It lints against features that are inteded to be internal to the
compiler and standard library. Implements MCP #596.
We allow `internal_features` in the standard library and compiler as those
use many features and this _is_ the standard library from the "internal to the compiler and
standard library" after all.
Marking some features as internal wasn't exactly the most scientific approach, I just marked some
mostly obvious features. While there is a categorization in the macro,
it's not very well upheld (should probably be fixed in another PR).
We always pass `-Ainternal_features` in the testsuite
About 400 UI tests and several other tests use internal features.
Instead of throwing the attribute on each one, just always allow them.
There's nothing wrong with testing internal features^^
Diagnostic namespace
This PR implements the basic infrastructure for accepting the `#[diagnostic]` attribute tool namespace as specified in https://github.com/rust-lang/rfcs/pull/3368. Note: This RFC is not merged yet, but it seems like it will be accepted soon. I open this PR early on to get feedback on the actual implementation as soon as possible. This hopefully enables getting at least the diagnostic namespace to stable rust "soon", so that crates do not need to bump their MSRV if we stabilize actual attributes in this namespace.
This PR only adds infrastructure accept attributes from this namespace, it does not add any specific attribute. Therefore the compiler will emit a lint warning for each attribute that's actually used. This namespace is added behind a feature flag, so it will be only available on a nightly compiler for now.
cc `@estebank` as they've supported me in planing, specifying and implementing this feature.
enable `rust_2018_idioms` lint group for doctests
With this change, `rust_2018_idioms` lint group will be enabled for compiler/libstd doctests.
Resolves#106086Resolves#99144
Signed-off-by: ozkanonur <work@onurozkan.dev>
Fix the ffi_unwind_calls lint documentation
This fixes the [`ffi_unwind_calls`](https://doc.rust-lang.org/nightly/rustc/lints/listing/allowed-by-default.html#ffi-unwind-calls) documentation to show its output correctly. Currently it is showing the text `{{produces}}` which is not how it should look.
This fixes it by not ignoring the example. I'm not sure why it was ignored, as the way the lint currently works it doesn't seem to require external linkage. This also fixes several mistakes in the example:
* There is no `ffi_unwind_calls` feature.
* Denies the lint (which is otherwise allow be default).
* Removes the `mod impl` which is not valid Rust syntax, and doesn't appear to be needed anyways.
The output now looks like:
```
warning: call to foreign function with FFI-unwind ABI
--> lint_example.rs:10:14
|
10 | unsafe { foo(); }
| ^^^^^ call to foreign function with FFI-unwind ABI
|
note: the lint level is defined here
--> lint_example.rs:2:9
|
2 | #![warn(ffi_unwind_calls)]
| ^^^^^^^^^^^^^^^^
warning: call to function pointer with FFI-unwind ABI
--> lint_example.rs:12:14
|
12 | unsafe { ptr(); }
| ^^^^^ call to function pointer with FFI-unwind ABI
```
This also includes some updates to the lint-docs tool to help with this issue:
* Adds a check if a lint documentation has `{{produces}}` with an ignored example, and generates an error.
* All instances of a lint are now displayed. Previously it only showed the first time the lint fires. Some examples may trigger a lint multiple times, and they are all now displayed.
Ensure `ptr::read` gets all the same LLVM `load` metadata that dereferencing does
I was looking into `array::IntoIter` optimization, and noticed that it wasn't annotating the loads with `noundef` for simple things like `array::IntoIter<i32, N>`. Trying to narrow it down, it seems that was because `MaybeUninit::assume_init_read` isn't marking the load as initialized (<https://rust.godbolt.org/z/Mxd8TPTnv>), which is unfortunate since that's basically its reason to exist.
The root cause is that `ptr::read` is currently implemented via the *untyped* `copy_nonoverlapping`, and thus the `load` doesn't get any type-aware metadata: no `noundef`, no `!range`. This PR solves that by lowering `ptr::read(p)` to `copy *p` in MIR, for which the backends already do the right thing.
Fortuitiously, this also improves the IR we give to LLVM for things like `mem::replace`, and fixes a couple of long-standing bugs where `ptr::read` on `Copy` types was worse than `*`ing them.
Zulip conversation: <https://rust-lang.zulipchat.com/#narrow/stream/219381-t-libs/topic/Move.20array.3A.3AIntoIter.20to.20ManuallyDrop/near/341189936>
cc `@erikdesjardins` `@JakobDegen` `@workingjubilee` `@the8472`
Fixes#106369Fixes#73258
I was looking into `array::IntoIter` optimization, and noticed that it wasn't annotating the loads with `noundef` for simple things like `array::IntoIter<i32, N>`.
Turned out to be a more general problem as `MaybeUninit::assume_init_read` isn't marking the load as initialized (<https://rust.godbolt.org/z/Mxd8TPTnv>), which is unfortunate since that's basically its reason to exist.
This PR lowers `ptr::read(p)` to `copy *p` in MIR, which fortuitiously also improves the IR we give to LLVM for things like `mem::replace`.
Querify register_tools and post-expansion early lints
The 2 extra queries correspond to code that happen before and after macro expansion, and don't need the resolver to exist.
