Change semantic of RecordContext::stealRecordChain to concatenate the chains

Author: daniel-grumberg

clang/include/clang/ExtractAPI/API.h

@@ -321,6 +321,8 @@ class RecordContext {
 
   RecordContext(APIRecord::RecordKind Kind) : Kind(Kind) {}
 
+  /// Append \p Other children chain into ours and empty out Other's record
+  /// chain.
   void stealRecordChain(RecordContext &Other);
 
   APIRecord::RecordKind getKind() const { return Kind; }

clang/lib/ExtractAPI/API.cpp

@@ -55,8 +55,15 @@ RecordContext *APIRecord::castToRecordContext(const APIRecord *Record) {
 }
 
 void RecordContext::stealRecordChain(RecordContext &Other) {
-  First = Other.First;
+  // If we don't have an empty chain append Other's chain into ours.
+  if (First)
+    Last->NextInContext = Other.First;
+  else
+    First = Other.First;
+
   Last = Other.Last;
+
+  // Delete Other's chain to ensure we don't accidentally traverse it.
   Other.First = nullptr;
   Other.Last = nullptr;
 }