rustc_span: More consistent span combination operations
Also add more tests for using `tt` in addition to `ident`, and some other minor tweaks, see individual commits.
This is a part of https://github.com/rust-lang/rust/pull/119412 that doesn't yet add side tables for metavariable spans.
rustc_span: Optimize syntax context comparisons
Including comparisons with root context.
- `eq_ctxt` doesn't require retrieving full `SpanData`, or taking the span interner lock twice.
- Checking `SyntaxContext` for "rootness" is cheaper than extracting a full outer `ExpnData` for it and checking *it* for rootness.
The internal lint for `eq_ctxt` is also tweaked to detect `a.ctxt() != b.ctxt()` in addition to `a.ctxt() == b.ctxt()`.
Avoid a `track_errors` by bubbling up most errors from `check_well_formed`
I believe `track_errors` is mostly papering over issues that a sufficiently convoluted query graph can hit. I made this change, while the actual change I want to do is to stop bailing out early on errors, and instead use this new `ErrorGuaranteed` to invoke `check_well_formed` for individual items before doing all the `typeck` logic on them.
This works towards resolving https://github.com/rust-lang/rust/issues/97477 and various other ICEs, as well as allowing us to use parallel rustc more (which is currently rather limited/bottlenecked due to the very sequential nature in which we do `rustc_hir_analysis::check_crate`)
cc `@SparrowLii` `@Zoxc` for the new `try_par_for_each_in` function
The `rustc_span::FileName` enum already differentiates between real
files and "fake" files such as `<anon>`. We do not need to artificially
forbid real file names from ending in `>`.
Fix argument removal suggestion around macros
Fixes#112437.
Fixes#113866.
Helps with #114255.
The issue was that `span.find_ancestor_inside(outer)` could previously return a span with a different expansion context from `outer`.
This happens for example for the built-in macro `panic!`, which expands to another macro call of `panic_2021!` or `panic_2015!`. Because the call site of `panic_20xx!` has not associated source code, its span currently points to the call site of `panic!` instead.
Something similar also happens items that get desugared in AST->HIR lowering. For example, `for` loops get two spans: One "inner" span that has the `.desugaring_kind()` kind set to `DesugaringKind::ForLoop` and one "outer" span that does not. Similar to the macro situation, both of these spans point to the same source code, but have different expansion contexts.
This causes problems, because joining two spans with different expansion contexts will usually[^1] not actually join them together to avoid creating "spaghetti" spans that go from the macro definition to the macro call. For example, in the following snippet `full_span` might not actually contain the `adjusted_start` and `adjusted_end`. This caused the broken suggestion / debug ICE in the linked issues.
```rust
let adjusted_start = start.find_ancestor_inside(shared_ancestor);
let adjusted_end = end.find_ancestor_inside(shared_ancestor);
let full_span = adjusted_start.to(adjusted_end)
```
To fix the issue, this PR introduces a new method, `find_ancestor_inside_same_ctxt`, which combines the functionality of `find_ancestor_inside` and `find_ancestor_in_same_ctxt`: It finds an ancestor span that is contained within the parent *and* has the same syntax context, and is therefore safe to extend. This new method should probably be used everywhere, where the returned span is extended, but for now it is just used for the argument removal suggestion.
Additionally, this PR fixes a second issue where the function call itself is inside a macro but the arguments come from outside the macro. The test is added in the first commit to include stderr diff, so this is best reviewed commit by commit.
[^1]: If one expansion context is the root context and the other is not.
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^^
Mark `ErrorGuaranteed` constructor as deprecated so people don't use it
You should never ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever use this function unless you know what you're doing, so make it harder to accidentally use it!
Alternatives are to change the name to sound scarier, make it `unsafe` (though it's not really a soundness thing), or work on deeper refactors to make it private.
r? `@BoxyUwU`
Make `impl Debug for Span` not panic on not having session globals.
I hit the panic that this patch avoids while messing with the early lints in `rustc_session::config::build_session_options()`. The rest of that project is not finished, but this seemed like a self-contained improvement.
(Should changes like this add tests? I don't see similar unit tests.)
Remove some suspicious cast truncations
These truncations were added a long time ago, and as best I can tell without a perf justification. And with rust-lang/rust#110410 it has become perf-neutral to not truncate anymore. We worked hard for all these bits, let's use them.
Rename `with_source_map` as `set_source_map`. Because `with` functions
(e.g. `with_session_globals`, `scoped_tls::ScopedKey::with`) are for
*getting* a value for the duration of a closure, and `set` functions
(e.g. `set_session_globals_then` `scoped_tls::ScopedKey::with`) are for
*setting* a value for the duration of a closure.
Also fix up the comment, which is wrong:
- The bit about `TyCtxt` is wrong.
- `span_debug1` doesn't exist any more.
- There's only one level of fallback, not two.
(This is effectively a follow-up to the changes in #93936.)
Also add a comment explaining that `SessionGlobals::source_map` should
only be used when absolutely necessary.
Convert all the crates that have had their diagnostic migration
completed (except save_analysis because that will be deleted soon and
apfloat because of the licensing problem).
Fix line numbers for MIR inlined code
`should_collapse_debuginfo` detects if the specified span is part of a
macro expansion however it does this by checking if the span is anything
other than a normal (non-expanded) kind, then the span sequence is
walked backwards to the root span.
This doesn't work when the MIR inliner inlines code as it creates spans
with expansion information set to `ExprKind::Inlined` and results in the
line number being attributed to the inline callsite rather than the
normal line number of the inlined code.
Fixes#103068
Shorten the `lookup_line` code slightly
The `match` looks like it's exactly the same as `checked_sub(1)`, so we might as well see if perf says we can just do that to save a couple lines.
`should_collapse_debuginfo` detects if the specified span is part of a
macro expansion however it does this by checking if the span is anything
other than a normal (non-expanded) kind, then the span sequence is
walked backwards to the root span.
This doesn't work when the MIR inliner inlines code as it creates spans
with expansion information set to `ExprKind::Inlined` and results in the
line number being attributed to the inline callsite rather than the
normal line number of the inlined code.
Inline SyntaxContext in both encoded span representation.
The current interned representation for spans does not use the `ctxt_or_zero: u16` field. This PR proposes to use this field to store the `SyntaxContext` of the interned span instead. When `ctxt_or_zero` and the interned span's `ctxt` don't match, the inlined one takes precedence.
This allows to implement `Span::ctxt` and `Span::with_ctxt` with much less probability to access the interner. Those functions are used a lot for hygiene, so this may be worth it.
On later stages, the feature is already stable.
Result of running:
rg -l "feature.let_else" compiler/ src/librustdoc/ library/ | xargs sed -s -i "s#\\[feature.let_else#\\[cfg_attr\\(bootstrap, feature\\(let_else\\)#"
Debuginfo line information for macro invocations are collapsed by
default - line information are replaced by the line of the outermost
expansion site. Using `-Zdebug-macros` disables this behaviour.
When the `collapse_debuginfo` feature is enabled, the default behaviour
is reversed so that debuginfo is not collapsed by default. In addition,
the `#[collapse_debuginfo]` attribute is available and can be applied to
macro definitions which will then have their line information collapsed.
Signed-off-by: David Wood <david.wood@huawei.com>
Add the diagnostic translation lints to crates that don't emit them
Some of these have a note saying that they should build on a stable compiler, does that mean they shouldn't get these lints? Or can we cfg them out on those?
