Implement rustc side of report-future-incompat
cc https://github.com/rust-lang/rust/issues/71249
This is an alternative to `@pnkfelix's` initial implementation in https://github.com/pnkfelix/rust/commits/prototype-rustc-side-of-report-future-incompat (mainly because I started working before seeing that branch 😄 ).
My approach outputs the entire original `Diagnostic`, in a way that is compatible with incremental compilation. This is not yet integrated with compiletest, but can be used manually by passing `-Z emit-future-incompat-report` to `rustc`.
Several changes are made to support this feature:
* The `librustc_session/lint` module is moved to a new crate `librustc_lint_defs` (name bikesheddable). This allows accessing lint definitions from `librustc_errors`.
* The `Lint` struct is extended with an `Option<FutureBreakage>`. When present, it indicates that we should display a lint in the future-compat report. `FutureBreakage` contains additional information that we may want to display in the report (currently, a `date` field indicating when the crate will stop compiling).
* A new variant `rustc_error::Level::Allow` is added. This is used when constructing a diagnostic for a future-breakage lint that is marked as allowed (via `#[allow]` or `--cap-lints`). This allows us to capture any future-breakage diagnostics in one place, while still discarding them before they are passed to the `Emitter`.
* `DiagnosticId::Lint` is extended with a `has_future_breakage` field, indicating whether or not the `Lint` has future breakage information (and should therefore show up in the report).
* `Session` is given access to the `LintStore` via a new `SessionLintStore` trait (since `librustc_session` cannot directly reference `LintStore` without a cyclic dependency). We use this to turn a string `DiagnosticId::Lint` back into a `Lint`, to retrieve the `FutureBreakage` data.
Currently, `FutureBreakage.date` is always set to `None`. However, this could potentially be interpreted by Cargo in the future.
I've enabled the future-breakage report for the `ARRAY_INTO_ITER` lint, which can be used to test out this PR. The intent is to use the field to allow Cargo to determine the date of future breakage (as described in [RFC 2834](https://github.com/rust-lang/rfcs/blob/master/text/2834-cargo-report-future-incompat.md)) without needing to parse the diagnostic itself.
cc `@pnkfelix`
Fix#78549
Before #78430, this worked because `specialize_constructor` didn't actually care too much which constructor was passed to it unless needed. That PR however handles `&str` as a special case, and I did not anticipate patterns for the `&str` type other than string literals.
I am not very confident there are not other similar oversights left, but hopefully only `&str` was different enough to break my assumptions.
Fixes https://github.com/rust-lang/rust/issues/78549
Rollup of 6 pull requests
Successful merges:
- #78073 (Add #[inline] to some functions in core::str.)
- #78596 (Fix doc links to std::fmt)
- #78599 (Add note to process::arg[s] that args shouldn't be escaped or quoted)
- #78602 (fix various aliasing issues in the standard library)
- #78603 (expand: Tweak a comment in implementation of `macro_rules`)
- #78621 (Inline Default::default() for atomics)
Failed merges:
r? `@ghost`
expand: Tweak a comment in implementation of `macro_rules`
The answer to the removed FIXME is that we don't apply mark to the span `sp` just because that span is no longer used. We could apply it, but that would just be unnecessary extra work.
The comments in code tell why the span is unused, it's a span of `$var` literally, which is lost for `tt` variables because their tokens are outputted directly, but kept for other variables which are outputted as [groups](https://doc.rust-lang.org/nightly/proc_macro/struct.Group.html) and `sp` is kept as the group's span.
Closes https://github.com/rust-lang/rust/issues/2887
rustc_llvm: unwrap LLVMMetadataRef before casting
Directly casting the opaque pointer was [reported] to cause an
"incomplete type" error with GCC 9.3:
```
llvm-wrapper/RustWrapper.cpp:939:31: required from here
/usr/include/c++/9.3/type_traits:1301:12: error: invalid use of incomplete type 'struct LLVMOpaqueMetadata'
1301 | struct is_base_of
| ^~~~~~~~~~
In file included from [...]/rust/src/llvm-project/llvm/include/llvm-c/BitReader.h:23,
from llvm-wrapper/LLVMWrapper.h:1,
from llvm-wrapper/RustWrapper.cpp:1:
[...]/rust/src/llvm-project/llvm/include/llvm-c/Types.h:89:16: note: forward declaration of 'struct LLVMOpaqueMetadata'
89 | typedef struct LLVMOpaqueMetadata *LLVMMetadataRef;
| ^~~~~~~~~~~~~~~~~~
```
[reported]: https://zulip-archive.rust-lang.org/182449tcompilerhelp/12215halprustcllvmbuildfail.html#214915124
A simple `unwrap` fixes the issue.
r? `@eddyb`
Suggest calling associated `fn` inside `trait`s
When calling a function that doesn't exist inside of a trait's
associated `fn`, and another associated `fn` in that trait has that
name, suggest calling it with the appropriate fully-qualified path.
Expand the label to be more descriptive.
Prompted by the following user experience:
https://users.rust-lang.org/t/cannot-find-function/50663
Before #78430, string literals worked because `specialize_constructor`
didn't actually care too much which constructor was passed to it unless
needed. Since then, string literals are special cased and a bit hacky. I
did not anticipate patterns for the `&str` type other than string
literals, hence this bug. This makes string literals less hacky.
The validator in visit_local asserts that local has a stroage when used,
but visit_local is never called so validation is ineffective.
Use super_statement and super_terminator to ensure that locals are visited.
The previous recursive approach might overflow the stack when walking a
particularly deep, list-like, graph. In particular, dominator
calculation for borrow checking does such a traversal and very long
functions might lead to a region dependency graph with in this
problematic structure.
This lets rustc users tweak whether the linker should relax ELF relocations,
namely whether it should emit R_X86_64_GOTPCRELX relocations instead of
R_X86_64_GOTPCREL, as the former is allowed by the ABI to be further
optimised. The default value is whatever the target defines.
- Add more well-known traits
- Use the correct binders when lowering trait objects
- Use correct substs when lowering trait objects
- Use the correct binders for opaque_ty_data
- Lower negative impls with the correct polarity
- Supply associated type values
- Use `predicates_defined_on` for where clauses
Avoid BorrowMutError with RUSTC_LOG=debug
```console
$ touch empty.rs
$ env RUSTC_LOG=debug rustc +stage1 --crate-type=lib empty.rs
```
Fails with a `BorrowMutError` because source map files are already
borrowed while `features_query` attempts to format a log message
containing a span.
Release the borrow before the query to avoid the issue.
Simplify a nested bool match
Logically this first eliminates the innermost match by merging the patterns.
Then, in a second step, turns the newly innermost match into a `matches!` call.
Always record reference to binding in match if guards
When encountering a binding from a `match` pattern in its `if` guard when computing a generator's interior types, we must always record the type of a reference to the binding because of how `if` guards are lowered to MIR. This was missed in #75213 because the binding in that test case was autorefed and we recorded that adjusted type anyway.
Fixes#78366
