[Modules TS] Diagnose 'export' declaration within 'export' declaration.

llvm-svn: 282443

1 files changed, 16 insertions, 0 deletions

diff --git a/clang/lib/AST/DeclBase.cpp b/clang/lib/AST/DeclBase.cpp
index cea511b5118..77e74b044fd 100644
--- a/clang/lib/AST/DeclBase.cpp
+++ b/clang/lib/AST/DeclBase.cpp
@@ -377,6 +377,22 @@ bool Decl::isReferenced() const {
   return false; 
 }
 
+bool Decl::isExported() const {
+  if (isModulePrivate())
+    return false;
+  // Namespaces are always exported.
+  if (isa<TranslationUnitDecl>(this) || isa<NamespaceDecl>(this))
+    return true;
+  // Otherwise, this is a strictly lexical check.
+  for (auto *DC = getLexicalDeclContext(); DC; DC = DC->getLexicalParent()) {
+    if (cast<Decl>(DC)->isModulePrivate())
+      return false;
+    if (isa<ExportDecl>(DC))
+      return true;
+  }
+  return false;
+}
+
 bool Decl::hasDefiningAttr() const {
   return hasAttr<AliasAttr>() || hasAttr<IFuncAttr>();
 }