PR13527: don't assert if a function is explicitly defaulted when it's already
been defined.

llvm-svn: 161315
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index eb5b0cd..c1086fb 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -7483,6 +7483,7 @@
     else
       Diag(FD->getLocation(), diag::err_redefinition) << FD->getDeclName();
     Diag(Definition->getLocation(), diag::note_previous_definition);
+    FD->setInvalidDecl();
   }
 }