diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index 18636a4..51b5449 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -4439,6 +4439,7 @@
   // FIXME: This implementation is an ugly hack!
   if (PrevDecl) {
     PrevDecl->addAttr(::new (Context) AliasAttr(AliasName->getName()));
+    PrevDecl->addAttr(::new (Context) WeakAttr());
     return;
   }
   Diag(PragmaLoc, diag::err_unsupported_pragma_weak);