[clangd] Fix a regression in rL366996.

[hokein]

Summary

That patch made the tweak always annotate the whole file by accident.

[hokein]

oops, forgot a change.

[jvikstrom]

clang-tools-extra/clangd/refactor/tweaks/AnnotateHighlightings.cpp

44

Shouldn't intently -> instantly?

[hokein]

clang-tools-extra/clangd/refactor/tweaks/AnnotateHighlightings.cpp

44

ah, I mean intendedly.

clang-tools-extra/clangd/refactor/tweaks/AnnotateHighlightings.cpp

public:
 
   std::string title() const override { return "Annotate highlighting tokens"; }
   Intent intent() const override { return Refactor; }
   bool hidden() const override { return true; }
 };
 REGISTER_TWEAK(AnnotateHighlightings)
 
 Expected<Tweak::Effect> AnnotateHighlightings::apply(const Selection &Inputs) {
-  // TUDecl is always the root ancestor.
-  const Decl *CommonDecl =
-      Inputs.ASTSelection.root().ASTNode.get<TranslationUnitDecl>();
+  const Decl *CommonDecl = nullptr;
   for (auto N = Inputs.ASTSelection.commonAncestor(); N && !CommonDecl;
        N = N->Parent)
     CommonDecl = N->ASTNode.get<Decl>();
 
   std::vector<HighlightingToken> HighlightingTokens;
   if (llvm::isa<TranslationUnitDecl>(CommonDecl)) {
-    // We only annotate tokens in the main file, if CommonDecl is a TUDecl,
-    // we use the default traversal scope (which is the top level decls of the
-    // main file).
+    // Now we hit the TUDecl case where commonAncestor() returns null intently.
+    // We only annotate tokens in the main file, so use the default traversal
+    // scope (which is the top level decls of the main file).
     HighlightingTokens = getSemanticHighlightings(Inputs.AST);
   } else {
     // Store the existing scopes.
     const auto &BackupScopes = Inputs.AST.getASTContext().getTraversalScope();
     // Narrow the traversal scope to the selected node.
     Inputs.AST.getASTContext().setTraversalScope(
         {const_cast<Decl *>(CommonDecl)});
     HighlightingTokens = getSemanticHighlightings(Inputs.AST);

clang-tools-extra/clangd/unittests/TweakTests.cpp

TEST(TweakTest, AnnotateHighlightings) {
   R"cpp(
 [[void f1();
 void f2();]]
 )cpp",
   R"cpp(
 void /* entity.name.function.cpp */f1();
 void /* entity.name.function.cpp */f2();
 )cpp");
+
+   checkTransform(ID,
+  R"cpp(
+void f1();
+void f2() {^};
+)cpp",
+
+  R"cpp(
+void f1();
+void /* entity.name.function.cpp */f2() {};
+)cpp");
 }
 
 TEST(TweakTest, ExpandMacro) {
   llvm::StringLiteral ID = "ExpandMacro";
 
   // Available on macro names, not available anywhere else.
   checkAvailable(ID, R"cpp(
 #define FOO 1 2 3