcnr`
interpret: expose generate_stacktrace without full InterpCx
In Miri we sometimes want to emit diagnostics without having a full `&InterpCx` available. To avoid duplicating code, this adds a way to get a stacktrace from an arbitrary slice of interpreter frames, that Miri can use with access to just a thread manager.
On later stages, the feature is already stable.
Result of running:
rg -l "feature.let_else" compiler/ src/librustdoc/ library/ | xargs sed -s -i "s#\\[feature.let_else#\\[cfg_attr\\(bootstrap, feature\\(let_else\\)#"
The `<*const T>::guaranteed_*` methods now return an option for the unknown case
cc https://github.com/rust-lang/rust/issues/53020#issuecomment-1236932443
I chose `0` for "not equal" and `1` for "equal" and left `2` for the unknown case so backends can just forward to raw pointer equality and it works ✨
r? `@fee1-dead` or `@lcnr`
cc `@rust-lang/wg-const-eval`
Normalize before erasing late-bound regions in `equal_up_to_regions`
Normalize erasing regions **first**, before passing the type through a `BottomUpFolder` which erases late-bound regions too.
The root cause of this issue is due to 96d4137dee, which removes a `normalize_erasing_regions` that happens before this call to `equal_up_to_regions`. While reverting that commit might be a fix, I think it was suspicious to be erasing late-bound regions first _then_ normalizing types in the first place in `equal_up_to_regions`.
-----
I am tempted to ask the reviewer to review and `r+` this without a UI test, since the existing issues that I think this fixes are all incredibly difficult to minimize (anything hyper/warp related, given the nature of those libraries 😓) or impossible to reproduce locally (the miri test), namely:
* This recently reported issue with tokio + warp: #101430
* This issue from `@RalfJung` about Miri being broken: #101344
* This additional issue reported in a comment by `@tmandry` (issue with fuchsia + hyper): https://github.com/rust-lang/rust/issues/101344#issuecomment-1235974564
I have locally verified that the repro in #101430 is fixed with this PR, but after a couple of hours of attempting to minimize this error and either failing to actually repro the ICE, or being overwhelmed with the number of traits and functions I need to inline into a UI test, I have basically given up. Thoughts are appreciated on how best to handle this.
r? `@oli-obk` who is at the intersection of MIR and types-related stuff who may be able to give advice 😅
Add a Machine hook for inline assembly
I'm sketching out some support in Miri to "execute" inline assembly. I want this because there are codebases which have very simple inline assembly like hand-written syscall wrappers, and it would be nice to test such code without modification.
r? ``@oli-obk``
Try normalizing types without RevealAll in ParamEnv in MIR validation
Before, the MIR validator used RevealAll in its ParamEnv for type
checking. This could cause false negatives in some cases due to
RevealAll ParamEnvs not always use all predicates as expected here.
Since some MIR passes like inlining use RevealAll as well, keep using
it in the MIR validator too, but when it fails usign RevealAll, also
try the check without it, to stop false negatives.
Fixes#99866
cc ````````@compiler-errors```````` who nicely helped me on zulip
Fix a bunch of typo
This PR will fix some typos detected by [typos].
I only picked the ones I was sure were spelling errors to fix, mostly in
the comments.
[typos]: https://github.com/crate-ci/typos
This PR will fix some typos detected by [typos].
I only picked the ones I was sure were spelling errors to fix, mostly in
the comments.
[typos]: https://github.com/crate-ci/typos
Rework definition of MIR phases to more closely reflect semantic concerns
Implements most of rust-lang/compiler-team#522 .
I tried my best to restrict this PR to the "core" parts of the MCP. In other words, this includes just enough changes to make the new definition of `MirPhase` make sense. That means there are a couple of FIXMEs lying around. Depending on what reviewers prefer, I can either fix them in this PR or send follow up PRs. There are also a couple other refactorings of the `rustc_mir_transform/src/lib.rs` file that I want to do in follow ups that I didn't leave explicit FIXMEs for.
