Provide structured suggestion for `#![feature(foo)]`
```
error: `S2<'_>` is forbidden as the type of a const generic parameter
--> $DIR/lifetime-in-const-param.rs:5:23
|
LL | struct S<'a, const N: S2>(&'a ());
| ^^
|
= note: the only supported types are integers, `bool` and `char`
help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
|
LL + #![feature(adt_const_params)]
|
```
Fix#55941.
```
error: `S2<'_>` is forbidden as the type of a const generic parameter
--> $DIR/lifetime-in-const-param.rs:5:23
|
LL | struct S<'a, const N: S2>(&'a ());
| ^^
|
= note: the only supported types are integers, `bool` and `char`
help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
|
LL + #![feature(adt_const_params)]
|
```
Fix#55941.
add_retag: ensure box-to-raw-ptr casts are preserved for Miri
In https://github.com/rust-lang/rust/pull/122233 I added `retag_box_to_raw` not realizing that we can already do `addr_of_mut!(*bx)` to turn a box into a raw pointer without an intermediate reference. We just need to ensure this information is preserved past the ElaborateBoxDerefs pass.
r? ``@oli-obk``
Making `libcore` decide this is silly; the backend has so much better information about when it's a good idea.
So introduce a new `typed_swap` intrinsic with a fallback body, but replace that implementation for immediates and scalar pairs.
interpret: ensure that Place is never used for a different frame
We store the address where the stack frame stores its `locals`. The idea is that even if we pop and push, or switch to a different thread with a larger number of frames, then the `locals` address will most likely change so we'll notice that problem. This is made possible by some recent changes by `@WaffleLapkin,` where we no longer use `Place` across things that change the number of stack frames.
I made these debug assertions for now, just to make sure this can't cost us any perf.
The first commit is unrelated but it's a one-line comment change so it didn't warrant a separate PR...
r? `@oli-obk`
miri: add some chance to reuse addresses of previously freed allocations
The hope is that this can help us find ABA issues.
Unfortunately this needs rustc changes so I can't easily run the regular benchmark suite. I used `src/tools/miri/tests/pass/float_nan.rs` as a substitute:
```
Before:
Benchmark 1: ./x.py run miri --stage 0 --args src/tools/miri/tests/pass/float_nan.rs --args --edition=2021
Time (mean ± σ): 9.570 s ± 0.013 s [User: 9.279 s, System: 0.290 s]
Range (min … max): 9.561 s … 9.579 s 2 runs
After:
Benchmark 1: ./x.py run miri --stage 0 --args src/tools/miri/tests/pass/float_nan.rs --args --edition=2021
Time (mean ± σ): 9.698 s ± 0.046 s [User: 9.413 s, System: 0.279 s]
Range (min … max): 9.666 s … 9.731 s 2 runs
```
That's a ~1.3% slowdown, which seems fine to me. I have seen a lot of noise in this style of benchmarking so I don't quite trust this anyway; we can make further experiments in the Miri repo after this migrated there.
r? `@oli-obk`
Add tests (and a bit of cleanup) for interior mut handling in promotion and const-checking
Basically these are the parts of https://github.com/rust-lang/rust/pull/121786 that can be salvaged.
r? ``@oli-obk``
MIR printing: print the path of uneval'd const
Currently it just prints `const _` which makes it impossible to say which constant is being referred to.
Also refer to promoteds in a consistent way; previously MIR printing would do
```
promoted[0] in C1: &Option<Cell<i32>> = {
// ...
}
```
Now that should be
```
const C1::promoted[0]: &Option<Cell<i32>> = {
// ...
}
```
We don't seem to have a test for that so I tried it by hand, it seems to work:
```
const main::promoted[12]: &[&str; 3] = {
let mut _0: &[&str; 3];
let mut _1: [&str; 3];
let mut _2: &str;
let mut _3: &str;
let mut _4: &str;
let mut _5: &str;
bb0: {
_3 = const "b";
_2 = &(*_3);
_5 = const "c";
_4 = &(*_5);
_1 = [const "a", move _2, move _4];
_0 = &_1;
return;
}
}
```
Add a tidy check that checks whether the fluent slugs only appear once
As ``````@Nilstrieb`````` said in https://github.com/rust-lang/rust/pull/121828#issuecomment-1972622855:
> Might make sense to have a tidy check that checks whether the fluent slugs only appear once in the source code and lint for that
there's a tidy check already for sorting
We can get the tidy check error:
```
tidy check
tidy error: /path/to/rust/compiler/rustc_const_eval/messages.ftl: message `const_eval_invalid_align` is not used
tidy error: /path/to/rust/compiler/rustc_lint/messages.ftl: message `lint_trivial_untranslatable_diag` is not used
tidy error: /path/to/rust/compiler/rustc_parse/messages.ftl: message `parse_invalid_literal_suffix` is not used
tidy error: /path/to/rust/compiler/rustc_infer/messages.ftl: message `infer_need_type_info_in_coroutine` is not used
tidy error: /path/to/rust/compiler/rustc_passes/messages.ftl: message `passes_expr_not_allowed_in_context` is not used
tidy error: /path/to/rust/compiler/rustc_passes/messages.ftl: message `passes_layout` is not used
tidy error: /path/to/rust/compiler/rustc_parse/messages.ftl: message `parse_not_supported` is not used
```
r? ``````@Nilstrieb``````
Distinguish between library and lang UB in assert_unsafe_precondition
As described in https://github.com/rust-lang/rust/pull/121583#issuecomment-1963168186, `assert_unsafe_precondition` now explicitly distinguishes between language UB (conditions we explicitly optimize on) and library UB (things we document you shouldn't do, and maybe some library internals assume you don't do).
`debug_assert_nounwind` was originally added to avoid the "only at runtime" aspect of `assert_unsafe_precondition`. Since then the difference between the macros has gotten muddied. This totally revamps the situation.
Now _all_ preconditions shall be checked with `assert_unsafe_precondition`. If you have a precondition that's only checkable at runtime, do a `const_eval_select` hack, as done in this PR.
r? RalfJung
