resolve: Cleanups and micro-optimizations to extern prelude
This is what can be done without changing the structure of `ExternPreludeEntry`, like in https://github.com/rust-lang/rust/pull/144737.
See individual commits for details.
Detect more `cfg`d out items in resolution errors
Use a visitor to collect *all* items (including those nested) that were stripped behind a `cfg` condition.
```
error[E0425]: cannot find function `f` in this scope
--> $DIR/nested-cfg-attrs.rs:4:13
|
LL | fn main() { f() }
| ^ not found in this scope
|
note: found an item that was configured out
--> $DIR/nested-cfg-attrs.rs:2:4
|
LL | fn f() {}
| ^
note: the item is gated here
--> $DIR/nested-cfg-attrs.rs:1:35
|
LL | #[cfg_attr(all(), cfg_attr(all(), cfg(FALSE)))]
| ^^^^^^^^^^
```
```
error[E0433]: failed to resolve: could not find `doesnt_exist` in `inner`
--> $DIR/diagnostics-cross-crate.rs:18:23
|
LL | cfged_out::inner::doesnt_exist::hello();
| ^^^^^^^^^^^^ could not find `doesnt_exist` in `inner`
|
note: found an item that was configured out
--> $DIR/auxiliary/cfged_out.rs:6:13
|
LL | #[cfg(false)]
| ----- the item is gated here
LL | pub mod doesnt_exist {
| ^^^^^^^^^^^^
```
Use a visitor to collect *all* items (including those nested) that were stripped behind a `cfg` condition.
```
error[E0425]: cannot find function `f` in this scope
--> $DIR/nested-cfg-attrs.rs:4:13
|
LL | fn main() { f() }
| ^ not found in this scope
|
note: found an item that was configured out
--> $DIR/nested-cfg-attrs.rs:2:4
|
LL | fn f() {}
| ^
note: the item is gated here
--> $DIR/nested-cfg-attrs.rs:1:35
|
LL | #[cfg_attr(all(), cfg_attr(all(), cfg(FALSE)))]
| ^^^^^^^^^^
```
There are many places that join path segments with `::` to produce a
string. A lot of these use `join("::")`. Many in rustdoc use
`join_with_double_colon`, and a few use `.joined("..")`. One in Clippy
uses `itertools::join`. A couple of them look for `kw::PathRoot` in the
first segment, which can be important.
This commit introduces `rustc_ast::join_path_{syms,ident}` to do the
joining for everyone. `rustc_ast` is as good a location for these as
any, being the earliest-running of the several crates with a `Path`
type. Two functions are needed because `Ident` printing is more complex
than simple `Symbol` printing.
The commit also removes `join_with_double_colon`, and
`estimate_item_path_byte_length` with it.
There are still a handful of places that join strings with "::" that are
unchanged. They are not that important: some of them are in tests, and
some of them first split a path around "::" and then rejoin with "::".
This fixes one test case where `{{root}}` shows up in an error message.
suggest declaring modules when file found but module not defined
suggests declaring modules when a module is found but not defined, i.e
```
├── main.rs: `use thing::thang;`
└── thing.rs: `struct thang`
```
or
```
├── main.rs: `use thing::thang;`
└── thing
└── mod.rs: `struct thang`
```
which currently is just
```rust
error[E0432]: unresolved import `yeah`
--> src/main.rs:1:1
|
1 | use thing::thang;
| ^^^^^ use of unresolved module or unlinked crate `thing`
|
```
but now would have this nice help:
```text
= help: you may have forgotten to declare the module `thing`. use `mod thing` in this file to declare this module.
```
```
error: cannot find attribute `empty_helper` in this scope
--> $DIR/derive-helper-legacy-limits.rs:17:3
|
LL | #[empty_helper]
| ^^^^^^^^^^^^
|
help: `empty_helper` is an attribute that can be used by the derive macro `Empty`, you might be missing a `derive` attribute
|
LL + #[derive(Empty)]
LL | struct S2;
|
```
Look at proc-macro attributes when encountering unknown attribute
```
error: cannot find attribute `sede` in this scope
--> src/main.rs:18:7
|
18 | #[sede(untagged)]
| ^^^^
|
help: the derive macros `Serialize` and `Deserialize` accept the similarly named `serde` attribute
|
18 | #[serde(untagged)]
| ~~~~~
error: cannot find attribute `serde` in this scope
--> src/main.rs:12:7
|
12 | #[serde(untagged)]
| ^^^^^
|
= note: `serde` is in scope, but it is a crate, not an attribute
help: `serde` is an attribute that can be used by the derive macros `Serialize` and `Deserialize`, you might be missing a `derive` attribute
|
10 | #[derive(Serialize, Deserialize)]
|
```
It bugs me when variables of type `Ident` are called `name`. It leads to
silly things like `name.name`. `Ident` variables should be called
`ident`, and `name` should be used for variables of type `Symbol`.
This commit improves things by by doing `s/name/ident/` on a bunch of
`Ident` variables. Not all of them, but a decent chunk.
Note potential but private items in show_candidates
Closes#138626 .
We should add potential private items to give ample hints.
And for the other seemingly false positive ` pub use crate:1️⃣:Foo;` should be kept because we don't know if the user wants to import other module's items or not, and therefore should be given the full option to do so.
r? compiler
`ast::Item` has an `ident` field.
- It's always non-empty for these item kinds: `ExternCrate`, `Static`,
`Const`, `Fn`, `Mod`, `TyAlias`, `Enum`, `Struct`, `Union`,
`Trait`, `TraitAlias`, `MacroDef`, `Delegation`.
- It's always empty for these item kinds: `Use`, `ForeignMod`,
`GlobalAsm`, `Impl`, `MacCall`, `DelegationMac`.
There is a similar story for `AssocItemKind` and `ForeignItemKind`.
Some sites that handle items check for an empty ident, some don't. This
is a very C-like way of doing things, but this is Rust, we have sum
types, we can do this properly and never forget to check for the
exceptional case and never YOLO possibly empty identifiers (or possibly
dummy spans) around and hope that things will work out.
The commit is large but it's mostly obvious plumbing work. Some notable
things.
- `ast::Item` got 8 bytes bigger. This could be avoided by boxing the
fields within some of the `ast::ItemKind` variants (specifically:
`Struct`, `Union`, `Enum`). I might do that in a follow-up; this
commit is big enough already.
- For the visitors: `FnKind` no longer needs an `ident` field because
the `Fn` within how has one.
- In the parser, the `ItemInfo` typedef is no longer needed. It was used
in various places to return an `Ident` alongside an `ItemKind`, but
now the `Ident` (if present) is within the `ItemKind`.
- In a few places I renamed identifier variables called `name` (or
`foo_name`) as `ident` (or `foo_ident`), to better match the type, and
because `name` is normally used for `Symbol`s. It's confusing to see
something like `foo_name.name`.
This way, `None` represents "crate root without a name" instead of
`kw::Empty`. This changes makes it impossible to forget to handle the
exceptional case.
The idea is to identify cases of symbols/identifiers that are not
expected to be used. There isn't a perfectly sharp line between "dummy"
and "not dummy", but I think it's useful nonetheless.
