fix(cxx_indexer): address issue #5935 (when aliasing is on) (#5937)

kythe · Nov 16, 2023 · 1ac7b16 · 1ac7b16
1 parent 7bb8054
commit 1ac7b16
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Showing 4 changed files with 32 additions and 8 deletions.
diff --git a/kythe/cxx/indexer/cxx/GraphObserver.h b/kythe/cxx/indexer/cxx/GraphObserver.h
@@ -190,6 +190,13 @@ class GraphObserver {
     }
     const std::string& getRawIdentity() const { return Identity; }
     const ClaimToken* getToken() const { return Token; }
+    /// \brief Create a derived NodeId from this one.
+    ///
+    /// This is meant for debugging. You'll likely want to disable
+    /// `ForceEncodeString` in GraphObserver.cc.
+    NodeId derive(const std::string& s) const {
+      return NodeId(Token, Identity + s);
+    }
 
    private:
     friend class GraphObserver;

diff --git a/kythe/cxx/indexer/cxx/IndexerASTHooks.cc b/kythe/cxx/indexer/cxx/IndexerASTHooks.cc
@@ -3756,6 +3756,15 @@ bool IndexerASTVisitor::VisitUsingShadowDecl(
     const clang::UsingShadowDecl* Decl) {
   if (auto RCC =
           ExplicitRangeInCurrentContext(RangeForNameOfDeclaration(Decl))) {
+    if (auto* ctd = llvm::dyn_cast_or_null<clang::ClassTemplateDecl>(
+            Decl->getTargetDecl());
+        ctd != nullptr && ctd->getTemplatedDecl() != nullptr &&
+        absl::GetFlag(FLAGS_experimental_alias_template_instantiations)) {
+      Observer.recordDeclUseLocation(
+          RCC.value(), BuildNodeIdForDecl(ctd->getTemplatedDecl()),
+          GraphObserver::Claimability::Claimable, IsImplicit(RCC.value()));
+      return true;
+    }
     Observer.recordDeclUseLocation(
         RCC.value(), BuildNodeIdForDecl(Decl->getTargetDecl()),
         GraphObserver::Claimability::Claimable, IsImplicit(RCC.value()));
@@ -4072,6 +4081,19 @@ IndexerASTVisitor::BuildNodeIdForTemplateName(const clang::TemplateName& Name) {
         LOG(FATAL) << "BuildNodeIdForTemplateName can't identify TemplateDecl";
       }
     }
+    case TemplateName::UsingTemplate: {
+      // UsingShadowDecl::getIntroducer() will return the specific
+      // using-declaration. We don't index UsingShadowDecls as definition sites,
+      // so it's not helpful to point at that declaration.
+      const clang::UsingShadowDecl* decl = Name.getAsUsingShadowDecl();
+      if (auto* ctd = llvm::dyn_cast_or_null<clang::ClassTemplateDecl>(
+              decl->getTargetDecl());
+          ctd != nullptr && ctd->getTemplatedDecl() != nullptr &&
+          absl::GetFlag(FLAGS_experimental_alias_template_instantiations)) {
+        return BuildNodeIdForDecl(ctd->getTemplatedDecl());
+      }
+      return BuildNodeIdForDecl(decl);
+    }
     case TemplateName::OverloadedTemplate:
       CHECK(options_.IgnoreUnimplemented) << "TN.OverloadedTemplate";
       return std::nullopt;
@@ -4090,9 +4112,6 @@ IndexerASTVisitor::BuildNodeIdForTemplateName(const clang::TemplateName& Name) {
     case TemplateName::SubstTemplateTemplateParmPack:
       CHECK(options_.IgnoreUnimplemented) << "TN.SubstTemplateTemplateParmPack";
       return std::nullopt;
-    case TemplateName::UsingTemplate:
-      CHECK(options_.IgnoreUnimplemented) << "TN.UsingTemplate";
-      return std::nullopt;
   }
   CHECK(options_.IgnoreUnimplemented)
       << "Unexpected TemplateName kind: " << Name.getKind();

diff --git a/kythe/cxx/indexer/cxx/testdata/BUILD b/kythe/cxx/indexer/cxx/testdata/BUILD
@@ -2741,7 +2741,6 @@ cc_indexer_test(
     srcs = ["template/template_using_name.cc"],
     experimental_alias_template_instantiations = True,
     ignore_dups = True,
-    ignore_unimplemented = True,
     tags = ["template"],
 )
 

diff --git a/kythe/cxx/indexer/cxx/testdata/template/template_using_name.cc b/kythe/cxx/indexer/cxx/testdata/template/template_using_name.cc
@@ -4,11 +4,10 @@ namespace ns {
 //- @S defines/binding TemplateS
 template <typename T> struct S {};
 }
-//- !{@S ref TemplateS}  // TODO(zrlk): Targets missing node.
+// NB: using declaration cannot refer to a template specialization
+//- @S ref TemplateS
 using ns::S;
-// This trips an unimplemented check (TN.UsingTemplate) in
-// BuildNodeIdForTemplateName
 //- @"S<int>" ref TemplateSInt
 //- TemplateSInt param.0 TemplateS
-//- !{@S ref TemplateS}  // TODO(zrlk): No anchor for S
+//- @S ref TemplateS
 S<int> s;