Index: clangd/Quality.cpp
===================================================================
--- clangd/Quality.cpp
+++ clangd/Quality.cpp
@@ -41,6 +41,17 @@
   return false;
 }
 
+static bool hasUsingDeclInMainFile(const CodeCompletionResult &R) {
+  const auto &Context = R.Declaration->getASTContext();
+  const auto &SourceMgr = Context.getSourceManager();
+  if (R.ShadowDecl) {
+    const auto Loc = SourceMgr.getExpansionLoc(R.ShadowDecl->getLocation());
+    if (SourceMgr.isWrittenInMainFile(Loc))
+      return true;
+  }
+  return false;
+}
+
 static SymbolQualitySignals::SymbolCategory categorize(const NamedDecl &ND) {
   class Switch
       : public ConstDeclVisitor<Switch, SymbolQualitySignals::SymbolCategory> {
@@ -231,8 +242,10 @@
     // We boost things that have decls in the main file. We give a fixed score
     // for all other declarations in sema as they are already included in the
     // translation unit.
-    float DeclProximity =
-        hasDeclInMainFile(*SemaCCResult.Declaration) ? 1.0 : 0.6;
+    float DeclProximity = (hasDeclInMainFile(*SemaCCResult.Declaration) ||
+                           hasUsingDeclInMainFile(SemaCCResult))
+                              ? 1.0
+                              : 0.6;
     SemaProximityScore = std::max(DeclProximity, SemaProximityScore);
   }
 
Index: unittests/clangd/QualityTests.cpp
===================================================================
--- unittests/clangd/QualityTests.cpp
+++ unittests/clangd/QualityTests.cpp
@@ -77,18 +77,31 @@
 TEST(QualityTests, SymbolRelevanceSignalExtraction) {
   TestTU Test;
   Test.HeaderCode = R"cpp(
-    int header();
-    int header_main();
-    )cpp";
+  int header();
+  int header_main();
+
+  namespace hdr { class Bar {}; } // namespace hdr
+
+  #define DEFINE_FLAG(X) \
+  namespace flags { \
+  int FLAGS_##X; \
+  } \
+
+  DEFINE_FLAG(FOO)
+  )cpp";
   Test.Code = R"cpp(
-    int ::header_main() {}
-    int main();
+  using hdr::Bar;
 
-    [[deprecated]]
-    int deprecated() { return 0; }
+  using flags::FLAGS_FOO;
+
+  int ::header_main() {}
+  int main();
 
-    namespace { struct X { void y() { int z; } }; }
-    struct S{}
+  [[deprecated]]
+  int deprecated() { return 0; }
+
+  namespace { struct X { void y() { int z; } }; }
+  struct S{}
   )cpp";
   auto AST = Test.build();
 
@@ -111,6 +124,32 @@
   EXPECT_FLOAT_EQ(Relevance.SemaProximityScore, 1.0f)
       << "Current file and header";
 
+  auto constructShadowDeclCompletionResult = [&](const std::string DeclName) {
+    auto *Shadow =
+        *dyn_cast<UsingDecl>(
+             &findAnyDecl(AST,
+                          [&](const NamedDecl &ND) {
+                            if (const UsingDecl *Using =
+                                    dyn_cast<UsingDecl>(&ND))
+                              if (Using->shadow_size() &&
+                                  Using->getQualifiedNameAsString() == DeclName)
+                                return true;
+                            return false;
+                          }))
+             ->shadow_begin();
+    CodeCompletionResult Result(Shadow->getTargetDecl(), 42);
+    Result.ShadowDecl = Shadow;
+    return Result;
+  };
+
+  Relevance = {};
+  Relevance.merge(constructShadowDeclCompletionResult("Bar"));
+  EXPECT_FLOAT_EQ(Relevance.SemaProximityScore, 1.0f)
+      << "Using declaration in main file";
+  Relevance.merge(constructShadowDeclCompletionResult("FLAGS_FOO"));
+  EXPECT_FLOAT_EQ(Relevance.SemaProximityScore, 1.0f)
+      << "Using declaration in main file";
+
   Relevance = {};
   Relevance.merge(CodeCompletionResult(&findAnyDecl(AST, "X"), 42));
   EXPECT_EQ(Relevance.Scope, SymbolRelevanceSignals::FileScope);
@@ -191,7 +230,8 @@
 }
 
 TEST(QualityTests, SortText) {
-  EXPECT_LT(sortText(std::numeric_limits<float>::infinity()), sortText(1000.2f));
+  EXPECT_LT(sortText(std::numeric_limits<float>::infinity()),
+            sortText(1000.2f));
   EXPECT_LT(sortText(1000.2f), sortText(1));
   EXPECT_LT(sortText(1), sortText(0.3f));
   EXPECT_LT(sortText(0.3f), sortText(0));