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resolve: Split extern prelude into two scopes

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One for `--extern` options and another for `extern crate` items.
This commit is contained in:
Vadim Petrochenkov
2025-08-01 18:07:59 +03:00
parent 350d0ef0ec
commit 772493d51d
14 changed files with 212 additions and 86 deletions
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21
compiler/rustc_resolve/src/build_reduced_graph.rs
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@@ -971,40 +971,35 @@ impl<'a, 'ra, 'tcx> BuildReducedGraphVisitor<'a, 'ra, 'tcx> {
let imported_binding = self.r.import(binding, import);
if ident.name != kw::Underscore && parent == self.r.graph_root {
let norm_ident = Macros20NormalizedIdent::new(ident);
// FIXME: this error is technically unnecessary now when extern prelude is split into
// two scopes, remove it with lang team approval.
if let Some(entry) = self.r.extern_prelude.get(&norm_ident)
&& expansion != LocalExpnId::ROOT
&& orig_name.is_some()
&& !entry.is_import()
&& entry.item_binding.is_none()
{
self.r.dcx().emit_err(
errors::MacroExpandedExternCrateCannotShadowExternArguments { span: item.span },
);
// `return` is intended to discard this binding because it's an
// unregistered ambiguity error which would result in a panic
// caused by inconsistency `path_res`
// more details: https://github.com/rust-lang/rust/pull/111761
return;
}
use indexmap::map::Entry;
match self.r.extern_prelude.entry(norm_ident) {
Entry::Occupied(mut occupied) => {
let entry = occupied.get_mut();
if let Some(old_binding) = entry.binding.get()
&& old_binding.is_import()
{
if entry.item_binding.is_some() {
let msg = format!("extern crate `{ident}` already in extern prelude");
self.r.tcx.dcx().span_delayed_bug(item.span, msg);
} else {
// Binding from `extern crate` item in source code can replace
// a binding from `--extern` on command line here.
entry.binding.set(Some(imported_binding));
entry.item_binding = Some(imported_binding);
entry.introduced_by_item = orig_name.is_some();
}
entry
}
Entry::Vacant(vacant) => vacant.insert(ExternPreludeEntry {
binding: Cell::new(Some(imported_binding)),
item_binding: Some(imported_binding),
flag_binding: Cell::new(None),
only_item: true,
introduced_by_item: true,
}),
};