Uniquify textDocument/references

There can be duplicates with template instantiation.

src/indexer.cc

@@ -1113,8 +1113,6 @@ std::string IndexFile::ToString() {
   return ccls::Serialize(SerializeFormat::Json, *this);
 }
 
-MAKE_HASHABLE(Use, t.range, t.file_id)
-
 template <typename T>
 void Uniquify(std::vector<T>& a) {
   std::unordered_set<T> seen;

src/indexer.h

@@ -61,10 +61,11 @@ struct Use : Reference {
   // |file| is used in Query* but not in Index*
   int file_id = -1;
   bool operator==(const Use& o) const {
-    return range == o.range && usr == o.usr && kind == o.kind &&
-           role == o.role && file_id == o.file_id;
+    // lexical container info is ignored.
+    return range == o.range && file_id == o.file_id;
   }
 };
+MAKE_HASHABLE(Use, t.range, t.file_id)
 
 void Reflect(Reader& visitor, Reference& value);
 void Reflect(Writer& visitor, Reference& value);

src/messages/textDocument_references.cc

@@ -63,6 +63,7 @@ struct Handler_TextDocumentReferences
     Out_TextDocumentReferences out;
     out.id = request->id;
     bool container = g_config->xref.container;
+    std::unordered_set<Use> seen_uses;
 
     for (SymbolRef sym : FindSymbolsAtLocation(wfile, file, params.position)) {
       // Found symbol. Return references.
@@ -76,7 +77,8 @@ struct Handler_TextDocumentReferences
         stack.pop_back();
         auto fn = [&](Use use, lsSymbolKind parent_kind) {
           if (Role(use.role & params.context.role) == params.context.role &&
-              !(use.role & params.context.excludeRole))
+              !(use.role & params.context.excludeRole) &&
+              seen_uses.insert(use).second)
             if (std::optional<lsLocationEx> ls_loc =
                     GetLsLocationEx(db, working_files, use, container)) {
               if (container)

src/query.cc

@@ -12,9 +12,6 @@
 #include <unordered_map>
 #include <unordered_set>
 
-// Used by |REMOVE_ADD| so only |range| is needed.
-MAKE_HASHABLE(Use, t.range, t.file_id);
-
 namespace {
 
 void AssignFileId(const Lid2file_id &, int file_id, SymbolRef &ref) {