2229: Fix diagnostic issue when using FakeReads in closures
This PR fixes a diagnostic issue caused by https://github.com/rust-lang/rust/pull/82536. A temporary work around was used in this merged PR which involved feature gating the addition of FakeReads introduced as a result of pattern matching in closures.
The fix involves adding an optional closure DefId to ForLet and ForMatchedPlace FakeReadCauses. This DefId will only be added if a closure pattern matches a Place starting with an Upvar.
r? ```@nikomatsakis```
BTree: move blocks around in node.rs
Without changing any names or implementation, reorder some members:
- Move down the ones defined long ago on the demised `struct Root`, to below the definition of their current host `struct NodeRef`.
- Move up some defined on `struct NodeRef` that are interspersed with those defined on `struct Handle`.
- Move up the `correct_…` methods squeezed between the two flavours of `push`.
- Move the unchecked static downcasts (`cast_to_…`) after the upcasts (`forget_`) and the (weirdly named) dynamic downcasts (`force`).
r? ````@Mark-Simulacrum````
Add an unstable --json=unused-externs flag to print unused externs
This adds an unstable flag to print a list of the extern names not used by cargo.
This PR will enable cargo to collect unused dependencies from all units and provide warnings.
The companion PR to cargo is: https://github.com/rust-lang/cargo/pull/8437
The goal is eventual stabilization of this flag in rustc as well as in cargo.
Discussion of this feature is mostly contained inside these threads: #57274#72342#72603
The feature builds upon the internal datastructures added by #72342
Externs are uniquely identified by name and the information is sufficient for cargo.
If the mode is enabled, rustc will print json messages like:
```
{"unused_extern_names":["byteorder","openssl","webpki"]}
```
For a crate that got passed byteorder, openssl and webpki dependencies but needed none of them.
### Q: Why not pass -Wunused-crate-dependencies?
A: See [ehuss's comment here](https://github.com/rust-lang/rust/issues/57274#issuecomment-624839355)
TLDR: it's cleaner. Rust's warning system wasn't built to be filtered or edited by cargo.
Even a basic implementation of the feature would have to change the "n warnings emitted" line that rustc prints at the end.
Cargo ideally wants to synthesize its own warnings anyways. For example, it would be hard for rustc to emit warnings like
"dependency foo is only used by dev targets", suggesting to make it a dev-dependency instead.
### Q: Make rustc emit used or unused externs?
A: Emitting used externs has the advantage that it simplifies cargo's collection job.
However, emitting unused externs creates less data to be communicated between rustc and cargo.
Often you want to paste a cargo command obtained from `cargo build -vv` for doing something
completely unrelated. The message is emitted always, even if no warning or error is emitted.
At that point, even this tiny difference in "noise" matters. That's why I went with emitting unused externs.
### Q: One json msg per extern or a collective json msg?
A: Same as above, the data format should be concise. Having 30 lines for the 30 crates a crate uses would be disturbing to readers.
Also it helps the cargo implementation to know that there aren't more unused deps coming.
### Q: Why use names of externs instead of e.g. paths?
A: Names are both sufficient as well as neccessary to uniquely identify a passed `--extern` arg.
Names are sufficient because you *must* pass a name when passing an `--extern` arg.
Passing a path is optional on the other hand so rustc might also figure out a crate's location from the file system.
You can also put multiple paths for the same extern name, via e.g. `--extern hello=/usr/lib/hello.rmeta --extern hello=/usr/local/lib/hello.rmeta`,
but rustc will only ever use one of those paths.
Also, paths don't identify a dependency uniquely as it is possible to have multiple different extern names point to the same path.
So paths are ill-suited for identification.
### Q: What about 2015 edition crates?
A: They are fully supported.
Even on the 2015 edition, an explicit `--extern` flag is is required to enable `extern crate foo;` to work (outside of sysroot crates, which this flag doesn't warn about anyways).
So the lint would still fire on 2015 edition crates if you haven't included a dependency specified in Cargo.toml using `extern crate foo;` or similar.
The lint won't fire if your sole use in the crate is through a `extern crate foo;` statement, but that's not its job.
