Author: Christian Kandeler
Date: 2026-09-16T12:08:31+02:00
New Revision: fd63167bbd7f0193f21129abe49604b98f777cdc

URL: 
https://github.com/llvm/llvm-project/commit/fd63167bbd7f0193f21129abe49604b98f777cdc
DIFF: 
https://github.com/llvm/llvm-project/commit/fd63167bbd7f0193f21129abe49604b98f777cdc.diff

LOG: [clangd] Include the operator name in documentHighlight (#220518)

## Summary
- Placing the cursor on an overloaded operator's declaration (e.g.
`operator new`, `operator[]`) and requesting
`textDocument/documentHighlight` only highlighted the `operator` keyword
itself, not the name or symbol that follows it (`new`, `[]`, etc.), even
though that name is what's actually significant to the user.
- `ReferenceFinder` already splits some references into several spelled
tokens (used for Objective-C's split selector syntax); this reuses that
mechanism for the operator name too, extracting the tokens spelled in
the operator name's source range. This only applies to the declaration's
own occurrence.

## Test plan
- [x] `ninja check-clangd` passes
- [x] New cases added to `HighlightsTest.All` in
`clang-tools-extra/clangd/unittests/XRefsTests.cpp` covering `operator
new`, `operator delete` (clicking on either the keyword or the name),
and a multi-token operator (`operator()`)

Added: 
    

Modified: 
    clang-tools-extra/clangd/XRefs.cpp
    clang-tools-extra/clangd/unittests/XRefsTests.cpp

Removed: 
    


################################################################################
diff  --git a/clang-tools-extra/clangd/XRefs.cpp 
b/clang-tools-extra/clangd/XRefs.cpp
index 73d8eb5d00569..e68e6a08adce5 100644
--- a/clang-tools-extra/clangd/XRefs.cpp
+++ b/clang-tools-extra/clangd/XRefs.cpp
@@ -41,6 +41,7 @@
 #include "clang/AST/StmtCXX.h"
 #include "clang/AST/StmtVisitor.h"
 #include "clang/AST/Type.h"
+#include "clang/AST/TypeLoc.h"
 #include "clang/Basic/LLVM.h"
 #include "clang/Basic/Module.h"
 #include "clang/Basic/SourceLocation.h"
@@ -1014,6 +1015,110 @@ std::vector<DocumentLink> getDocumentLinks(ParsedAST 
&AST) {
 
