Fix anon const def-creation when macros are involved
Fixes#128016.
Ever since #125915, some `ast::AnonConst`s turn into `hir::ConstArgKind::Path`s,
which don't have associated `DefId`s. To deal with the fact that we don't have
resolution information in `DefCollector`, we decided to implement a process
where if the anon const *appeared* to be trivial (i.e., `N` or `{ N }`), we
would avoid creating a def for it in `DefCollector`. If later, in AST lowering,
we realized it turned out to be a unit struct literal, or we were lowering it
to something that didn't use `hir::ConstArg`, we'd create its def there.
However, let's say we have a macro `m!()` that expands to a reference to a free
constant `FOO`. If we use `m!()` in the body of an anon const (e.g., `Foo<{ m!() }>`),
then in def collection, it appears to be a nontrivial anon const and we create
a def. But the macro expands to something that looks like a trivial const arg,
but is not, so in AST lowering we "fix" the mistake we assumed def collection
made and create a def for it. This causes a duplicate definition ICE.
The long-term fix for this is to delay the creation of defs for all expression-like
nodes until AST lowering (see #128844 for an incomplete attempt at this). This
would avoid issues like this one that are caused by hacky workarounds. However,
doing this uncovers a pre-existing bug with opaque types that is quite involved
to fix (see #129023).
In the meantime, this PR fixes the bug by delaying def creation for anon consts
whose bodies are macro invocations until after we expand the macro and know
what is inside it. This is accomplished by adding information to create the
anon const's def to the data in `Resolver.invocation_parents`.
r? `@BoxyUwU`
Ever since #125915, some `ast::AnonConst`s turn into `hir::ConstArgKind::Path`s,
which don't have associated `DefId`s. To deal with the fact that we don't have
resolution information in `DefCollector`, we decided to implement a process
where if the anon const *appeared* to be trivial (i.e., `N` or `{ N }`), we
would avoid creating a def for it in `DefCollector`. If later, in AST lowering,
we realized it turned out to be a unit struct literal, or we were lowering it
to something that didn't use `hir::ConstArg`, we'd create its def there.
However, let's say we have a macro `m!()` that expands to a reference to a free
constant `FOO`. If we use `m!()` in the body of an anon const (e.g., `Foo<{ m!() }>`),
then in def collection, it appears to be a nontrivial anon const and we create
a def. But the macro expands to something that looks like a trivial const arg,
but is not, so in AST lowering we "fix" the mistake we assumed def collection
made and create a def for it. This causes a duplicate definition ICE.
The ideal long-term fix for this is a bit unclear. One option is to delay def
creation for all expression-like nodes until AST lowering (see #128844 for an
incomplete attempt at this). This would avoid issues like this one that are
caused by hacky workarounds. However, this approach has some downsides as well,
and the best approach is yet to be determined.
In the meantime, this PR fixes the bug by delaying def creation for anon consts
whose bodies are macro invocations until after we expand the macro and know
what is inside it. This is accomplished by adding information to create the
anon const's def to the data in `Resolver.invocation_parents`.
`rustc_resolve` allocates many things in `ResolverArenas`. The lifetime
used for references into the arena is mostly `'a`, and sometimes `'b`.
This commit changes it to `'ra`, which is much more descriptive. The
commit also changes the order of lifetimes on a couple of structs so
that '`ra` is second last, before `'tcx`, and does other minor
renamings such as `'r` to `'a`.
Add `REDUNDANT_IMPORTS` lint for new redundant import detection
Defaults to Allow for now. Stacked on #123744 to avoid merge conflict, but much easier to review all as one.
r? petrochenkov
When encountering a name in an import that could have come from a crate that wasn't imported, use a structured suggestion to suggest `extern crate foo;` pointing at the right place in the crate.
When encountering `_` in an import, do not suggest `extern crate _;`.
```
error[E0432]: unresolved import `spam`
--> $DIR/import-from-missing-star-3.rs:2:9
|
LL | use spam::*;
| ^^^^ maybe a missing crate `spam`?
|
help: consider importing the `spam` crate
|
LL + extern crate spam;
|
```
Use field ident spans directly instead of the full field span in diagnostics on local fields
This improves diagnostics and avoids having to store the `DefId`s of fields
Silence some resolve errors when there have been glob import errors
When encountering `use foo::*;` where `foo` fails to be found, and we later encounter resolution errors, we silence those later errors.
A single case of the above, for an *existing* import on a big codebase would otherwise have a huge number of knock-down spurious errors.
Ideally, instead of a global flag to silence all subsequent resolve errors, we'd want to introduce an unnameable binding in the appropriate rib as a sentinel when there's a failed glob import, so when we encounter a resolve error we can search for that sentinel and if found, and only then, silence that error. The current approach is just a quick proof of concept to iterate over.
Partially address #96799.
When encountering `use foo::*;` where `foo` fails to be found, and we later
encounter resolution errors, we silence those later errors.
A single case of the above, for an *existing* import on a big codebase would
otherwise have a huge number of knock-down spurious errors.
Ideally, instead of a global flag to silence all subsequent resolve errors,
we'd want to introduce an unameable binding in the appropriate rib as a
sentinel when there's a failed glob import, so when we encounter a resolve
error we can search for that sentinel and if found, and only then, silence
that error. The current approach is just a quick proof of concept to
iterate over.
Partially address #96799.
Also allow `impl Trait` in delegated functions.
The delegation item will refer to the original opaque type from the callee, fresh opaque type won't be created.
Remove `feed_local_def_id`
best reviewed commit by commit
Basically I returned `TyCtxtFeed` from `create_def` and then preserved that in the local caches
based on https://github.com/rust-lang/rust/pull/121084
r? ````@petrochenkov````
fixes#117448
For example unnecessary imports in std::prelude that can be eliminated:
```rust
use std::option::Option::Some;//~ WARNING the item `Some` is imported redundantly
use std::option::Option::None; //~ WARNING the item `None` is imported redundantly
```
Invert diagnostic lints.
That is, change `diagnostic_outside_of_impl` and `untranslatable_diagnostic` from `allow` to `deny`, because more than half of the compiler has been converted to use translated diagnostics.
This commit removes more `deny` attributes than it adds `allow` attributes, which proves that this change is warranted.
r? ````@davidtwco````
resolve: Unload speculatively resolved crates before freezing cstore
Name resolution sometimes loads additional crates to improve diagnostics (e.g. suggest imports).
Not all of these diagnostics result in errors, sometimes they are just warnings, like in #117772.
If additional crates loaded speculatively stay and gets listed by things like `query crates` then they may produce further errors like duplicated lang items, because lang items from speculatively loaded crates are as good as from non-speculatively loaded crates.
They can probably do things like adding unintended impls from speculatively loaded crates to method resolution as well.
The extra crates will also get into the crate's metadata as legitimate dependencies.
In this PR I remove the speculative crates from cstore when name resolution is finished and cstore is frozen.
This is better than e.g. filtering away speculative crates in `query crates` because things like `DefId`s referring to these crates and leaking to later compilation stages can produce ICEs much easier, allowing to detect them.
The unloading could potentially be skipped if any errors were reported (to allow using `DefId`s from speculatively loaded crates for recovery), but I didn't do it in this PR because I haven't seen such cases of recovery. We can reconsider later if any relevant ICEs are reported.
Unblocks https://github.com/rust-lang/rust/pull/117772.
