Tweak availability checking to look through typedef declarations.

llvm-svn: 237396

1 files changed, 18 insertions, 2 deletions

diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index 8dee0eebc51..0c5c23a3e2a 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -104,13 +104,29 @@ DiagnoseAvailabilityOfDecl(Sema &S, NamedDecl *D, SourceLocation Loc,
                            bool ObjCPropertyAccess) {
   // See if this declaration is unavailable or deprecated.
   std::string Message;
+  AvailabilityResult Result = D->getAvailability(&Message);
+
+  // For typedefs, if the typedef declaration appears available look
+  // to the underlying type to see if it is more restrictive.
+  while (const TypedefNameDecl *TD = TD = dyn_cast<TypedefNameDecl>(D)) {
+    if (Result == AR_Available) {
+      if (const TagType *TT = TD->getUnderlyingType()->getAs<TagType>()) {
+        D = TT->getDecl();
+        Result = D->getAvailability(&Message);
+        continue;
+      }
+    }
+    break;
+  }
     
   // Forward class declarations get their attributes from their definition.
   if (ObjCInterfaceDecl *IDecl = dyn_cast<ObjCInterfaceDecl>(D)) {
-    if (IDecl->getDefinition())
+    if (IDecl->getDefinition()) {
       D = IDecl->getDefinition();
+      Result = D->getAvailability(&Message);
+    }
   }
-  AvailabilityResult Result = D->getAvailability(&Message);
+
   if (const EnumConstantDecl *ECD = dyn_cast<EnumConstantDecl>(D))
     if (Result == AR_Available) {
       const DeclContext *DC = ECD->getDeclContext();