Use HirId in TraitCandidate.

src/librustc/ich/impls_hir.rs

@@ -270,7 +270,6 @@ impl<'a> ToStableHashKey<StableHashingContext<'a>> for hir::TraitCandidate {
 
         let import_keys = import_ids
             .iter()
-            .map(|node_id| hcx.node_to_hir_id(*node_id))
             .map(|hir_id| (hcx.local_def_path_hash(hir_id.owner), hir_id.local_id))
             .collect();
         (hcx.def_path_hash(*def_id), import_keys)

src/librustc/ty/context.rs

@@ -1161,6 +1161,10 @@ impl<'tcx> TyCtxt<'tcx> {
         for (k, v) in resolutions.trait_map {
             let hir_id = hir.node_to_hir_id(k);
             let map = trait_map.entry(hir_id.owner).or_default();
+            let v = v
+                .into_iter()
+                .map(|tc| tc.map_import_ids(|id| hir.definitions().node_to_hir_id(id)))
+                .collect();
             map.insert(hir_id.local_id, StableVec::new(v));
         }
 

src/librustc/ty/mod.rs

@@ -126,7 +126,7 @@ pub struct ResolverOutputs {
     pub definitions: hir_map::Definitions,
     pub cstore: Box<CrateStoreDyn>,
     pub extern_crate_map: NodeMap<CrateNum>,
-    pub trait_map: TraitMap,
+    pub trait_map: TraitMap<NodeId>,
     pub maybe_unused_trait_imports: NodeSet,
     pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
     pub export_map: ExportMap<NodeId>,

src/librustc_hir/hir.rs

@@ -16,7 +16,7 @@ use rustc_span::source_map::{SourceMap, Spanned};
 use rustc_span::symbol::{kw, sym, Symbol};
 use rustc_span::{MultiSpan, Span, DUMMY_SP};
 use rustc_target::spec::abi::Abi;
-use syntax::ast::{self, AsmDialect, CrateSugar, Ident, Name, NodeId};
+use syntax::ast::{self, AsmDialect, CrateSugar, Ident, Name};
 use syntax::ast::{AttrVec, Attribute, FloatTy, IntTy, Label, LitKind, StrStyle, UintTy};
 pub use syntax::ast::{BorrowKind, ImplPolarity, IsAuto};
 pub use syntax::ast::{CaptureBy, Movability, Mutability};
@@ -2608,13 +2608,24 @@ pub type CaptureModeMap = NodeMap<CaptureBy>;
 // has length > 0 if the trait is found through an chain of imports, starting with the
 // import/use statement in the scope where the trait is used.
 #[derive(Clone, Debug)]
-pub struct TraitCandidate {
+pub struct TraitCandidate<ID = HirId> {
     pub def_id: DefId,
-    pub import_ids: SmallVec<[NodeId; 1]>,
+    pub import_ids: SmallVec<[ID; 1]>,
+}
+
+impl<ID> TraitCandidate<ID> {
+    pub fn map_import_ids<F, T>(self, f: F) -> TraitCandidate<T>
+    where
+        F: Fn(ID) -> T,
+    {
+        let TraitCandidate { def_id, import_ids } = self;
+        let import_ids = import_ids.into_iter().map(f).collect();
+        TraitCandidate { def_id, import_ids }
+    }
 }
 
 // Trait method resolution
-pub type TraitMap = NodeMap<Vec<TraitCandidate>>;
+pub type TraitMap<ID = HirId> = NodeMap<Vec<TraitCandidate<ID>>>;
 
 // Map from the NodeId of a glob import to a list of items which are actually
 // imported.

src/librustc_resolve/late.rs

@@ -2078,7 +2078,7 @@ impl<'a, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
         &mut self,
         mut ident: Ident,
         ns: Namespace,
-    ) -> Vec<TraitCandidate> {
+    ) -> Vec<TraitCandidate<NodeId>> {
         debug!("(getting traits containing item) looking for '{}'", ident.name);
 
         let mut found_traits = Vec::new();
@@ -2123,7 +2123,7 @@ impl<'a, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
         ident: Ident,
         ns: Namespace,
         module: Module<'a>,
-        found_traits: &mut Vec<TraitCandidate>,
+        found_traits: &mut Vec<TraitCandidate<NodeId>>,
     ) {
         assert!(ns == TypeNS || ns == ValueNS);
         let mut traits = module.traits.borrow_mut();

src/librustc_resolve/lib.rs

@@ -865,7 +865,7 @@ pub struct Resolver<'a> {
     /// `CrateNum` resolutions of `extern crate` items.
     extern_crate_map: NodeMap<CrateNum>,
     export_map: ExportMap<NodeId>,
-    trait_map: TraitMap,
+    trait_map: TraitMap<NodeId>,
 
     /// A map from nodes to anonymous modules.
     /// Anonymous modules are pseudo-modules that are implicitly created around items

src/librustc_typeck/check/method/probe.rs

@@ -902,13 +902,10 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
             for trait_candidate in applicable_traits.iter() {
                 let trait_did = trait_candidate.def_id;
                 if duplicates.insert(trait_did) {
-                    let import_ids = trait_candidate
-                        .import_ids
-                        .iter()
-                        .map(|node_id| self.fcx.tcx.hir().node_to_hir_id(*node_id))
-                        .collect();
-                    let result =
-                        self.assemble_extension_candidates_for_trait(import_ids, trait_did);
+                    let result = self.assemble_extension_candidates_for_trait(
+                        &trait_candidate.import_ids,
+                        trait_did,
+                    );
                     result?;
                 }
             }
@@ -920,7 +917,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
         let mut duplicates = FxHashSet::default();
         for trait_info in suggest::all_traits(self.tcx) {
             if duplicates.insert(trait_info.def_id) {
-                self.assemble_extension_candidates_for_trait(smallvec![], trait_info.def_id)?;
+                self.assemble_extension_candidates_for_trait(&smallvec![], trait_info.def_id)?;
             }
         }
         Ok(())
@@ -959,7 +956,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
 
     fn assemble_extension_candidates_for_trait(
         &mut self,
-        import_ids: SmallVec<[hir::HirId; 1]>,
+        import_ids: &SmallVec<[hir::HirId; 1]>,
         trait_def_id: DefId,
     ) -> Result<(), MethodError<'tcx>> {
         debug!("assemble_extension_candidates_for_trait(trait_def_id={:?})", trait_def_id);