Feature gating *declarations* => new crate `rustc_feature`
This PR moves the data-oriented parts of feature gating into its own crate, `rustc_feature`.
The parts consist of some data types as well as `accepted`, `active`, `removed`, and `builtin_attrs`.
Feature gate checking itself remains in `syntax::feature_gate::check`. The parts which define how to emit feature gate errors could probably be moved to `rustc_errors` or to the new `rustc_session` crate introduced in #66878. The visitor itself could probably be moved as a pass in `rustc_passes` depending on how the dependency edges work out.
The PR also contains some drive-by cleanup of feature gate checking. As such, the PR probably best read commit-by-commit.
r? @oli-obk
cc @petrochenkov
cc @Mark-Simulacrum
Rework raw ident suggestions
Use heuristics to determine whethersuggesting raw identifiers is
appropriate.
Account for raw identifiers when printing a path in a `use` suggestion.
Fix#66126.
Generic arg disambiguation
Using the tactic suggested by @petrochenkov in https://github.com/rust-lang/rust/issues/60804#issuecomment-516769465 and on [zulip](https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler/topic/generic.20argument.20disambiguation), this change checks type arguments to see if they are really incorrectly-parsed const arguments.
it should be noted that `segments.len() == 1 && segments[0].arg.is_none()` was reduced to `segments.len() == 1` as suggested by @petrochenkov in [zulip](https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler/topic/generic.20argument.20disambiguation/near/177848002). This change allowed a few more existing tests to have their braces removed.
There are a couple of "problems" with these changes that I should note. First, there was a regression in the error messages found in "src/test/ui/privacy-ns1.rs" and "src/test/ui/privacy-ns1.rs". Second, some braces were unable to be removed from "src/test/ui/const-generics/fn-const-param-infer.rs". Those on line 24 caused the statement to stop equating when removed, and those on line 20 cause a statement that should not equate to produce no error when removed.
I have not looked further into any of these issues yet, though I would be willing to look into them before landing this. I simply wanted to get some other eyes on this before going further.
Fixes#60804
cc @varkor @jplatte
A path type argument could be a generic const argument due to
limitations as to what we can determine at parsing. We double check just
to be sure by trying to resolve in the type namespace first, and if that
fails we try again in the value namespace. If resolution in the value
namespace succeeds, we have a generic const argument on our hands.
rustc_plugin: Remove `Registry::register_attribute`
Legacy plugins cannot register inert attributes anymore.
The preferred replacement is to use `register_tool` ([tracking issue](https://github.com/rust-lang/rust/issues/66079)).
```rust
#![register_tool(servo)]
#[servo::must_root]
struct S;
```
The more direct replacement is `register_attribute` ([tracking issue](https://github.com/rust-lang/rust/issues/66080))
```rust
#![register_attr(must_root)]
#[must_root]
struct S;
```
, but it requires registering each attribute individually rather than registering the tool once, and is more likely to be removed rather than stabilized.
These helpers are resolved before their respective derives through a kind of look ahead into future expansions.
Some of these will migrate to proper resolution, others will be deprecated.
```
#[trait_helper] // Deprecate
#[derive(Trait)]
#[trait_helper] // Migrate to proper resolution
```
Push `ast::{ItemKind, ImplItemKind}::OpaqueTy` hack down into lowering
We currently have a hack in the form of `ast::{ItemKind, ImplItemKind}::OpaqueTy` which is constructed literally when you write `type Alias = impl Trait;` but not e.g. `type Alias = Vec<impl Trait>;`. Per https://github.com/rust-lang/rfcs/pull/2515, this needs to change to allow `impl Trait` in nested positions. This PR achieves this change for the syntactic aspect but not the semantic one, which will require changes in lowering and def collection. In the interim, `TyKind::opaque_top_hack` is introduced to avoid knock-on changes in lowering, collection, and resolve. These hacks can then be removed and fixed one by one until the desired semantics are supported.
r? @varkor
Support registering inert attributes and attribute tools using crate-level attributes
And remove `#[feature(custom_attribute)]`.
(`rustc_plugin::Registry::register_attribute` is not removed yet, I'll do it in a follow up PR.)
```rust
#![register_attr(my_attr)]
#![register_tool(my_tool)]
#[my_attr] // OK
#[my_tool::anything] // OK
fn main() {}
```
---
Some tools (`rustfmt` and `clippy`) used in tool attributes are hardcoded in the compiler.
We need some way to introduce them without hardcoding as well.
This PR introduces a way to do it with a crate level attribute.
The previous attempt to introduce them through command line (https://github.com/rust-lang/rust/pull/57921) met some resistance.
This probably needs to go through an RFC before stabilization.
However, I'd prefer to land *this* PR without an RFC to able to remove `#[feature(custom_attribute)]` and `Registry::register_attribute` while also providing a replacement.
---
`register_attr` is a direct replacement for `#![feature(custom_attribute)]` (https://github.com/rust-lang/rust/issues/29642), except it doesn't rely on implicit fallback from unresolved attributes to custom attributes (which was always hacky and is the primary reason for the removal of `custom_attribute`) and requires registering the attribute explicitly.
