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Rollup merge of #146004 - petrochenkov:epentry, r=nnethercote

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resolve: Refactor `struct ExternPreludeEntry`

Avoid impossible combinations of fields and apply the first part of https://github.com/rust-lang/rust/pull/144737 (do not resolve erroneous entries repeatedly, keep them as `PendingBinding::Ready(None)` instead).
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Stuart Cook 2025-09-01 12:42:26 +10:00 • committed by GitHub
commit 5adc0fe0e2
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4 changed files with 57 additions and 54 deletions
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9
compiler/rustc_resolve/src/build_reduced_graph.rs
View file

@ -1008,16 +1008,13 @@ impl<'a, 'ra, 'tcx> BuildReducedGraphVisitor<'a, 'ra, 'tcx> {
let msg = format!("extern crate `{ident}` already in extern prelude");
self.r.tcx.dcx().span_delayed_bug(item.span, msg);
} else {
entry.item_binding = Some(imported_binding);
entry.introduced_by_item = orig_name.is_some();
entry.item_binding = Some((imported_binding, orig_name.is_some()));
}
entry
}
Entry::Vacant(vacant) => vacant.insert(ExternPreludeEntry {
item_binding: Some(imported_binding),
flag_binding: Cell::new(None),
only_item: true,
introduced_by_item: true,
item_binding: Some((imported_binding, true)),
flag_binding: None,
}),
};
}

2
compiler/rustc_resolve/src/check_unused.rs
View file

@ -204,7 +204,7 @@ impl<'a, 'ra, 'tcx> UnusedImportCheckVisitor<'a, 'ra, 'tcx> {
.r
.extern_prelude
.get(&Macros20NormalizedIdent::new(extern_crate.ident))
.is_none_or(|entry| entry.introduced_by_item)
.is_none_or(|entry| entry.introduced_by_item())
{
continue;
}

5
compiler/rustc_resolve/src/diagnostics.rs
View file

@ -322,7 +322,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
let from_item = self
.extern_prelude
.get(&Macros20NormalizedIdent::new(ident))
.is_none_or(|entry| entry.introduced_by_item);
.is_none_or(|entry| entry.introduced_by_item());
// Only suggest removing an import if both bindings are to the same def, if both spans
// aren't dummy spans. Further, if both bindings are imports, then the ident must have
// been introduced by an item.
@ -1845,7 +1845,8 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
let AmbiguityError { kind, ident, b1, b2, misc1, misc2, .. } = *ambiguity_error;
let extern_prelude_ambiguity = || {
self.extern_prelude.get(&Macros20NormalizedIdent::new(ident)).is_some_and(|entry| {
entry.item_binding == Some(b1) && entry.flag_binding.get() == Some(b2)
entry.item_binding.map(|(b, _)| b) == Some(b1)
&& entry.flag_binding.as_ref().and_then(|pb| pb.get().binding()) == Some(b2)
})
};
let (b1, b2, misc1, misc2, swapped) = if b2.span.is_dummy() && !b1.span.is_dummy() {

