Store idents for `DefPathData` into crate metadata
Previously, we threw away the `Span` associated with a definition's
identifier when we encoded crate metadata, causing us to lose location
and hygiene information.
We now store the identifier's `Span` in a side table, which gets encoded
into the crate metadata. When we decode items from the metadata, we
combine the name and span back into an `Ident`.
This improves the output of several tests, which previously had messages
suppressed due to dummy spans.
This is a prerequisite for #68686, since throwing away a `Span` means
that we lose hygiene information.
Increase verbosity when suggesting subtle code changes
Do not suggest changes that are actually quite small inline, to minimize the likelihood of confusion.
Fix#69243.
Previously, we threw away the `Span` associated with a definition's
identifier when we encoded crate metadata, causing us to lose location
and hygiene information.
We now store the identifier's `Span` in the crate metadata.
When we decode items from the metadata, we combine
the name and span back into an `Ident`.
This improves the output of several tests, which previously had messages
suppressed due to dummy spans.
This is a prerequisite for #68686, since throwing away a `Span` means
that we lose hygiene information.
resolve: Avoid "self-confirming" import resolutions in one more case
So the idea behind "blacklisted bindings" is that we must ignore some name definitions during resolution because otherwise they cause infinite cycles.
E.g. import
```rust
use my_crate;
```
would refer to itself (on 2018 edition) without this blacklisting, because `use my_crate;` is the first name in scope when we are resolving `my_crate` here.
In this PR we are doing this blacklisting for the case
```rust
use same::same;
```
, namely blacklisting the second `same` when resolving the first `same`.
This was previously forgotten.
Fixes https://github.com/rust-lang/rust/issues/62767
Liberate `rustc_ast_lowering` from `rustc`
The whole point of this PR is the very last commit, in which we remove `rustc` as one of `rustc_ast_lowering`'s dependencies, thereby improving `./x.py` parallelism and working towards https://github.com/rust-lang/rust/issues/65031.
Noteworthy:
- From `rustc::arena` we move logic into `arena`, in particular `declare_arena!`. This is then used in `rustc_ast_lowering` so that lowering has its own separate arena.
- Some linting code is unfortunately moved to `rustc_session::lint` cause its used both in `rustc_lint` and `rustc_ast_lowering`, and this is their common dependency.
- `rustc_session::CrateDisambiguator` is moved into `rustc_ast` so that `rustc::hir::map::definitions` can be moved into `rustc_hir`, so that `rustc_ast_lowering` can stop referring to `rustc::hir`.
r? @Zoxc
couple more clippy fixes (let_and_return, if_same_then_else)
* summarize if-else-code with identical blocks (clippy::if_same_then_else)
* don't create variable bindings just to return the bound value immediately (clippy::let_and_return)
Remove some imports to the rustc crate
- When we have `NestedVisitorMap::None`, we use `type Map = dyn intravisit::Map<'v>;` instead of the actual map. This doesn't actually result in dynamic dispatch (in the future we may want to use an associated type default to simplify the code).
- Use `rustc_session::` imports instead of `rustc::{session, lint}`.
r? @Zoxc
expand: Implement something similar to `#[cfg(accessible(path))]`
cc https://github.com/rust-lang/rust/issues/64797
The feature is implemented as a `#[cfg_accessible(path)]` attribute macro rather than as `#[cfg(accessible(path))]` because it needs to wait until `path` becomes resolvable, and `cfg` cannot wait, but macros can wait.
Later we can think about desugaring or not desugaring `#[cfg(accessible(path))]` into `#[cfg_accessible(path)]`.
This implementation is also incomplete in the sense that it never returns "false" from `cfg_accessible(path)`, it requires some tweaks to resolve, which is not quite ready to answer queries like this during early resolution.
However, the most important part of this PR is not `cfg_accessible` itself, but expansion infrastructure for retrying expansions.
Before this PR we could say "we cannot resolve this macro path, let's try it later", with this PR we can say "we cannot expand this macro, let's try it later" as well.
This is a pre-requisite for
- turning `#[derive(...)]` into a regular attribute macro,
- properly supporting eager expansion for macros that cannot yet be resolved like
```
fn main() {
println!(not_available_yet!());
}
macro_rules! make_available {
() => { #[macro_export] macro_rules! not_available_yet { () => { "Hello world!" } }}
}
make_available!();
```
resolve/hygiene: `macro_rules` are not "legacy"
The "modern" vs "legacy" naming was introduced by jseyfried during initial implementation of macros 2.0.
At this point it's clear that `macro_rules` are not going anywhere and won't be deprecated in the near future.
So this PR changes the naming "legacy" (when it implies "macro_rules") to "macro_rules".
This should also help people reading this code because it's wasn't obvious that "legacy" actually meant "macro_rules" in these contexts.
The most contentious renaming here is probably
```
fn modern -> fn normalize_to_macros_2_0
fn modern_and_legacy -> fn normalize_to_macro_rules
```
Other alternatives that I could think of are `normalize_to_opaque`/`normalize_to_semitransparent`, or `strip_non_opaque`/`strip_transparent`, but they seemed less intuitive.
The documentation to these functions can be found in `symbol.rs`.
r? @matthewjasper
def_collector: Fully visit async functions
We forgot to visit attributes previously, it caused ICEs.
Special treatment of async functions is also moved from `visit_item` to `visit_fn` to reuse more of the default visitor.
Fixes https://github.com/rust-lang/rust/issues/67778.
ast: `Mac`/`Macro` -> `MacCall`
It's now obvious that these refer to macro calls rather than to macro definitions.
It's also a single name instead of two different names in different places.
`rustc_expand` usually calls macro calls in a wide sense (including attributes and derives) "macro invocations", but structures and variants renamed in this PR are only relevant to fn-like macros, so it's simpler and clearer to just call them calls.
cc https://github.com/rust-lang/rust/pull/63586#discussion_r314232513
r? @eddyb
