Improve check-cfg diagnostics
This PR tries to improve some of the diagnostics of check-cfg.
The main changes is the unexpected name or value being added to the main diagnostic:
```diff
- warning: unexpected `cfg` condition name
+ warning: unexpected `cfg` condition name: `widnows`
```
It also cherry-pick the better sensible logic for when we print the list of expected values when we have a matching value for a very similar name.
Address https://github.com/rust-lang/rust/pull/111072#discussion_r1356818100
r? `@petrochenkov`
Streamline `rustc_driver_impl` pretty-printing.
This PR simplifies a lot of unnecessary structure in
`rustc_driver_impl/src/pretty.rs`. It removes some traits and functions,
simplifies some structs, renames some things for increased consistency, and
eliminates some boilerplate code. Overall it cuts more than 150 lines of code.
r? `@compiler-errors`
Remove cgu_reuse_tracker from Session
This removes a bit of global mutable state.
It will now miss post-lto cgu reuse when ThinLTO determines that a cgu doesn't get changed, but there weren't any tests for this anyway and a test for it would be fragile to the exact implementation of ThinLTO in LLVM.
exhaustiveness: Rework constructor splitting
`SplitWildcard` was pretty opaque. I replaced it with a more legible abstraction: `ConstructorSet` represents the set of constructors for patterns of a given type. This clarifies responsibilities: `ConstructorSet` handles one clear task, and diagnostic-related shenanigans can be done separately.
I'm quite excited, I had has this in mind for years but could never quite introduce it. This opens up possibilities, including type-specific optimisations (like using a `FxHashSet` to collect enum variants, which had been [hackily attempted some years ago](https://github.com/rust-lang/rust/pull/76918)), my one-pass rewrite (https://github.com/rust-lang/rust/pull/116042), and future librarification.
`NoAnn` and `IdentifiedAnnotation` impl both `pprust_ast::PpAnn` and
`pprust_hir::PpAnn`, which is a bit confusing, because the optional
`tcx` is only needed for the HIR cases. (Currently the `tcx` is
unnecessarily provided in the `expanded` AST cases.)
This commit splits each one into `Ast` and `Hir` versions, which makes
things clear about where the `tcx` is needed. The commit also renames
all the traits so they consistently end with `Ann`.
`call_with_pp_support_ast` and `call_with_pp_support_hir` how each have
a single call site. This commit inlines and removes them, which also
removes the need for all the supporting traits: `Sess`,
`AstPrinterSupport`, and `HirPrinterSupport`. The `sess` member is also
removed from several structs.
The handling of the `PpMode` variants is currently spread across three
functions: `print_after_parsing`, `print_after_hir_lowering`, and
`print_with_analysis`. Each one handles some of the variants. This split
is primarily because `print_after_parsing` has slightly different
arguments to the other two.
This commit changes the structure. It merges the three functions into a
single `print` function, and encapsulates the different arguments in a
new enum `PrintExtra`.
Benefits:
- The code is a little shorter.
- All the `PpMode` variants are handled in a single `match`, with no
need for `unreachable!` arms.
- It enables the trait removal in the subsequent commit by reducing
the number of `call_with_pp_support_ast` call sites from two to one.
First, both `AstPrinterSupport` and `HirPrinterSupport` have a `sess`
method. This commit introduces a `Sess` trait and makes the support
traits be subtraits of `Sess`, to avoid some duplication.
Second, both support traits have a `pp_ann` method that isn't needed if
we enable `trait_upcasting`. This commit removes those methods.
(Both of these traits will be removed in a subsequent commit, as will
the `trait_upcasting` use.)
`phase_3_run_analysis_passes` no longer exists, and AFAICT this code has
been refactored so much since this comment was written that it no longer
has any useful meaning.
Copy 1-element arrays as scalars, not vectors
For `[T; 1]` it's silly to copy as `<1 x T>` when we can just copy as `T`.
Inspired by https://github.com/rust-lang/rust/issues/101210#issuecomment-1732470941, which pointed out that `Option<[u8; 1]>` was codegenning worse than `Option<u8>`.
(I'm not sure *why* LLVM doesn't optimize out `<1 x u8>`, but might as well just not emit it in the first place in this codepath.)