95
compiler/rustc_resolve/src/lib.rs
View file

@ -32,7 +32,7 @@ use std::sync::Arc;
use diagnostics::{ImportSuggestion, LabelSuggestion, Suggestion};
use effective_visibilities::EffectiveVisibilitiesVisitor;
use errors::{ParamKindInEnumDiscriminant, ParamKindInNonTrivialAnonConst};
use imports::{Import, ImportData, ImportKind, NameResolution};
use imports::{Import, ImportData, ImportKind, NameResolution, PendingBinding};
use late::{
ForwardGenericParamBanReason, HasGenericParams, PathSource, PatternSource,
UnnecessaryQualification,
@ -1025,18 +1025,26 @@ impl<'ra> NameBindingData<'ra> {
}
}
#[derive(Default, Clone)]
struct ExternPreludeEntry<'ra> {
/// Binding from an `extern crate` item.
item_binding: Option<NameBinding<'ra>>,
/// The boolean flag is true is `item_binding` is non-redundant, happens either when
/// `flag_binding` is `None`, or when `extern crate` introducing `item_binding` used renaming.
item_binding: Option<(NameBinding<'ra>, /* introduced by item */ bool)>,
/// Binding from an `--extern` flag, lazily populated on first use.
flag_binding: Cell<Option<NameBinding<'ra>>>,
/// There was no `--extern` flag introducing this name,
/// `flag_binding` doesn't need to be populated.
only_item: bool,
/// `item_binding` is non-redundant, happens either when `only_item` is true,
/// or when `extern crate` introducing `item_binding` used renaming.
introduced_by_item: bool,
flag_binding: Option<Cell<PendingBinding<'ra>>>,
}
impl ExternPreludeEntry<'_> {
fn introduced_by_item(&self) -> bool {
matches!(self.item_binding, Some((_, true)))
}
fn flag() -> Self {
ExternPreludeEntry {
item_binding: None,
flag_binding: Some(Cell::new(PendingBinding::Pending)),
}
}
}
struct DeriveData {
@ -1528,7 +1536,8 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
&& let name = Symbol::intern(name)
&& name.can_be_raw()
{
Some((Macros20NormalizedIdent::with_dummy_span(name), Default::default()))
let ident = Macros20NormalizedIdent::with_dummy_span(name);
Some((ident, ExternPreludeEntry::flag()))
} else {
None
}
@ -1536,11 +1545,11 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
.collect();
if !attr::contains_name(attrs, sym::no_core) {
extern_prelude
.insert(Macros20NormalizedIdent::with_dummy_span(sym::core), Default::default());
let ident = Macros20NormalizedIdent::with_dummy_span(sym::core);
extern_prelude.insert(ident, ExternPreludeEntry::flag());
if !attr::contains_name(attrs, sym::no_std) {
extern_prelude
.insert(Macros20NormalizedIdent::with_dummy_span(sym::std), Default::default());
let ident = Macros20NormalizedIdent::with_dummy_span(sym::std);
extern_prelude.insert(ident, ExternPreludeEntry::flag());
}
}
@ -2062,12 +2071,11 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
}
// Avoid marking `extern crate` items that refer to a name from extern prelude,
// but not introduce it, as used if they are accessed from lexical scope.
if used == Used::Scope {
if let Some(entry) = self.extern_prelude.get(&Macros20NormalizedIdent::new(ident)) {
if !entry.introduced_by_item && entry.item_binding == Some(used_binding) {
return;
}
}
if used == Used::Scope
&& let Some(entry) = self.extern_prelude.get(&Macros20NormalizedIdent::new(ident))
&& entry.item_binding == Some((used_binding, false))
{
return;
}
let old_used = self.import_use_map.entry(import).or_insert(used);
if *old_used < used {
@ -2226,7 +2234,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
finalize: bool,
) -> Option<NameBinding<'ra>> {
let entry = self.extern_prelude.get(&Macros20NormalizedIdent::new(ident));
entry.and_then(|entry| entry.item_binding).map(|binding| {
entry.and_then(|entry| entry.item_binding).map(|(binding, _)| {
if finalize {
self.get_mut().record_use(ident, binding, Used::Scope);
}
@ -2236,31 +2244,28 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
fn extern_prelude_get_flag(&self, ident: Ident, finalize: bool) -> Option<NameBinding<'ra>> {
let entry = self.extern_prelude.get(&Macros20NormalizedIdent::new(ident));
entry.and_then(|entry| match entry.flag_binding.get() {
Some(binding) => {
if finalize {
self.cstore_mut().process_path_extern(self.tcx, ident.name, ident.span);
}
Some(binding)
}
None if entry.only_item => None,
None => {
let crate_id = if finalize {
self.cstore_mut().process_path_extern(self.tcx, ident.name, ident.span)
} else {
self.cstore_mut().maybe_process_path_extern(self.tcx, ident.name)
};
match crate_id {
Some(crate_id) => {
let res = Res::Def(DefKind::Mod, crate_id.as_def_id());
let binding =
self.arenas.new_pub_res_binding(res, DUMMY_SP, LocalExpnId::ROOT);
entry.flag_binding.set(Some(binding));
Some(binding)
entry.and_then(|entry| entry.flag_binding.as_ref()).and_then(|flag_binding| {
let binding = match flag_binding.get() {
PendingBinding::Ready(binding) => {
if finalize {
self.cstore_mut().process_path_extern(self.tcx, ident.name, ident.span);
}
None => finalize.then_some(self.dummy_binding),
binding
}
}
PendingBinding::Pending => {
let crate_id = if finalize {
self.cstore_mut().process_path_extern(self.tcx, ident.name, ident.span)
} else {
self.cstore_mut().maybe_process_path_extern(self.tcx, ident.name)
};
crate_id.map(|crate_id| {
let res = Res::Def(DefKind::Mod, crate_id.as_def_id());
self.arenas.new_pub_res_binding(res, DUMMY_SP, LocalExpnId::ROOT)
})
}
};
flag_binding.set(PendingBinding::Ready(binding));
binding.or_else(|| finalize.then_some(self.dummy_binding))
})
}