fix: track whether base-specifiers were a pack expansion

Author: sdkrystian

src/lib/AST/ASTVisitor.cpp

@@ -1758,13 +1758,18 @@ class ASTVisitor
                         access == AccessSpecifier::AS_protected)
                         continue;
                 }
-
+                // the extraction of the base type is
+                // performed in direct dependency mode
+                auto BaseType = buildTypeInfo(
+                    B.getType(),
+                    ExtractMode::DirectDependency);
+                // CXXBaseSpecifier::getEllipsisLoc indicates whether the
+                // base was a pack expansion; a PackExpansionType is not built
+                // for base-specifiers
+                if(BaseType && B.getEllipsisLoc().isValid())
+                    BaseType->IsPackExpansion = true;
                 I.Bases.emplace_back(
-                    // the extraction of the base type is
-                    // performed in direct dependency mode
-                    buildTypeInfo(
-                        B.getType(),
-                        ExtractMode::DirectDependency),
+                    std::move(BaseType),
                     convertToAccessKind(access),
                     B.isVirtual());
             }

test-files/old-tests/record-inheritance.cpp

@@ -19,3 +19,6 @@ class C6 : virtual C1 {};
 class C7 : public C5, public C6 {};
 
 struct S5 : private S0, protected S1 {};
+
+template<typename... Ts>
+struct S6 : Ts... { };

test-files/old-tests/record-inheritance.xml

@@ -90,5 +90,14 @@
       <type id="Tu+ql/Sdpk31DKHwwD/67uI3OZE=" name="S1"/>
     </base>
   </struct>
+  <template>
+    <tparam name="Ts" class="type"/>
+    <struct name="S6" id="dt7vZMcsOL5ylokCpCZgvCsG/po=">
+      <file path="record-inheritance.cpp" line="24" class="def"/>
+      <base>
+        <type is-pack="1" name="Ts"/>
+      </base>
+    </struct>
+  </template>
 </namespace>
 </mrdocs>