syntax: account for CVarArgs being in the argument list.
Fixes#63430 by testing for `1` argument (the `CVarArgs` itself) instead of `0`.
Note that the error has basically been impossible to trigger since the change that caused #63430, so perhaps we need an audit of untested errors.
Also, this check probably belongs in AST validation/HIR lowering, but I'd rather fix it in place for now.
r? @petrochenkov cc @dlrobertson
Each call to `fully_expand_fragment` is something unique, interesting, and requiring attention.
It represents a "root" of expansion and its use means that something unusual is happening, like eager expansion or expansion performed outside of the primary expansion pass.
So, it shouldn't be hide under a generic visitor call.
Also, from all the implemented visitor methods only two were actually used.
resolve: Remove remaining special cases from built-in macros
Edition and definition sites of the macros are now also taken from the `#[rustc_builtin_macro]` definitions in `libcore`.
---
The edition switch may be a breaking change for `Rustc{Encodable,Decodable}` derives if they are used in combination with the unstable crate `serialize` from sysroot like this
```rust
extern crate serialize;
use serialize as rustc_serialize;
#[derive(RustcEncodable)]
struct S;
```
(see the updated `ui-fulldeps` tests).
More explicit diagnostic when using a `vec![]` in a pattern
```
error: unexpected `(` after qualified path
--> $DIR/vec-macro-in-pattern.rs:3:14
|
LL | Some(vec![x]) => (),
| ^^^^^^^
| |
| unexpected `(` after qualified path
| in this macro invocation
| use a slice pattern here instead
|
= help: for more information, see https://doc.rust-lang.org/edition-guide/rust-2018/slice-patterns.html
= note: this warning originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
```
Fix#61933.
```
error: unexpected `(` after qualified path
--> $DIR/vec-macro-in-pattern.rs:3:14
|
LL | Some(vec![x]) => (),
| ^^^^^^^
| |
| unexpected `(` after qualified path
| in this macro invocation
| use a slice pattern here instead
|
= help: for more information, see https://doc.rust-lang.org/edition-guide/rust-2018/slice-patterns.html
= note: this warning originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
```
Move special treatment of `derive(Copy, PartialEq, Eq)` from expansion infrastructure to elsewhere
As described in https://github.com/rust-lang/rust/pull/62086#issuecomment-515195477.
Reminder:
- `derive(PartialEq, Eq)` makes the type it applied to a "structural match" type, so constants of this type can be used in patterns (and const generics in the future).
- `derive(Copy)` notifies other derives that the type it applied to implements `Copy`, so `derive(Clone)` can generate optimized code and other derives can generate code working with `packed` types and types with `rustc_layout_scalar_valid_range` attributes.
First, the special behavior is now enabled after properly resolving the derives, rather than after textually comparing them with `"Copy"`, `"PartialEq"` and `"Eq"` in `fn add_derived_markers`.
The markers are no longer kept as attributes in AST since derives cannot modify items and previously did it through hacks in the expansion infra.
Instead, the markers are now kept in a "global context" available from all the necessary places, namely - resolver.
For `derive(PartialEq, Eq)` the markers are created by the derive macros themselves and then consumed during HIR lowering to add the `#[structural_match]` attribute in HIR.
This is still a hack, but now it's a hack local to two specific macros rather than affecting the whole expansion infra.
Ideally we should find the way to put `#[structural_match]` on the impls rather than on the original item, and then consume it in `rustc_mir`, then no hacks in expansion and lowering will be required.
(I'll make an issue about this for someone else to solve, after this PR lands.)
The marker for `derive(Copy)` cannot be emitted by the `Copy` macro itself because we need to know it *before* the `Copy` macro is expanded for expanding other macros.
So we have to do it in resolve and block expansion of any derives in a `derive(...)` container until we know for sure whether this container has `Copy` in it or not.
Nasty stuff.
r? @eddyb or @matthewjasper
Rename `ItemKind::Ty` to `ItemKind::TyAlias`
The current name is not entirely clear without context and `TyAlias` is consistent with `ItemKind::TraitAlias`.