Rollup of 9 pull requests
Successful merges:
- #95376 (Add `vec::Drain{,Filter}::keep_rest`)
- #100092 (Fall back when relating two opaques by substs in MIR typeck)
- #101019 (Suggest returning closure as `impl Fn`)
- #101022 (Erase late bound regions before comparing types in `suggest_dereferences`)
- #101101 (interpret: make read-pointer-as-bytes a CTFE-only error with extra information)
- #101123 (Remove `register_attr` feature)
- #101175 (Don't --bless in pre-push hook)
- #101176 (rustdoc: remove unused CSS selectors for `.table-display`)
- #101180 (Add another MaybeUninit array test with const)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
interpret: make read-pointer-as-bytes a CTFE-only error with extra information
Next step in the reaction to https://github.com/rust-lang/rust/issues/99923. Also teaches Miri to implicitly strip provenance in more situations when transmuting pointers to integers, which fixes https://github.com/rust-lang/miri/issues/2456.
Pointer-to-int transmutation during CTFE now produces a message like this:
```
= help: this code performed an operation that depends on the underlying bytes representing a pointer
= help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
```
r? ``@oli-obk``
Revert let_chains stabilization
This is the revert against master, the beta revert was already done in #100538.
Bumps the stage0 compiler which already has it reverted.
Rollup of 7 pull requests
Successful merges:
- #100898 (Do not report too many expr field candidates)
- #101056 (Add the syntax of references to their documentation summary.)
- #101106 (Rustdoc-Json: Retain Stripped Modules when they are imported, not when they have items)
- #101131 (CTFE: exposing pointers and calling extern fn is just impossible)
- #101141 (Simplify `get_trait_ref` fn used for `virtual_function_elimination`)
- #101146 (Various changes to logging of borrowck-related code)
- #101156 (Remove `Sync` requirement from lint pass objects)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
CTFE: exposing pointers and calling extern fn is just impossible
The remaining "needs RFC" errors are just needlessly confusing, I think -- time to get rid of that error variant. They are anyway only reachable with miri-unleashed (if at all).
r? `@oli-obk`
Before, the MIR validator used RevealAll in its ParamEnv for type
checking. This could cause false negatives in some cases due to
RevealAll ParamEnvs not always use all predicates as expected here.
Since some MIR passes like inlining use RevealAll as well, keep using
it in the MIR validator too, but when it fails usign RevealAll, also
try the check without it, to stop false negatives.
remove an ineffective check in const_prop
Based on https://github.com/rust-lang/rust/pull/100043, only the last two commits are new.
ConstProp has a special check when reading from a local that prevents reading uninit locals. However, if that local flows into `force_allocation`, then no check fires and evaluation proceeds. So this check is not really effective at preventing accesses to uninit locals.
With https://github.com/rust-lang/rust/pull/100043, `read_immediate` and friends always fail when reading uninit locals, so I don't see why ConstProp would need a separate check. Thus I propose we remove it. This is needed to be able to do https://github.com/rust-lang/rust/pull/100085.
extra sanity check against consts pointing to mutable memory
This should be both unreachable and redundant (since we already ensure that validation only reads from read-only memory, when validating consts), but I feel like we cannot be paranoid enough here, and also if this ever fails it'll be a nicer error than the "cannot read from mutable memory" error.
Replace `Body::basic_blocks()` with field access
Since the refactoring in #98930, it is possible to borrow the basic blocks
independently from other parts of MIR by accessing the `basic_blocks` field
directly.
Replace unnecessary `Body::basic_blocks()` method with a direct field access,
which has an additional benefit of borrowing the basic blocks only.
no alignment check during interning
This should fix https://github.com/rust-lang/rust/issues/101034
r? `@oli-obk`
Unfortunately we don't have a self-contained testcase for this problem. I am not sure how it can be triggered...
Diagnostics migr const eval
This PR should eventually contain all diagnostic migrations for the `rustc_const_eval` crate.
r? `@davidtwco`
`@rustbot` label +A-translation
Because `PassMode::Cast` is by far the largest variant, but is
relatively rare.
This requires making `PassMode` not impl `Copy`, and `Clone` is no
longer necessary. This causes lots of sigil adjusting, but nothing very
notable.
Check projection types before inlining MIR
Fixes https://github.com/rust-lang/rust/issues/100550
I'm very unhappy with this solution, having to duplicate MIR validation code, but at least it removes the ICE.
r? `@compiler-errors`
