diff --git a/clang/lib/AST/ExternalASTMerger.cpp b/clang/lib/AST/ExternalASTMerger.cpp
index 2761eb4..2d4d018 100644
--- a/clang/lib/AST/ExternalASTMerger.cpp
+++ b/clang/lib/AST/ExternalASTMerger.cpp
@@ -178,6 +178,7 @@
                 IP.Forward->Import(const_cast<Decl *>(SourceDecl));
             assert(ImportedDecl->getDeclContext() == DC);
             (void)ImportedDecl;
+            (void)DC;
           }
         }
       });