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Auto merge of #131045 - compiler-errors:remove-unnamed_fields, r=wesleywiser

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Retire the `unnamed_fields` feature for now

`#![feature(unnamed_fields)]` was implemented in part in #115131 and #115367, however work on that feature has (afaict) stalled and in the mean time there have been some concerns raised (e.g.[^1][^2]) about whether `unnamed_fields` is worthwhile to have in the language, especially in its current desugaring. Because it represents a compiler implementation burden including a new kind of anonymous ADT and additional complication to field selection, and is quite prone to bugs today, I'm choosing to remove the feature.

However, since I'm not one to really write a bunch of words, I'm specifically *not* going to de-RFC this feature. This PR essentially *rolls back* the state of this feature to "RFC accepted but not yet implemented"; however if anyone wants to formally unapprove the RFC from the t-lang side, then please be my guest. I'm just not totally willing to summarize the various language-facing reasons for why this feature is or is not worthwhile, since I'm coming from the compiler side mostly.

Fixes #117942
Fixes #121161
Fixes #121263
Fixes #121299
Fixes #121722
Fixes #121799
Fixes #126969
Fixes #131041

Tracking:
* https://github.com/rust-lang/rust/issues/49804

[^1]: https://rust-lang.zulipchat.com/#narrow/stream/213817-t-lang/topic/Unnamed.20struct.2Funion.20fields
[^2]: https://github.com/rust-lang/rust/issues/49804#issuecomment-1972619108
This commit is contained in:
bors 2024-10-11 13:11:13 +00:00
commit f4966590d8
66 changed files with 32 additions and 3708 deletions
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23
compiler/rustc_resolve/src/build_reduced_graph.rs
View file

@ -724,29 +724,6 @@ impl<'a, 'ra, 'tcx> BuildReducedGraphVisitor<'a, 'ra, 'tcx> {
// Record field names for error reporting.
self.insert_field_idents(def_id, fields);
self.insert_field_visibilities_local(def_id.to_def_id(), fields);
for field in fields {
match &field.ty.kind {
ast::TyKind::AnonStruct(id, nested_fields)
| ast::TyKind::AnonUnion(id, nested_fields) => {
let feed = self.r.feed(*id);
let local_def_id = feed.key();
let def_id = local_def_id.to_def_id();
let def_kind = self.r.tcx.def_kind(local_def_id);
let res = Res::Def(def_kind, def_id);
self.build_reduced_graph_for_struct_variant(
&nested_fields,
Ident::empty(),
feed,
res,
// Anonymous adts inherit visibility from their parent adts.
adt_vis,
field.ty.span,
);
}
_ => {}
}
}
}
/// Constructs the reduced graph for one item.

18
compiler/rustc_resolve/src/def_collector.rs
View file

@ -105,22 +105,6 @@ impl<'a, 'ra, 'tcx> DefCollector<'a, 'ra, 'tcx> {
let name = field.ident.map_or_else(|| sym::integer(index(self)), |ident| ident.name);
let def = self.create_def(field.id, name, DefKind::Field, field.span);
self.with_parent(def, |this| visit::walk_field_def(this, field));
self.visit_anon_adt(&field.ty);
}
}
fn visit_anon_adt(&mut self, ty: &'a Ty) {
let def_kind = match &ty.kind {
TyKind::AnonStruct(..) => DefKind::Struct,
TyKind::AnonUnion(..) => DefKind::Union,
_ => return,
};
match &ty.kind {
TyKind::AnonStruct(node_id, _) | TyKind::AnonUnion(node_id, _) => {
let def_id = self.create_def(*node_id, kw::Empty, def_kind, ty.span);
self.with_parent(def_id, |this| visit::walk_ty(this, ty));
}
_ => {}
}
}
@ -476,8 +460,6 @@ impl<'a, 'ra, 'tcx> visit::Visitor<'a> for DefCollector<'a, 'ra, 'tcx> {
fn visit_ty(&mut self, ty: &'a Ty) {
match &ty.kind {
TyKind::MacCall(..) => self.visit_macro_invoc(ty.id),
// Anonymous structs or unions are visited later after defined.
TyKind::AnonStruct(..) | TyKind::AnonUnion(..) => {}
TyKind::ImplTrait(id, _) => {
// HACK: pprust breaks strings with newlines when the type
// gets too long. We don't want these to show up in compiler