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Diffstat (limited to '')
-rw-r--r-- | compiler/rustc_passes/src/diagnostic_items.rs | 113 |
1 files changed, 113 insertions, 0 deletions
diff --git a/compiler/rustc_passes/src/diagnostic_items.rs b/compiler/rustc_passes/src/diagnostic_items.rs new file mode 100644 index 000000000..e6b69d898 --- /dev/null +++ b/compiler/rustc_passes/src/diagnostic_items.rs @@ -0,0 +1,113 @@ +//! 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_middle::ty::query::Providers; +use rustc_middle::ty::TyCtxt; +use rustc_span::def_id::{CrateNum, DefId, LocalDefId, LOCAL_CRATE}; +use rustc_span::symbol::{sym, Symbol}; + +fn observe_item<'tcx>( + tcx: TyCtxt<'tcx>, + diagnostic_items: &mut DiagnosticItems, + def_id: LocalDefId, +) { + let hir_id = tcx.hir().local_def_id_to_hir_id(def_id); + let attrs = tcx.hir().attrs(hir_id); + if let Some(name) = extract(attrs) { + // insert into our table + collect_item(tcx, diagnostic_items, name, def_id.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 { + let mut err = match tcx.hir().span_if_local(item_def_id) { + Some(span) => tcx + .sess + .struct_span_err(span, &format!("duplicate diagnostic item found: `{name}`.")), + None => tcx.sess.struct_err(&format!( + "duplicate diagnostic item in crate `{}`: `{}`.", + tcx.crate_name(item_def_id.krate), + name + )), + }; + if let Some(span) = tcx.hir().span_if_local(original_def_id) { + err.span_note(span, "the diagnostic item is first defined here"); + } else { + err.note(&format!( + "the diagnostic item is first defined in crate `{}`.", + tcx.crate_name(original_def_id.krate) + )); + } + err.emit(); + } + } +} + +/// 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>(tcx: TyCtxt<'tcx>, cnum: CrateNum) -> DiagnosticItems { + assert_eq!(cnum, LOCAL_CRATE); + + // 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.items() { + observe_item(tcx, &mut diagnostic_items, id.def_id); + } + + for id in crate_items.trait_items() { + observe_item(tcx, &mut diagnostic_items, id.def_id); + } + + for id in crate_items.impl_items() { + observe_item(tcx, &mut diagnostic_items, id.def_id); + } + + for id in crate_items.foreign_items() { + observe_item(tcx, &mut diagnostic_items, id.def_id); + } + + diagnostic_items +} + +/// Traverse and collect all the diagnostic items in all crates. +fn all_diagnostic_items<'tcx>(tcx: TyCtxt<'tcx>, (): ()) -> 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; +} |