It's not clear whether it should go through stabilization or not.
It's quite possible that all the uses should migrate to `#![register_tool]` (https://github.com/rust-lang/rust/issues/66079) instead.
---
Details:
- The naming is `register_attr`/`register_tool` rather than some `register_attributes` (plural, no abbreviation) for consistency with already existing attributes like `cfg_attr`, or `feature`, etc.
---
Previous attempt: https://github.com/rust-lang/rust/pull/57921
cc https://github.com/rust-lang/rust/issues/44690
Tracking issues: #66079 (`register_tool`), #66080 (`register_attr`)
Closes https://github.com/rust-lang/rust/issues/29642
This function was only ever called with 1 so there's little point in it;
this isn't an expensive operation (essentially a checked add) so we're
not really "reserving" anything either.
`MethodSig` -> `FnSig` & Use it in `ItemKind::Fn`
In both AST & HIR, rename `MethodSig` to `FnSig` and then proceed to use it in `ItemKind::Fn` so that the overall structure is more regular.
r? @davidtwco
`AttrKind` is a new type with two variants, `Normal` and `DocComment`. It's a
big performance win (over 10% in some cases) because `DocComment` lets doc
comments (which are common) be represented very cheaply.
`Attribute` gets some new helper methods to ease the transition:
- `has_name()`: check if the attribute name matches a single `Symbol`; for
`DocComment` variants it succeeds if the symbol is `sym::doc`.
- `is_doc_comment()`: check if it has a `DocComment` kind.
- `{get,unwrap}_normal_item()`: extract the item from a `Normal` variant;
panic otherwise.
Fixes#60935.
Rename `LocalInternedString` and more
This PR renames `LocalInternedString` as `SymbolStr`, removes an unnecessary `impl` from it, improves comments, and cleans up some `SymbolStr` uses.
r? @estebank
resolve: Turn the "non-empty glob must import something" error into a lint
This fixes#62334 by changing the error to a lint warning the glob. I changed the test but I'm very unsure of what I did as I do not know how to correctly check for the warning
Lint ignored `#[inline]` on function prototypes
Fixes https://github.com/rust-lang/rust/issues/51280.
- Adds a `unused_attribute` lint for `#[inline]` on function prototypes.
- As a consequence, foreign items, impl items and trait items now have their attributes checked, which could cause some code to no longer compile (it was previously erroneously ignored).
Point at the span for the definition of ADTs internal to the current
crate.
Look at the leading char of the ident to determine whether we're
expecting a likely fn or any of a fn, a tuple struct or a tuple variant.
Turn fn `add_typo_suggestion` into a `Resolver` method.
Remove `InternedString`
This PR removes `InternedString` by converting all occurrences to `Symbol`. There are a handful of places that need to use the symbol chars instead of the symbol index, e.g. for stable sorting; local conversions `LocalInternedString` is used in those places.
r? @eddyb
Correctly note code as Ok not error for E0573
Hi, this is my first pull request to the Rust project.
The fix is very small one just to fix an oversight in a comment.
Namely, [this documentation PR](https://github.com/rust-lang/rust/pull/65234) added a longer explanation for E0573. It illustrated the error using erroneous/corrected contrasting examples. But it accidentally forgot to remove `// error` from the corrected example.
Sadly, I found the error after the PR got merged. [As suggested by the original author](https://github.com/rust-lang/rust/pull/65234/files#r336518549) of the PR, I created an PR to fix this.
Part of #61137.
It's a full conversion, except in `DefKey::compute_stable_hash()` where
a `Symbol` now is converted to an `InternedString` before being hashed.
This was necessary to avoid test failures.
expand: Simplify expansion of derives
And make it more uniform with other macros.
This is done by merging placeholders for future derives' outputs into the derive container's output fragment early (addressing FIXMEs from https://github.com/rust-lang/rust/pull/63667).
Also, macros with names starting with `_` are no longer reported as unused, in accordance with the usual behavior of `unused` lints.
r? @matthewjasper or @mark-i-m
Remove last uses of gensyms
Underscore bindings now use unique `SyntaxContext`s to avoid collisions. This was the last use of gensyms in the compiler, so this PR also removes them.
closes#49300
cc #60869
r? @petrochenkov
Remove implicit dependencies on syntax::pprust
Part of https://github.com/rust-lang/rust/pull/65324.
The main goal here is to facilitate the eventual move of pprust out from libsyntax and because an AST definition typically should not depend on its pretty printer.
r? @estebank
resolve: fix error title regarding private constructors
One reason is that constructors can be private while their types can be
public.
Idea credit to @petrochenkov, discussed at #65153
Instead just use `pprust::path_to_string(..)` where needed.
This has two benefits:
a) The AST definition is now independent of printing it.
(Therefore we get closer to extracting a data-crate.)
b) Debugging should be easier as program flow is clearer.
Improve message when attempting to instantiate tuple structs with private fields
Fixes#58017, fixes#39703.
