Correctly deny late-bound lifetimes from parent in anon consts and TAITs
Reuse the `AnonConstBoundary` scope (introduced in #108553, renamed in this PR to `LateBoundary`) to deny late-bound vars of *all* kinds (ty/const/lifetime) in anon consts and TAITs.
Side-note, but I would like to consolidate this with the error reporting for RPITs (E0657):
c4f25777a0/compiler/rustc_hir_analysis/src/collect/resolve_bound_vars.rs (L733-L754) but the semantics about what we're allowed to capture there are slightly different, so I'm leaving that untouched.
Fixes#115474
Pretty-print argument-position impl trait to name it.
This removes a corner case.
RPIT and TAIT keep having no name, and it would be wrong to use the one in HIR (Ident::empty), so I make this case ICE.
Custom code classes in docs warning
Fixes https://github.com/rust-lang/rust/issues/115938.
This PR does two things:
1. Unless the `custom_code_classes_in_docs` feature is enabled, it will use the old codeblock tag parser.
2. If there is a codeblock tag that starts with a `.`, it will emit a behaviour change warning.
Hopefully this is the last missing part for this feature until stabilization.
Follow-up of https://github.com/rust-lang/rust/pull/110800.
r? `@notriddle`
Detect cycle errors hidden by opaques during monomorphization
Opaque types may reveal to projections, which themselves normalize to opaques. We don't currently normalize when checking that opaques are cyclical, and we may also not know that the opaque is cyclical until monomorphization (see `tests/ui/type-alias-impl-trait/mututally-recursive-overflow.rs`).
Detect cycle errors in `normalize_projection_ty` and report a fatal overflow (in the old solver). Luckily, this is already detected as a fatal overflow in the new solver.
Fixes#112047
rustc_target/riscv: Fix passing of transparent unions with only one non-ZST member
This ensures that `MaybeUninit<T>` has the same ABI as `T` when passed through an `extern "C"` function.
Fixes https://github.com/rust-lang/rust/issues/115481.
r? `@RalfJung`
Don't modify libstd to dump rustc ICEs
Do a much simpler thing and just dump a `std::backtrace::Backtrace` to file.
r? `@estebank` `@oli-obk`
Fixes#115610
This reduces the amount of dependencies pulling in atty.
```
Removing env_logger v0.9.3
```
Signed-off-by: Martin Kröning <martin.kroening@eonerc.rwth-aachen.de>
This reduces the amount of dependencies pulling in atty.
```
Updating colored v2.0.0 -> v2.0.4
Updating tracing-tree v0.2.3 -> v0.2.4
```
Signed-off-by: Martin Kröning <martin.kroening@eonerc.rwth-aachen.de>
This function is now used to check `#[panic_handler]`, `start` lang item, `main`, `#[start]` and intrinsic functions.
The diagnosis produced are now closer to the ones produced by trait/impl method signature mismatch.
Issue discovered in TB: spurious reads are not (yet) possible in a concurrent setting
We discovered a week ago that in general, the current model of TB does not allow spurious reads because although reads provably never invalidate other reads, they migh invalidate writes.
Consider the code
```rs
fn f1(x: &u8) {}
fn f2(y: &mut u8) -> &mut u8 { &mut *y }
let mut data = 0;
let _ = thread::spawn(|| {
f1(&mut data)
};
let _ = thread::spawn(|| {
let y = f2(&mut data);
*y = 42;
});
```
of which one possible interleaving is
```rs
1: retag x (&, protect) // x: [P]Frozen
2: retag y (&mut, protect) // y: [P]Reserved, x: [P]Frozen
1: return f1 // x: [P]Frozen -> Frozen, y: [P]Reserved
2: return f2 // x: Frozen, y: [P]Reserved -> Reserved
2: write y // x: Disabled, y: Active
```
that does not have UB.
Assume enough barriers to force this specific interleaving, and consider that the compiler could choose to insert a spurious read throug `x` during the call to `f1` which would produce
```rs
1: retag x (&, protect) // x: [P]Frozen
2: retag y (&mut, protect) // y: [P]Reserved, x: [P]Frozen
1: spurious read x // x: [P]Frozen, y: [P]Reserved -> [P]Frozen
1: return f1 // x: [P]Frozen -> Frozen, y: [P]Frozen
2: return f2 // x: Frozen, y: [P]Frozen -> Frozen
2: write y // UB
```
Thus the target of the optimization (with a spurious read) has UB when the source did not.
This is bad.
SB is not affected because the code would be UB as early as `retag y`, this happens because we're trying to be a bit more subtle than that, and because the effects of a foreign read on a protected `&mut` bleed outside of the boundaries of the protector. Fortunately we have a fix planned, but in the meantime here are some `#[should_panic]` exhaustive tests to illustrate the issue.
The error message printed by the `#[should_panic]` tests flags the present issue in slightly more general terms: it says that the sequence `retag x (&, protect); retag y (&mut, protect);` produces the configuration `C_source := x: [P]Frozen, x: [P]Reserved`, and that inserting a spurious read through `x` turns it into `C_target := x: [P]Frozen, y: [P]Reserved`.
It then says that `C_source` is distinguishable from `C_target`, which means that there exists a sequence of instructions applied to both that triggers UB in `C_target` but not in `C_source`.
It happens that one such sequence is `1: return f1; 2: return f2; 2: write y;` as shown above, but it is not the only one, as for example the interleaving `1: return f1; 2: write y;` is also problematic.
This occurs because in some interleavings, inserting
a spurious read turns a Reserved into Frozen.
We show here an exhaustive test (including arbitrary unknown
code in two different threads) that makes this issue
observable.
move things out of mir/mod.rs
This moves a bunch of things out of `mir/mod.rs`:
- all const-related stuff to a new file consts.rs
- all statement/place/operand-related stuff to a new file statement.rs
- all pretty-printing related stuff to pretty.rs
`mod.rs` started out with 3100 lines and ends up with 1600. :)
Also there was some pretty-printing stuff in terminator.rs, that also got moved to pretty.rs, and I reordered things in pretty.rs so that it can be grouped by functionality.
Only the commit "use pretty_print_const_value from MIR constant 'extra' printing" has any behavior changes; it resolves the issue of having a fancy and a very crude pretty-printer for `ConstValue`.
r? `@oli-obk`
Rollup of 6 pull requests
Successful merges:
- #112725 (rustdoc-search: add support for type parameters)
- #114941 (Don't resolve generic impls that may be shadowed by dyn built-in impls)
- #115625 (Explain HRTB + infer limitations of old solver)
- #115839 (Bump libc to 0.2.148)
- #115924 (Don't complain on a single non-exhaustive 1-ZST)
- #115946 (panic when encountering an illegal cpumask in thread::available_parallelism)
r? `@ghost`
`@rustbot` modify labels: rollup
