diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index 3054088bd6d8..b0b362f4cdb5 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -2980,10 +2980,15 @@ Sema::BuildMemInitializer(Decl *ConstructorD,
     if (BaseType.isNull()) {
       BaseType = Context.getTypeDeclType(TyD);
       MarkAnyDeclReferenced(TyD->getLocation(), TyD, /*OdrUse=*/false);
-      if (SS.isSet())
-        // FIXME: preserve source range information
+      if (SS.isSet()) {
         BaseType = Context.getElaboratedType(ETK_None, SS.getScopeRep(),
                                              BaseType);
+        TInfo = Context.CreateTypeSourceInfo(BaseType);
+        ElaboratedTypeLoc TL = TInfo->getTypeLoc().castAs<ElaboratedTypeLoc>();
+        TL.getNamedTypeLoc().castAs<TypeSpecTypeLoc>().setNameLoc(IdLoc);
+        TL.setElaboratedKeywordLoc(SourceLocation());
+        TL.setQualifierLoc(SS.getWithLocInContext(Context));
+      }
     }
   }
 
diff --git a/clang/test/Index/namespaced-base-ctor-init.cpp b/clang/test/Index/namespaced-base-ctor-init.cpp
new file mode 100644
index 000000000000..2d60f7c6530a
--- /dev/null
+++ b/clang/test/Index/namespaced-base-ctor-init.cpp
@@ -0,0 +1,10 @@
+namespace ns1 {
+struct Base {};
+struct Derived : Base {
+  Derived() : ns1::Base() {}
+};
+}
+
+// RUN: c-index-test -test-load-source all %s | FileCheck %s
+// CHECK: namespaced-base-ctor-init.cpp:4:15: NamespaceRef=ns1:1:11 Extent=[4:15 - 4:18]
+// CHECK: namespaced-base-ctor-init.cpp:4:20: TypeRef=struct ns1::Base:2:8 Extent=[4:20 - 4:24]