If a template instantation introduces a name into a namespace, we need to write

out a visible update record for that namespace even if it was never declared in
this module.

llvm-svn: 204554

1 files changed, 12 insertions, 0 deletions

diff --git a/clang/lib/Serialization/ASTWriterDecl.cpp b/clang/lib/Serialization/ASTWriterDecl.cpp
index d83b3ede38e..3aeb89559e7 100644
--- a/clang/lib/Serialization/ASTWriterDecl.cpp
+++ b/clang/lib/Serialization/ASTWriterDecl.cpp
@@ -176,6 +176,18 @@ void ASTDeclWriter::VisitDecl(Decl *D) {
   Record.push_back(D->getAccess());
   Record.push_back(D->isModulePrivate());
   Record.push_back(Writer.inferSubmoduleIDFromLocation(D->getLocation()));
+
+  // If this declaration injected a name into a context different from its
+  // lexical context, and that context is an imported namespace, we need to
+  // update its visible declarations to include this name.
+  //
+  // This happens when we instantiate a class with a friend declaration or a
+  // function with a local extern declaration, for instance.
+  if (D->isOutOfLine()) {
+    auto *NS = dyn_cast<NamespaceDecl>(D->getDeclContext()->getRedeclContext());
+    if (NS && NS->isFromASTFile())
+      Writer.AddUpdatedDeclContext(NS);
+  }
 }
 
 void ASTDeclWriter::VisitTranslationUnitDecl(TranslationUnitDecl *D) {