Check yield terminator's resume type in borrowck
In borrowck, we didn't check that the lifetimes of the `TerminatorKind::Yield`'s `resume_place` were actually compatible with the coroutine's signature. That means that the lifetimes were totally going unchecked. Whoops!
This PR implements this checking.
Fixes#119564
r? types
Remove `-Zdump-mir-spanview`
The `-Zdump-mir-spanview` flag was added back in #76074, as a development/debugging aid for the initial work on what would eventually become `-Cinstrument-coverage`. It causes the compiler to emit an HTML file containing a function's source code, with various spans highlighted based on the contents of MIR.
When the suggestion was made to [triage and remove unnecessary `-Z` flags (Zulip)](https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler/topic/.60-Z.60.20option.20triage), I noted that this flag could potentially be worth removing, but I wanted to keep it around to see whether I found it useful for my own coverage work.
But when I actually tried to use it, I ran into various issues (e.g. it crashes on `tests/coverage/closure.rs`). If I can't trust it to work properly without a full overhaul, then instead of diving down a rabbit hole of trying to fix arcane span-handling bugs, it seems better to just remove this obscure old code entirely.
---
````@rustbot```` label +A-code-coverage
rework `-Zverbose`
implements the changes described in https://github.com/rust-lang/compiler-team/issues/706
the first commit is only a name change from `-Zverbose` to `-Zverbose-internals` and does not change behavior. the second commit changes diagnostics.
possible follow up work:
- `ty::pretty` could print more info with `--verbose` than it does currently. `-Z verbose-internals` shows too much info in a way that's not helpful to users. michael had ideas about this i didn't fully understand: https://rust-lang.zulipchat.com/#narrow/stream/233931-t-compiler.2Fmajor-changes/topic/uplift.20some.20-Zverbose.20calls.20and.20rename.20to.E2.80.A6.20compiler-team.23706/near/408984200
- `--verbose` should imply `-Z write-long-types-to-disk=no`. the code in `ty_string_with_limit` should take `--verbose` into account (apparently this affects `Ty::sort_string`, i'm not familiar with this code). writing a file to disk should suggest passing `--verbose`.
r? `@compiler-errors` cc `@estebank`
Make closures carry their own ClosureKind
Right now, we use the "`movability`" field of `hir::Closure` to distinguish a closure and a coroutine. This is paired together with the `CoroutineKind`, which is located not in the `hir::Closure`, but the `hir::Body`. This is strange and redundant.
This PR introduces `ClosureKind` with two variants -- `Closure` and `Coroutine`, which is put into `hir::Closure`. The `CoroutineKind` is thus removed from `hir::Body`, and `Option<Movability>` no longer needs to be a stand-in for "is this a closure or a coroutine".
r? eholk
Split coroutine desugaring kind from source
What a coroutine is desugared from (gen/async gen/async) should be separate from where it comes (fn/block/closure).
`IntoDiagnostic` defaults to `ErrorGuaranteed`, because errors are the
most common diagnostic level. It makes sense to do likewise for the
closely-related (and much more widely used) `DiagnosticBuilder` type,
letting us write `DiagnosticBuilder<'a, ErrorGuaranteed>` as just
`DiagnosticBuilder<'a>`. This cuts over 200 lines of code due to many
multi-line things becoming single line things.
detects redundant imports that can be eliminated.
for #117772 :
In order to facilitate review and modification, split the checking code and
removing redundant imports code into two PR.
coverage: Use `SpanMarker` to improve coverage spans for `if !` expressions
Coverage instrumentation works by extracting source code spans from MIR. However, some kinds of syntax are effectively erased during MIR building, so their spans don't necessarily exist anywhere in MIR, making them invisible to the coverage instrumentor (unless we resort to various heuristics and hacks to recover them).
This PR introduces `CoverageKind::SpanMarker`, which is a new variant of `StatementKind::Coverage`. Its sole purpose is to represent spans that would otherwise not appear in MIR, so that the coverage instrumentor can extract them.
When coverage is enabled, the MIR builder can insert these dummy statements as needed, to improve the accuracy of spans used by coverage mappings.
Fixes#115468.
---
```@rustbot``` label +A-code-coverage
There are cases where coverage instrumentation wants to show a span for some
syntax element, but there is no MIR node that naturally carries that span, so
the instrumentor can't see it.
MIR building can now use this new kind of coverage statement to deliberately
include those spans in MIR, attached to a dummy statement that has no other
effect.
By default, `newtype_index!` types get a default `Encodable`/`Decodable`
impl. You can opt out of this with `custom_encodable`. Opting out is the
opposite to how Rust normally works with autogenerated (derived) impls.
This commit inverts the behaviour, replacing `custom_encodable` with
`encodable` which opts into the default `Encodable`/`Decodable` impl.
Only 23 of the 59 `newtype_index!` occurrences need `encodable`.
Even better, there were eight crates with a dependency on
`rustc_serialize` just from unused default `Encodable`/`Decodable`
impls. This commit removes that dependency from those eight crates.
Expand Miri's BorTag GC to a Provenance GC
As suggested in https://github.com/rust-lang/miri/issues/3080#issuecomment-1732505573
We previously solved memory growth issues associated with the Stacked Borrows and Tree Borrows runtimes with a GC. But of course we also have state accumulation associated with whole allocations elsewhere in the interpreter, and this PR starts tackling those.
To do this, we expand the visitor for the GC so that it can visit a BorTag or an AllocId. Instead of collecting all live AllocIds into a single HashSet, we just collect from the Machine itself then go through an accessor `InterpCx::is_alloc_live` which checks a number of allocation data structures in the core interpreter. This avoids the overhead of all the inserts that collecting their keys would require.
r? ``@RalfJung``
Note about object lifetime defaults in does not live long enough error
This is a aspect of Rust that frequently trips up people who are not aware of it yet. This diagnostic attempts to explain what's happening and why the lifetime constraint, that was never mentioned in the source, arose.
The implementation feels a bit questionable, I'm not sure whether there are better ways to do this. There probably are.
fixes#117835
r? types
interpret: simplify handling of shifts by no longer trying to handle signed and unsigned shift amounts in the same branch
While we're at it, also update comments in codegen and MIR building related to shifts, and fix the overflow error printed by Miri on negative shift amounts.
