[change-namespace] always add a '::' prefix when a symbol reference needs to be fully-qualified.

2 files changed, 8 insertions, 1 deletions

diff --git a/clang-tools-extra/change-namespace/ChangeNamespace.cpp b/clang-tools-extra/change-namespace/ChangeNamespace.cpp
index 45064ebeeb7..2dca1a98893 100644
--- a/clang-tools-extra/change-namespace/ChangeNamespace.cpp
+++ b/clang-tools-extra/change-namespace/ChangeNamespace.cpp
@@ -663,6 +663,10 @@ void ChangeNamespaceTool::replaceQualifiedSymbolInDeclContext(
   // old namespace, we don't create replacement.
   if (NestedName == ReplaceName)
     return;
+  // If the reference need to be fully-qualified, add a leading "::" unless
+  // NewNamespace is the global namespace.
+  if (ReplaceName == FromDeclName && !NewNamespace.empty())
+    ReplaceName = "::" + ReplaceName;
   auto R = createReplacement(Start, End, ReplaceName, *Result.SourceManager);
   auto Err = FileToReplacements[R.getFilePath()].add(R);
   if (Err)
diff --git a/clang-tools-extra/change-namespace/ChangeNamespace.h b/clang-tools-extra/change-namespace/ChangeNamespace.h
index 048c32fd2d3..342457adf4c 100644
--- a/clang-tools-extra/change-namespace/ChangeNamespace.h
+++ b/clang-tools-extra/change-namespace/ChangeNamespace.h
@@ -24,6 +24,9 @@ namespace change_namespace {
 // namespaces while references to symbols (e.g. types, functions) which are not
 // defined in the changed namespace will be correctly qualified by prepending
 // namespace specifiers before them.
+// This will try to add shortest namespace specifiers possible. When a symbol
+// reference needs to be fully-qualified, this adds a "::" prefix to the
+// namespace specifiers unless the new namespace is the global namespace.
 // For classes, only classes that are declared/defined in the given namespace in
 // speficifed files will be moved: forward declarations will remain in the old
 // namespace.
@@ -38,7 +41,7 @@ namespace change_namespace {
 //   class FWD;
 //   }  // a
 //   namespace x {
-//   class A { a::FWD *fwd; }
+//   class A { ::a::FWD *fwd; }
 //   }  // x
 // FIXME: support moving typedef, enums across namespaces.
 class ChangeNamespaceTool : public ast_matchers::MatchFinder::MatchCallback {