For detecting unused `extern crate foo` statements, there is the `unused_extern_crates` lint
which can be enabled by `#![warn(unused_extern_crates)]` or similar.
cc ```@jsgf``` ```@ehuss``` ```@petrochenkov``` ```@estebank```
Fix error codes check run and ensure it will not go unnoticed again
Fixes#83268.
The error codes explanations were not checked anymore. I fixed this issue and also added variables to ensure that this won't happen again (at least not silently).
BTree: no longer search arrays twice to check Ord
A possible addition to / partial replacement of #83147: no longer linearly search the upper bound of a range in the initial portion of the keys we already know are below the lower bound.
- Should be faster: fewer key comparisons at the cost of some instructions dealing with offsets
- Makes code a little more complicated.
- No longer detects ill-defined `Ord` implementations, but that wasn't a publicised feature, and was quite incomplete, and was only done in the `range` and `range_mut` methods.
r? `@Mark-Simulacrum`
Make rust-demangler installable
Adds bootstrap rules to support installing rust-demangler, as an optional, in-tree `extended` tool. It can be included by updating `config.toml`, setting `extended = true`, and then either (a) adding `"rust-demangler"` to the `tools` array, or by enabling `profiler = true`. In other words, it is a _default_ `extended` tool if `profiler = true`.
When compiling with `-Z instrument-coverage`, the coverage reports are
generated by `llvm-cov`. `llvm-cov` includes a built-in demangler for
C++, and an option to supply an alternate demangler. For Rust, we have
`rust-demangler`, currently used in `rustc` coverage tests.
Fuchsia's toolchain for Rust is built via `./x.py install`. Fuchsia is
adding support for Rust coverage, and we need to include the
`rust-demangler` in the installed `bin` directory.
r? `@tmandry`
This is step 2 towards fixing #77548.
In the codegen and codegen-units test suites, the `//` comment markers
were kept in order not to affect any source locations. This is because
these tests cannot be automatically `--bless`ed.
Adds bootstrap rules to support installing rust-demangler.
When compiling with `-Z instrument-coverage`, the coverage reports are
generated by `llvm-cov`. `llvm-cov` includes a built-in demangler for
C++, and an option to supply an alternate demangler. For Rust, we have
`rust-demangler`, currently used in `rustc` coverage tests.
Fuchsia's toolchain for Rust is built via `./x.py install`. Fuchsia is
adding support for Rust coverage, and we need to include the
`rust-demangler` in the installed `bin` directory.
Configured rust-demangler as an in-tree extended tool.
Added tests to support `./x.py test rust-demangler`.
Install with extended tools by default only if `profiler = true`.
Remove nightly features in rustc_type_ir
`rustc_type_ir` will be used as a type library by Chalk, which we want to be able to build on stable, so this PR removes the current nightly features used.
Document "standard" conventions for error messages
These are currently documented in the API guidelines:
https://rust-lang.github.io/api-guidelines/interoperability.html#error-types-are-meaningful-and-well-behaved-c-good-err
I think it makes sense to uplift this guideline (in a milder form) into
std docs. Printing and producing errors is something that even
non-expert users do frequently, so it is useful to give at least some
indication of what a typical error message looks like.
Add an Mmap wrapper to rustc_data_structures
This wrapper implements StableAddress and falls back to directly reading the file on wasm32.
Taken from #83640, which I will close due to the perf regression.
rustdoc: Don't load all extern crates unconditionally
Instead, only load the crates that are linked to with intra-doc links.
This doesn't help very much with any of rustdoc's fundamental issues
with freezing the resolver, but it at least fixes a stable-to-stable
regression, and makes the crate loading model somewhat more consistent
with rustc's. I tested and it unfortunately does not help at all with https://github.com/rust-lang/rust/pull/82496.
Closes https://github.com/rust-lang/rust/issues/68427. Let me know if you want me to open a separate issue for not freezing the resolver.
r? `@petrochenkov` cc `@eddyb` `@ollie27`
tidy: Add ignore-rules for the line length check
This is step 1 towards fixing https://github.com/rust-lang/rust/issues/77548.
This PR contains the `tidy` change from https://github.com/rust-lang/rust/pull/77675. The "ignoring file length unnecessarily" check is temporarily disabled to simplify landing the ignore-rules. This check will be re-enabled in a follow-up PR.
