Rollup of 11 pull requests
Successful merges:
- #75853 (Use more intra-doc-links in `core::fmt`)
- #75928 (Remove trait_selection error message in specific case)
- #76329 (Add check for doc alias attribute at crate level)
- #77219 (core::global_allocator docs link to std::alloc::GlobalAlloc)
- #77395 (BTreeMap: admit the existence of leaf edges in comments)
- #77407 (Improve build-manifest to work with the improved promote-release)
- #77426 (Include scope id in SocketAddrV6::Display)
- #77439 (Fix missing diagnostic span for `impl Trait` with const generics, and add various tests for `min_const_generics` and `const_generics`)
- #77471 (BTreeMap: refactoring around edges, missed spots)
- #77512 (Allow `Abort` terminators in all const-contexts)
- #77514 (Replace some once(x).chain(once(y)) with [x, y] IntoIter)
Failed merges:
r? `@ghost`
Allow `Abort` terminators in all const-contexts
We never unwind during const-eval, so we basically have these semantics already. Also I just figured out that these only appear along the cleanup path, which doesn't get const-checked. In other words, this doesn't actually change behavior: the `check-pass` test I added compiles just fine on nightly.
r? @RalfJung
cc @rust-lang/wg-const-eval
Use `tracing` spans to trace the entire MIR interp stack
r? @RalfJung
While being very verbose, this allows really good tracking of what's going on. While I considered schemes like the previous indenter that we had (which we could get by using the `tracing-tree` crate), this will break down horribly with things like multithreaded rustc. Instead, we can now use `RUSTC_LOG` to restrict the things being traced. You could specify a filter in a way that only shows the logging of a specific frame.
If we lower the span's level to `debug`, then in `info` level logging we'd not see the frames, but in `debug` level we would see them. The filtering rules in `tracing` are super powerful, but I'm not sure if we can specify a filter so we do see `debug` level events, but *not* the `frame` spans. The documentation at https://docs.rs/tracing-subscriber/0.2.10/tracing_subscriber/struct.EnvFilter.html makes me think that we can only turn on things, not turn off things at a more precise level.
cc @hawkw
The destination propagation as currently implemented does not supersede
the NRVO, e.g., the destination propagation never applies if either
local has an address taken, while NRVO might.
Additionally, the issue with failing assertions had been already
resolved.
Continue running both optimizations at mir-opt-level >= 2.
These appear along the cleanup path inside functions with
`#[unwind(aborts)]`. We don't const-check the cleanup path anyways,
since const-eval already has "abort-on-panic" semantics and there's
often drops that would otherwise be forbidden, so the check wasn't
really preventing anything anyways.
Bypass const_item_mutation if const's type has Drop impl
Follow-up to #75573. This PR disables the const_item_mutation lint in cases that the const has a Drop impl which observes the mutation.
```rust
struct Log { msg: &'static str }
const LOG: Log = Log { msg: "" };
impl Drop for Log {
fn drop(&mut self) { println!("{}", self.msg); }
}
LOG.msg = "wow"; // prints "wow"
```
r? @Aaron1011
Add `-Zprecise-enum-drop-elaboration`
Its purpose is to assist in debugging #77382 and #74551. Passing `-Zprecise-enum-drop-elaboration=no` will turn off the added precision that seems to be causing issues on some platforms. This assumes that we can reproduce #77382 on the latest master. I should have done this earlier. Oh well.
cc @cuviper
r? @pnkfelix
Overhaul const-checking diagnostics
The primary purpose of this PR was to remove `NonConstOp::STOPS_CONST_CHECKING`, which causes any additional errors found by the const-checker to be silenced. I used this flag to preserve diagnostic parity with `qualify_min_const_fn.rs`, which has since been removed.
However, simply removing the flag caused a deluge of errors in some cases, since an error would be emitted any time a local or temporary had a wrong type. To remedy this, I added an alternative system (`DiagnosticImportance`) to silence additional error messages that were likely to distract the user from the underlying issue. When an error of the highest importance occurs, all less important errors are silenced. When no error of the highest importance occurs, all less important errors are emitted after checking is complete. Following the suggestions from the important error is usually enough to fix the less important errors, so this should lead to better UX most of the time.
There's also some unrelated diagnostics improvements in this PR isolated in their own commits. Splitting them out would be possible, but a bit of a pain. This isn't as tidy as some of my other PRs, but it should *only* affect diagnostics, never whether or not something passes const-checking. Note that there are a few trivial exceptions to this, like banning `Yield` in all const-contexts, not just `const fn`.
As always, meant to be reviewed commit-by-commit.
r? `@oli-obk`
adt_destructor by default also validates the Drop impl using
dropck::check_drop_impl, which contains an expect_local(). This
leads to ICE in check_const_item_mutation if the const's type is
not a local type.
thread 'rustc' panicked at 'DefId::expect_local: `DefId(5:4805 ~ alloc[d7e9]::vec::{impl#50})` isn't local', compiler/rustc_span/src/def_id.rs:174:43
stack backtrace:
0: rust_begin_unwind
1: rustc_span::def_id::DefId::expect_local::{{closure}}
2: rustc_typeck::check::dropck::check_drop_impl
3: rustc_middle::ty::util::<impl rustc_middle::ty::context::TyCtxt>::calculate_dtor::{{closure}}
4: rustc_middle::ty::trait_def::<impl rustc_middle::ty::context::TyCtxt>::for_each_relevant_impl
5: rustc_middle::ty::util::<impl rustc_middle::ty::context::TyCtxt>::calculate_dtor
6: rustc_typeck::check::adt_destructor
7: rustc_middle::ty::query::<impl rustc_query_system::query::config::QueryAccessors<rustc_middle::ty::context::TyCtxt> for rustc_middle::ty::query::queries::adt_destructor>::compute
8: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl
9: rustc_query_system::query::plumbing::get_query_impl
10: rustc_mir::transform::check_const_item_mutation::ConstMutationChecker::is_const_item_without_destructor
This helper function was meant to reduce code duplication between
const-checking pre- and post-drop-elaboration. Most of the functionality
is only relevant for the pre-drop-elaboration pass.
