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//! Detecting diagnostic items.
//!
//! Diagnostic items are items that are not language-inherent, but can reasonably be expected to
//! exist for diagnostic purposes. This allows diagnostic authors to refer to specific items
//! directly, without having to guess module paths and crates.
//! Examples are:
//!
//! * Traits like `Debug`, that have no bearing on language semantics
//!
//! * Compiler internal types like `Ty` and `TyCtxt`
use rustc_ast as ast;
use rustc_hir::diagnostic_items::DiagnosticItems;
use rustc_hir::OwnerId;
use rustc_middle::query::LocalCrate;
use rustc_middle::query::Providers;
use rustc_middle::ty::TyCtxt;
use rustc_span::def_id::{DefId, LOCAL_CRATE};
use rustc_span::symbol::{sym, Symbol};
use crate::errors::DuplicateDiagnosticItemInCrate;
fn observe_item<'tcx>(tcx: TyCtxt<'tcx>, diagnostic_items: &mut DiagnosticItems, owner: OwnerId) {
let attrs = tcx.hir().attrs(owner.into());
if let Some(name) = extract(attrs) {
// insert into our table
collect_item(tcx, diagnostic_items, name, owner.to_def_id());
}
}
fn collect_item(tcx: TyCtxt<'_>, items: &mut DiagnosticItems, name: Symbol, item_def_id: DefId) {
items.id_to_name.insert(item_def_id, name);
if let Some(original_def_id) = items.name_to_id.insert(name, item_def_id) {
if original_def_id != item_def_id {
report_duplicate_item(tcx, name, original_def_id, item_def_id);
}
}
}
fn report_duplicate_item(
tcx: TyCtxt<'_>,
name: Symbol,
original_def_id: DefId,
item_def_id: DefId,
) {
let orig_span = tcx.hir().span_if_local(original_def_id);
let duplicate_span = tcx.hir().span_if_local(item_def_id);
tcx.sess.emit_err(DuplicateDiagnosticItemInCrate {
duplicate_span,
orig_span,
crate_name: tcx.crate_name(item_def_id.krate),
orig_crate_name: tcx.crate_name(original_def_id.krate),
different_crates: (item_def_id.krate != original_def_id.krate).then_some(()),
name,
});
}
/// Extract the first `rustc_diagnostic_item = "$name"` out of a list of attributes.
fn extract(attrs: &[ast::Attribute]) -> Option<Symbol> {
attrs.iter().find_map(|attr| {
if attr.has_name(sym::rustc_diagnostic_item) { attr.value_str() } else { None }
})
}
/// Traverse and collect the diagnostic items in the current
fn diagnostic_items(tcx: TyCtxt<'_>, _: LocalCrate) -> DiagnosticItems {
// Initialize the collector.
let mut diagnostic_items = DiagnosticItems::default();
// Collect diagnostic items in this crate.
let crate_items = tcx.hir_crate_items(());
for id in crate_items.owners() {
observe_item(tcx, &mut diagnostic_items, id);
}
diagnostic_items
}
/// Traverse and collect all the diagnostic items in all crates.
fn all_diagnostic_items(tcx: TyCtxt<'_>, (): ()) -> DiagnosticItems {
// Initialize the collector.
let mut items = DiagnosticItems::default();
// Collect diagnostic items in other crates.
for &cnum in tcx.crates(()).iter().chain(std::iter::once(&LOCAL_CRATE)) {
for (&name, &def_id) in &tcx.diagnostic_items(cnum).name_to_id {
collect_item(tcx, &mut items, name, def_id);
}
}
items
}
pub fn provide(providers: &mut Providers) {
providers.diagnostic_items = diagnostic_items;
providers.all_diagnostic_items = all_diagnostic_items;
}
|
