diff --git a/clang-tools-extra/clangd/index/FileIndex.cpp b/clang-tools-extra/clangd/index/FileIndex.cpp
--- a/clang-tools-extra/clangd/index/FileIndex.cpp
+++ b/clang-tools-extra/clangd/index/FileIndex.cpp
@@ -274,24 +274,34 @@
   std::vector<RefSlab *> MainFileRefs;
   {
     std::lock_guard<std::mutex> Lock(Mutex);
-    for (const auto &FileAndSymbols : SymbolsSnapshot) {
+    for (const auto &FileAndSymbols : SymbolsSnapshot)
       SymbolSlabs.push_back(FileAndSymbols.second);
-      Files.insert(FileAndSymbols.first());
-    }
     for (const auto &FileAndRefs : RefsSnapshot) {
       RefSlabs.push_back(FileAndRefs.second.Slab);
-      Files.insert(FileAndRefs.first());
       if (FileAndRefs.second.CountReferences)
         MainFileRefs.push_back(RefSlabs.back().get());
     }
-    for (const auto &FileAndRelations : RelationsSnapshot) {
-      Files.insert(FileAndRelations.first());
+    for (const auto &FileAndRelations : RelationsSnapshot)
       RelationSlabs.push_back(FileAndRelations.second);
-    }
 
     if (Version)
       *Version = this->Version;
   }
+  for (const auto &Slab : SymbolSlabs) {
+    for (const auto &Sym : *Slab) {
+      if (Sym.Definition)
+        Files.insert(Sym.Definition.FileURI);
+      else
+        Files.insert(Sym.CanonicalDeclaration.FileURI);
+    }
+  }
+  for (const auto &Slab : RefSlabs) {
+    for (const auto &Refs : *Slab) {
+      for (const auto &Ref : Refs.second)
+        Files.insert(Ref.Location.FileURI);
+    }
+  }
+
   std::vector<const Symbol *> AllSymbols;
   std::vector<Symbol> SymsStorage;
   switch (DuplicateHandle) {
diff --git a/clang-tools-extra/clangd/index/MemIndex.cpp b/clang-tools-extra/clangd/index/MemIndex.cpp
--- a/clang-tools-extra/clangd/index/MemIndex.cpp
+++ b/clang-tools-extra/clangd/index/MemIndex.cpp
@@ -112,14 +112,7 @@
 llvm::unique_function<IndexContents(llvm::StringRef) const>
 MemIndex::indexedFiles() const {
   return [this](llvm::StringRef FileURI) {
-    if (Files.empty())
-      return IndexContents::None;
-    auto Path = URI::resolve(FileURI, Files.begin()->first());
-    if (!Path) {
-      vlog("Failed to resolve the URI {0} : {1}", FileURI, Path.takeError());
-      return IndexContents::None;
-    }
-    return Files.contains(*Path) ? IdxContents : IndexContents::None;
+    return Files.contains(FileURI) ? IdxContents : IndexContents::None;
   };
 }
 
diff --git a/clang-tools-extra/clangd/index/dex/Dex.cpp b/clang-tools-extra/clangd/index/dex/Dex.cpp
--- a/clang-tools-extra/clangd/index/dex/Dex.cpp
+++ b/clang-tools-extra/clangd/index/dex/Dex.cpp
@@ -316,14 +316,7 @@
 llvm::unique_function<IndexContents(llvm::StringRef) const>
 Dex::indexedFiles() const {
   return [this](llvm::StringRef FileURI) {
-    if (Files.empty())
-      return IndexContents::None;
-    auto Path = URI::resolve(FileURI, Files.begin()->first());
-    if (!Path) {
-      vlog("Failed to resolve the URI {0} : {1}", FileURI, Path.takeError());
-      return IndexContents::None;
-    }
-    return Files.contains(*Path) ? IdxContents : IndexContents::None;
+    return Files.contains(FileURI) ? IdxContents : IndexContents::None;
   };
 }
 