```
error[E0603]: tuple struct `Error` is private
--> main.rs:22:16
|
2 | pub struct Error(usize, pub usize, usize);
| ----- ----- field is private
| |
| field is private
...
22 | let x = a::Error(3, 1, 2);
| ^^^^^
|
= note: a tuple struct constructor is private if any of its fields is private
```
typeck: prohibit foreign statics w/ generics
Fixes#65035 and fixes#65025.
This PR modifies resolve to disallow foreign statics that have
generics.
`improper_ctypes` is not written to support type parameters, as these
are normally disallowed before the lint is run. Thus, type parameters in
foreign statics must be prohibited before the lint.
The only other case where this *could* have occured is in functions,
but typeck prohibits this with a "foreign items may not have type
parameters" error - a similar error did not exist for statics, because
statics cannot have type parameters, but they can use any
type parameters that are in scope (which isn't the case for functions).
This commit modifies resolve to disallow foreign statics that use
parent generics.
`improper_ctypes` is not written to support type parameters, as these
are normally disallowed before the lint is run. Thus, type parameters in
foreign statics must be prohibited before the lint.
The only other case where this *could* have occured is in functions,
but typeck prohibits this with a "foreign items may not have type
parameters" error - a similar error did not exist for statics, because
statics cannot have type parameters, but they can use any
type parameters that are in scope (which isn't the case for functions).
Signed-off-by: David Wood <david@davidtw.co>
Make re-export collection deterministic
Fixes https://github.com/rust-lang/rust/issues/65036
Previously, we were using an `FxHashMap` to collect module re-exports.
However, re-exports end up getting serialized into crate metadata, which
means that metadata generation was non-deterministic. This resulted in
spurious error messages changes (e.g. PR #64906) due to pretty-printing
implicitly depending on the order of re-exports when computing the
proper path to show to the user.
See #65042 for a long-term strategy to detect this kind of issue
Stabilize `Option::as_deref` and `Option::as_deref_mut`
The tracking issue https://github.com/rust-lang/rust/issues/50264 still has unresolved question for the corresponding `Result` methods.
Previously, we were using an `FxHashMap` to collect module re-exports.
However, re-exports end up getting serialized into crate metadata, which
means that metadata generation was non-deterministic. This resulted in
spurious error messages changes (e.g. PR #64906) due to pretty-printing
implicitly depending on the order of re-exports when computing the
proper path to show to the user.
See #65042 for a long-term strategy to detect this kind of issue
(Without this commit, you still get an error (a very similar one, at
that), but it complains about use of forward declaration, which is
confusing since people do not necessarily think of `Self` as being
declared at all.)
Update: incorporate review feedback.
Cleanup handling of hygiene for built-in macros
This makes most identifiers generated by built-in macros use def-site hygiene, not only the ones that previously used gensyms.
* `ExtCtxt::ident_of` now takes a `Span` and is preferred to `Ident::{from_str, from_str_and_span}`
* Remove `Span::with_legacy_ctxt`
* `assert` now uses call-site hygiene because it needs to resolve `panic` unhygienically.
* `concat_idents` now uses call-site hygiene because it wouldn't be very useful with def-site hygiene.
* everything else is moved to def-site hygiene
r? @petrochenkov
resolve: Do not afraid to set current module to enums and traits
After cfbb60bf6d it's ok.
This is likely required for https://github.com/rust-lang/rust/pull/63468 to work correctly, because that PR starts resolving attributes on enum variants.
r? @matthewjasper @c410-f3r
Use hygiene for AST passes
AST passes are now able to have resolve consider their expansions as if they were opaque macros defined either in some module in the current crate, or a fake empty module with `#[no_implicit_prelude]`.
* Add an ExpnKind for AST passes.
* Remove gensyms in AST passes.
* Remove gensyms in`#[test]`, `#[bench]` and `#[test_case]`.
* Allow opaque macros to define tests.
* Move tests for unit tests to their own directory.
* Remove `Ident::{gensym, is_gensymed}` - `Ident::gensym_if_underscore` still exists.
cc #60869, #61019
r? @petrochenkov
resolve: Block expansion of a derive container until all its derives are resolved
So, it turns out there's one more reason to block expansion of a `#[derive]` container until all the derives inside it are resolved, beside `Copy` (https://github.com/rust-lang/rust/pull/63248).
The set of derive helper attributes registered by derives in the container also has to be known before the derives themselves are expanded, otherwise it may be too late (see https://github.com/rust-lang/rust/pull/63468#issuecomment-524550872 and the `#[stable_hasher]`-related test failures in https://github.com/rust-lang/rust/pull/63468).
So, we stop our attempts to unblock the container earlier, as soon as the `Copy` status is known, and just block until all its derives are resolved.
After all the derives are resolved we immediately go and process their helper attributes in the item, without delaying it until expansion of the individual derives.
Unblocks https://github.com/rust-lang/rust/pull/63468
r? @matthewjasper (as a reviewer of https://github.com/rust-lang/rust/pull/63248)
cc @c410-f3r
Also mark derive helpers as known as a part of the derive container's expansion instead of expansion of the derives themselves which may happen too late.