 namespace {
 
+/// Returns the locations of the spelled tokens overlapping [Range.getBegin(),
+/// Range.getEnd()], in order. Returns an empty list unless both ends of
+/// \p Range are file locations in the same file: unlike a spelling or
+/// expansion location, a macro location isn't something TokenBuffer (or the
+/// FileID/offset arithmetic below) can make sense of, e.g. if part of an
+/// operator name comes from a macro (`#define PLUS + ... operator PLUS(int)`).
+llvm::SmallVector<SourceLocation, 4>
+tokensSpelledInRange(const syntax::TokenBuffer &TB, const SourceManager &SM,
+                     SourceRange Range) {
+  llvm::SmallVector<SourceLocation, 4> Locs;
+  if (Range.getBegin().isInvalid() || Range.getEnd().isInvalid() ||
+      !Range.getBegin().isFileID() || !Range.getEnd().isFileID())
+    return Locs;
+  FileID FID = SM.getFileID(Range.getBegin());
+  if (FID != SM.getFileID(Range.getEnd()))
+    return Locs;
+  unsigned EndOffset = SM.getFileOffset(Range.getEnd());
+  llvm::ArrayRef<syntax::Token> Toks = TB.spelledTokens(FID);
+  auto It = llvm::partition_point(Toks, [&](const syntax::Token &Tok) {
+    return SM.getFileOffset(Tok.location()) <
+           SM.getFileOffset(Range.getBegin());
+  });
+  for (; It != Toks.end() && SM.getFileOffset(It->location()) <= EndOffset;
+       ++It)
+    Locs.push_back(It->location());
+  return Locs;
+}
+
+/// If this occurrence is spelled as (part of) an "operator"-shaped name --
+/// `operator+`, `operator[]`, a literal operator like `operator""_x`, or a
+/// conversion operator like `operator int()` -- returns the location of the
+/// `operator` keyword followed by the locations of the tokens that make up
+/// the rest of the name, so callers can highlight (or otherwise report) the
+/// whole name instead of just the keyword. Returns an empty list otherwise,
+/// including when \p Loc is some other occurrence of \p D (e.g. an implicit
+/// operator call like `a + b`, which has no `operator` token to extend).
+llvm::SmallVector<SourceLocation, 4>
+operatorNameTokens(const Decl *D,
+                   const index::IndexDataConsumer::ASTNodeInfo &ASTNode,
+                   SourceLocation Loc, const syntax::TokenBuffer &TB,
+                   const SourceManager &SM) {
+  std::optional<DeclarationNameInfo> NameInfo;
+  if (auto *ME = llvm::dyn_cast_or_null<MemberExpr>(ASTNode.OrigE))
+    NameInfo = ME->getMemberNameInfo();
+  else if (auto *DRE = llvm::dyn_cast_or_null<DeclRefExpr>(ASTNode.OrigE))
+    NameInfo = DRE->getNameInfo();
+  else if (auto *DSME = llvm::dyn_cast_or_null<CXXDependentScopeMemberExpr>(
+               ASTNode.OrigE))
+    NameInfo = DSME->getMemberNameInfo();
+  else if (auto *DSDRE =
+               
llvm::dyn_cast_or_null<DependentScopeDeclRefExpr>(ASTNode.OrigE))
+    NameInfo = DSDRE->getNameInfo();
+  else if (auto *OE = llvm::dyn_cast_or_null<OverloadExpr>(ASTNode.OrigE))
+    // An UnresolvedMemberExpr/UnresolvedLookupExpr: overload resolution for
+    // this call is dependent (e.g. on a template parameter), so it reports a
+    // reference to every candidate at the same (real, spelled) location.
+    NameInfo = OE->getNameInfo();
+  else if (auto *FD = llvm::dyn_cast_or_null<FunctionDecl>(D))
+    NameInfo = FD->getNameInfo();
+  // Not every occurrence carries its own name info. Most ways of invoking an
+  // operator without writing the `operator` keyword (e.g. `a + b`) still
+  // reference it through a real, if implicit, MemberExpr/DeclRefExpr callee
+  // that's handled by the cases above (and later filtered out below, since
+  // that implicit callee has no `operator` text to report). A `new T(...)`
+  // or `delete p;` *expression* is the odd one out: unlike a call, it has no
+  // callee sub-expression at all -- CXXNewExpr/CXXDeleteExpr just store the
+  // resolved FunctionDecl directly -- so indexing it passes no RefE, and we
+  // fall through to D's info above. There, NameInfo does not actually
+  // describe how the name is spelled at *this* occurrence -- it may belong
+  // to a distant reference, or even a declaration in another file entirely
+  // -- so its location won't match Loc.
+  if (!NameInfo || NameInfo->getLoc() != Loc)
+    return {};
+
+  SourceRange ExtraRange;
+  switch (NameInfo->getName().getNameKind()) {
+  case DeclarationName::CXXOperatorName:
+    ExtraRange = NameInfo->getCXXOperatorNameRange();
+    break;
+  case DeclarationName::CXXLiteralOperatorName: {
+    // The suffix (e.g. `_test` in `operator""_test`) is lexed as part of a
+    // single string-literal-with-suffix token, so its location isn't a
+    // token's own start; look up the (whole) token that contains it.
+    SourceLocation SuffixLoc = NameInfo->getCXXLiteralOperatorNameLoc();
+    if (SuffixLoc.isValid())
+      if (const auto *Tok = 
TB.spelledTokenContaining(SM.getFileLoc(SuffixLoc)))
+        ExtraRange = SourceRange(Tok->location(), Tok->location());
+    break;
+  }
+  case DeclarationName::CXXConversionFunctionName:
+    if (TypeSourceInfo *TInfo = NameInfo->getNamedTypeInfo())
+      ExtraRange = TInfo->getTypeLoc().getSourceRange();
+    break;
+  default:
+    break;
+  }
+  if (ExtraRange.getBegin().isInvalid())
+    return {};
+
+  llvm::SmallVector<SourceLocation, 4> Result{Loc};
+  llvm::append_range(Result, tokensSpelledInRange(TB, SM, ExtraRange));
+  return Result;
+}
+
 /// Collects references to symbols within the main file.
 class ReferenceFinder : public index::IndexDataConsumer {
 public:
@@ -1091,6 +1196,13 @@ class ReferenceFinder : public index::IndexDataConsumer {
       } else if (auto *OMD =
                      llvm::dyn_cast_or_null<ObjCMethodDecl>(ASTNode.OrigD)) {
         OMD->getSelectorLocs(Locs);
+      } else {
+        // An "operator"-shaped name (operator+, operator""_x, operator
+        // int()) has a name that's a separate token (or tokens) from the
+        // `operator` keyword itself; report both so the whole name gets
+        // highlighted, not just the keyword. This covers both the
+        // declaration and explicit references to it, e.g. `a.operator+(b)`.
+        Locs = operatorNameTokens(D, ASTNode, Loc, TB, SM);
       }
       // Sanity check: we expect the *first* token to match the reported loc.
       // Otherwise, maybe it was e.g. some other kind of reference to a Decl.