diff --git a/clang-tools-extra/clangd/unittests/DexTests.cpp b/clang-tools-extra/clangd/unittests/DexTests.cpp
--- a/clang-tools-extra/clangd/unittests/DexTests.cpp
+++ b/clang-tools-extra/clangd/unittests/DexTests.cpp
@@ -737,7 +737,7 @@
   RefSlab Refs;
   auto Size = Symbols.bytes() + Refs.bytes();
   auto Data = std::make_pair(std::move(Symbols), std::move(Refs));
-  llvm::StringSet<> Files = {testPath("foo.cc"), testPath("bar.cc")};
+  llvm::StringSet<> Files = {"unittest:///foo.cc", "unittest:///bar.cc"};
   Dex I(std::move(Data.first), std::move(Data.second), RelationSlab(),
         std::move(Files), IndexContents::All, std::move(Data), Size);
   auto ContainsFile = I.indexedFiles();
diff --git a/clang-tools-extra/clangd/unittests/IndexTests.cpp b/clang-tools-extra/clangd/unittests/IndexTests.cpp
--- a/clang-tools-extra/clangd/unittests/IndexTests.cpp
+++ b/clang-tools-extra/clangd/unittests/IndexTests.cpp
@@ -229,7 +229,7 @@
   RefSlab Refs;
   auto Size = Symbols.bytes() + Refs.bytes();
   auto Data = std::make_pair(std::move(Symbols), std::move(Refs));
-  llvm::StringSet<> Files = {testPath("foo.cc"), testPath("bar.cc")};
+  llvm::StringSet<> Files = {"unittest:///foo.cc", "unittest:///bar.cc"};
   MemIndex I(std::move(Data.first), std::move(Data.second), RelationSlab(),
              std::move(Files), IndexContents::All, std::move(Data), Size);
   auto ContainsFile = I.indexedFiles();
@@ -339,21 +339,21 @@
   FileIndex DynamicIndex, StaticIndex;
   MergedIndex Merge(&DynamicIndex, &StaticIndex);
 
-  const char *HeaderCode = "class Foo;";
+  const char *HeaderCode = "class Foo; class Bar;";
   auto HeaderSymbols = TestTU::withHeaderCode(HeaderCode).headerSymbols();
   auto Foo = findSymbol(HeaderSymbols, "Foo");
 
-  // Build static index for test.cc with Foo symbol
+  // Build static index for test.cc with Foo and Bar symbols
   TestTU Test;
   Test.HeaderCode = HeaderCode;
-  Test.Code = "class Foo {};";
+  Test.Code = "class Foo {}; class Bar {};";
   Test.Filename = "test.cc";
   auto AST = Test.build();
   StaticIndex.updateMain(testPath(Test.Filename), AST);
 
-  // Remove Foo symbol, i.e. build dynamic index for test.cc, which is empty.
-  Test.HeaderCode = "";
-  Test.Code = "";
+  // Remove Foo symbol.
+  Test.HeaderCode = "class Bar;";
+  Test.Code = "class Bar {};";
   AST = Test.build();
   DynamicIndex.updateMain(testPath(Test.Filename), AST);
 
@@ -487,7 +487,7 @@
 
   // Remove all refs for test.cc from dynamic index,
   // merged index should not return results from static index for test.cc.
-  Test.Code = "";
+  Test.Code = "int I;"; // test.cc should not be empty
   AST = Test.build();
   Dyn.updateMain(testPath(Test.Filename), AST);
 
@@ -506,7 +506,7 @@
   RefSlab DynRefs;
   auto DynSize = DynSymbols.bytes() + DynRefs.bytes();
   auto DynData = std::make_pair(std::move(DynSymbols), std::move(DynRefs));
-  llvm::StringSet<> DynFiles = {testPath("foo.cc")};
+  llvm::StringSet<> DynFiles = {"unittest:///foo.cc"};
   MemIndex DynIndex(std::move(DynData.first), std::move(DynData.second),
                     RelationSlab(), std::move(DynFiles), IndexContents::Symbols,
                     std::move(DynData), DynSize);
@@ -514,7 +514,7 @@
   RefSlab StaticRefs;
   auto StaticData =
       std::make_pair(std::move(StaticSymbols), std::move(StaticRefs));
-  llvm::StringSet<> StaticFiles = {testPath("foo.cc"), testPath("bar.cc")};
+  llvm::StringSet<> StaticFiles = {"unittest:///foo.cc", "unittest:///bar.cc"};
   MemIndex StaticIndex(
       std::move(StaticData.first), std::move(StaticData.second), RelationSlab(),
       std::move(StaticFiles), IndexContents::References, std::move(StaticData),