diff --git a/llvm/unittests/DebugInfo/PDB/PDBApiTest.cpp b/llvm/unittests/DebugInfo/PDB/PDBApiTest.cpp
index 569fc14..f70fca7 100644
--- a/llvm/unittests/DebugInfo/PDB/PDBApiTest.cpp
+++ b/llvm/unittests/DebugInfo/PDB/PDBApiTest.cpp
@@ -11,6 +11,7 @@
 
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/DebugInfo/PDB/IPDBEnumChildren.h"
+#include "llvm/DebugInfo/PDB/IPDBLineNumber.h"
 #include "llvm/DebugInfo/PDB/IPDBRawSymbol.h"
 #include "llvm/DebugInfo/PDB/IPDBSession.h"
 #include "llvm/DebugInfo/PDB/IPDBSourceFile.h"
@@ -195,6 +196,10 @@
     return {};
   }
 
+  std::unique_ptr<IPDBLineNumber> getSrcLineOnTypeDefn() const override {
+    return nullptr;
+  }
+
   MOCK_SYMBOL_ACCESSOR(getAccess)
   MOCK_SYMBOL_ACCESSOR(getAddressOffset)
   MOCK_SYMBOL_ACCESSOR(getAddressSection)