---
I think I bit off too much in #116479; let me try just the scalar case first.
r? `@ghost`
Fix mips platform support entries.
The table entries for these MIPS entries were broken because they had the wrong number of columns (from #116503). Additionally, there was a conflict with #115238, which made the same change (but on different lines, so git didn't complain).
coverage: Clarify loop-edge detection and graph traversal
This is a collection of improvements to two semi-related pieces of code:
- The code in `counters` that detects which graph edges don't exit a loop, and would therefore be good candidates to have their coverage computed as an expression rather than having a physical counter.
- The code in `graph` that traverses the coverage BCB graph in a particular order, and tracks loops and loop edges along the way (which is relevant to the above).
I was originally only planning to make the `graph` changes, but there was going to be a lot of indentation churn in `counters` anyway, and once I started looking I noticed a lot of opportunities for simplification.
---
`@rustbot` label +A-code-coverage
Handle several `#[diagnostic::on_unimplemented]` attributes correctly
This PR fixes an issues where rustc would ignore subsequent `#[diagnostic::on_unimplemented]` attributes. The [corresponding RFC](https://rust-lang.github.io/rfcs/3368-diagnostic-attribute-namespace.html) specifies that the first matching instance of each option is used. Invalid attributes are linted and otherwise ignored.
Having to keep passing in a graph reference was a holdover from when the graph
was partly mutated during traversal. As of #114354 that is no longer necessary,
so we can simplify the traversal code by storing a graph reference as a field
in `TraverseCoverageGraphWithLoops`.
The previous code was storing the worklist in a vector, and then selectively
adding items to the start or end of the vector. That's a perfect use-case for a
double-ended queue.
This change also reveals that the existing code was a bit confused about which
end of the worklist is the front or back. For now, items are always removed
from the front of the queue (instead of the back), and code that adds items to
the queue has been flipped, to preserve the existing behaviour.
Show enum discriminant if a compatible repr is used
Follow-up of #116142.
It was mentioned in the [team meeting](https://rust-lang.zulipchat.com/#narrow/stream/393423-t-rustdoc.2Fmeetings/topic/meeting.2002-10-2023/near/394504024) that an enum with a `repr` should also get its discriminants displayed. Forgot to implement it in #116142...
It also allowed to uncover a bug: i was not providing the correct `DefId` in case it was a type alias to `render_enum_fields`. It's also fixed in this PR.
r? `@fmease`
Fix duplicate note on internal feature gates with associated issues
Fixes#116293
Note sure if I should add tests because the issue occurs only for feature gates having associated issues and that set of feature gates will change unpredictably leading to an unnecessary churn in tests.
Use structured suggestion for #113174
When encountering a for loop that is rejected by the borrow checker because it is being advanced within its body, provide a structured suggestion for `while let Some(pat) = iter.next()`.
The BuiltinInternalFeatures gate already has a struct level #[note]
attribute. The additional note field in it caused a duplicate to be
displayed when it was set to Some(...) which happened when the
feature had an associated issue
Remove unnecessary tmp variable in default_read_exact
This `tmp` variable has existed since the original implementation (added in ff81920f03), but it's not necessary (maybe non-lexical lifetimes helped?).
It's common to read std source code to understand how things actually work, and this tripped me up on my first read.
Pass rustc shim flags using environment variable
This PR implements a generalized way of passing of host flags to the `rustc` shim in bootstrap, as proposed [here](https://github.com/rust-lang/rust/pull/116278#discussion_r1346979960).
I tried to implement the bootstrap side using `OsString`, but then I realized that the shim code was using `env::var` before anyway, instead of `env::var_os`, so I just settled on a `String`. The shim side is still general and uses `env::vars_os` now.
I'm not sure if we actually need to do something with the `rustdoc` shim. It *seems* to me that the env. vars passed to it (`RUSTDOC_LINKER`) and (`RUSTDOC_LLD_NO_THREADS`) could just be passed to cargo directly (or rather, the commands that they invoke in the shim could be passed directly). I'm not sure why are they set by the shim.
r? `@onur-ozkan`
CC `@petrochenkov`
