diff --git a/clang/lib/AST/ASTDumper.cpp b/clang/lib/AST/ASTDumper.cpp
index 6b4a078734c0..4da6240f8670 100644
--- a/clang/lib/AST/ASTDumper.cpp
+++ b/clang/lib/AST/ASTDumper.cpp
@@ -981,6 +981,10 @@ void ASTDumper::dumpDecl(const Decl *D) {
       OS << " in " << M->getFullModuleName();
     else if (Module *M = D->getLocalOwningModule())
       OS << " in (local) " << M->getFullModuleName();
+    if (auto *ND = dyn_cast<NamedDecl>(D))
+      for (Module *M : D->getASTContext().getModulesWithMergedDefinition(
+               const_cast<NamedDecl *>(ND)))
+        dumpChild([=] { OS << "also in " << M->getFullModuleName(); });
     if (const NamedDecl *ND = dyn_cast<NamedDecl>(D))
       if (ND->isHidden())
         OS << " hidden";