diff --git a/clang-tools-extra/clangd/index/SymbolCollector.cpp b/clang-tools-extra/clangd/index/SymbolCollector.cpp
--- a/clang-tools-extra/clangd/index/SymbolCollector.cpp
+++ b/clang-tools-extra/clangd/index/SymbolCollector.cpp
@@ -340,8 +340,9 @@
     // TU, because in practice they are definitions.
     BasicSymbol = addDeclaration(*OriginalDecl, std::move(*ID), IsMainFileOnly);
 
-  if (Roles & static_cast<unsigned>(index::SymbolRole::Definition))
-    addDefinition(*OriginalDecl, *BasicSymbol);
+  if (BasicSymbol != nullptr)
+    if (Roles & static_cast<unsigned>(index::SymbolRole::Definition))
+      addDefinition(*OriginalDecl, *BasicSymbol);
 
   return true;
 }
@@ -434,8 +435,8 @@
   S.SymInfo = index::getSymbolInfoForMacro(*MI);
   S.Origin = Opts.Origin;
   std::string FileURI;
-  // FIXME: use the result to filter out symbols.
-  shouldIndexFile(SM.getFileID(Loc));
+  if (!shouldIndexFile(SM.getFileID(Loc)))
+    return false;
   if (auto DeclLoc =
           getTokenLocation(DefLoc, SM, Opts, PP->getLangOpts(), FileURI))
     S.CanonicalDeclaration = *DeclLoc;
@@ -561,8 +562,8 @@
           const std::pair<SourceLocation, index::SymbolRoleSet> &LocAndRole,
           bool Spelled = false) {
         auto FileID = SM.getFileID(LocAndRole.first);
-        // FIXME: use the result to filter out references.
-        shouldIndexFile(FileID);
+        if (!shouldIndexFile(FileID))
+          return;
         if (auto FileURI = GetURI(FileID)) {
           auto Range =
               getTokenRange(LocAndRole.first, SM, ASTCtx->getLangOpts());
@@ -639,8 +640,8 @@
   std::string FileURI;
   auto Loc = nameLocation(ND, SM);
   assert(Loc.isValid() && "Invalid source location for NamedDecl");
-  // FIXME: use the result to filter out symbols.
-  shouldIndexFile(SM.getFileID(Loc));
+  if (!shouldIndexFile(SM.getFileID(Loc)))
+    return nullptr;
   if (auto DeclLoc =
           getTokenLocation(Loc, SM, Opts, ASTCtx->getLangOpts(), FileURI))
     S.CanonicalDeclaration = *DeclLoc;
@@ -699,8 +700,8 @@
   std::string FileURI;
   const auto &SM = ND.getASTContext().getSourceManager();
   auto Loc = nameLocation(ND, SM);
-  // FIXME: use the result to filter out symbols.
-  shouldIndexFile(SM.getFileID(Loc));
+  if (!shouldIndexFile(SM.getFileID(Loc)))
+    return;
   if (auto DefLoc =
           getTokenLocation(Loc, SM, Opts, ASTCtx->getLangOpts(), FileURI))
     S.Definition = *DefLoc;