diff  --git a/clang-tools-extra/clangd/unittests/XRefsTests.cpp 
b/clang-tools-extra/clangd/unittests/XRefsTests.cpp
index d5ba2bc093c9c..9d1a34f23955c 100644
--- a/clang-tools-extra/clangd/unittests/XRefsTests.cpp
+++ b/clang-tools-extra/clangd/unittests/XRefsTests.cpp
@@ -135,6 +135,70 @@ TEST(HighlightsTest, All) {
             return 1;
         }
       )cpp",
+      R"cpp(// Overloaded operator: the whole name, not just `operator`, is 
highlighted.
+        using size_t = decltype(sizeof(0));
+        struct S {
+          static void *[[operator]] [[n^ew]](size_t);
+          static void operator delete(void *);
+        };
+      )cpp",
+      R"cpp(// Same, with the cursor on the operator keyword itself.
+        using size_t = decltype(sizeof(0));
+        struct S {
+          static void *[[^operator]] [[new]](size_t);
+          static void operator delete(void *);
+        };
+      )cpp",
+      R"cpp(// Same, for operator delete.
+        using size_t = decltype(sizeof(0));
+        struct S {
+          static void *operator new(size_t);
+          static void [[operator]] [[del^ete]](void *);
+        };
+      )cpp",
+      R"cpp(// Overloaded operator spanning multiple tokens.
+        struct S {
+          void [[operator]] [[^(]][[)]](int);
+        };
+      )cpp",
+      R"cpp(// Explicit operator-call syntax also highlights the whole name.
+        struct S {
+          S [[operator]] [[+]](S);
+        };
+        void f(S a) {
+          a.[[operator]] [[^+]](a);
+        }
+      )cpp",
+      R"cpp(// Literal operator: the suffix is lexed together with the 
preceding
+        // `""` as a single token, so the whole thing is highlighted.
+        long double [[operator]] [[""_te^st]](long double);
+      )cpp",
+      R"cpp(// Conversion operator: the target type name is highlighted too.
+        // (Clicking on `int` itself doesn't resolve to the declaration at
+        // all, a separate limitation.)
+        struct S {
+          [[^operator]] [[int]]();
+        };
+      )cpp",
+      R"cpp(// Regression: an operator name coming from a macro expansion must 
not
+        // crash. Since a macro location isn't something we can safely treat
+        // as spelled tokens, we fall back to highlighting just `operator`.
+        #define PLUS +
+        struct S { void [[operator]] PLU^S(int); };
+      )cpp",
+      R"cpp(// Regression: an overloaded operator called with dependent 
arguments
+        // (so overload resolution is deferred, producing an
+        // UnresolvedMemberExpr with several candidates at one location)
+        // should still have its whole name highlighted, not just `operator`.
+        struct S {
+          void operator+(int);
+          void [[operat^or]] [[+]](double);
+        };
+        template <typename T>
+        void foo(S s, T t) {
+          s.[[operator]] [[+]](t);
+        }
+      )cpp",
   };
   for (const char *Test : Tests) {
     Annotations T(Test);


        
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