diff --git a/src/google/protobuf/descriptor.cc b/src/google/protobuf/descriptor.cc
index 9e3a49d7bf..efcd86e358 100644
--- a/src/google/protobuf/descriptor.cc
+++ b/src/google/protobuf/descriptor.cc
@@ -5375,6 +5375,7 @@ struct IncrementWhenDestroyed {
 
 }  // namespace
 
+
 void DescriptorBuilder::BuildMessage(const DescriptorProto& proto,
                                      const Descriptor* parent,
                                      Descriptor* result,
diff --git a/src/google/protobuf/descriptor.h b/src/google/protobuf/descriptor.h
index f6359e845c..22bc03c745 100644
--- a/src/google/protobuf/descriptor.h
+++ b/src/google/protobuf/descriptor.h
@@ -65,6 +65,7 @@
 #include "google/protobuf/port.h"
 #include "absl/base/attributes.h"
 #include "absl/base/call_once.h"
+#include "absl/container/btree_map.h"
 #include "absl/container/flat_hash_map.h"
 #include "absl/log/absl_check.h"
 #include "absl/log/absl_log.h"
@@ -1902,7 +1903,7 @@ class PROTOBUF_EXPORT DescriptorPool {
     // in a .proto file.
     enum ErrorLocation {
       NAME,           // the symbol name, or the package name for files
-      NUMBER,         // field or extension range number
+      NUMBER,         // field, extension range or extension decl number
       TYPE,           // field type
       EXTENDEE,       // field extendee
       DEFAULT_VALUE,  // field default value
diff --git a/src/google/protobuf/descriptor_unittest.cc b/src/google/protobuf/descriptor_unittest.cc
index 80eebfec84..64e6b2c52a 100644
--- a/src/google/protobuf/descriptor_unittest.cc
+++ b/src/google/protobuf/descriptor_unittest.cc
@@ -3979,6 +3979,16 @@ class ValidationErrorTest : public testing::Test {
     BuildFileInTestPool(DescriptorProto::descriptor()->file());
   }
 
+  void BuildDescriptorMessagesInTestPoolWithErrors(
+      absl::string_view expected_errors) {
+    FileDescriptorProto file_proto;
+    DescriptorProto::descriptor()->file()->CopyTo(&file_proto);
+    MockErrorCollector error_collector;
+    EXPECT_TRUE(pool_.BuildFileCollectingErrors(file_proto, &error_collector) ==
+                nullptr);
+    EXPECT_EQ(error_collector.text_, expected_errors);
+  }
+
   DescriptorPool pool_;
 };