Add method to ignore invisible AST nodes

Reviewers: aaron.ballman

Subscribers: mgorny, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D70613
diff --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp
index da279fa..a09b1aca 100644
--- a/clang/lib/AST/ASTContext.cpp
+++ b/clang/lib/AST/ASTContext.cpp
@@ -112,6 +112,8 @@
     return E;
   case ast_type_traits::TK_IgnoreImplicitCastsAndParentheses:
     return E->IgnoreParenImpCasts();
+  case ast_type_traits::TK_IgnoreUnlessSpelledInSource:
+    return E->IgnoreUnlessSpelledInSource();
   }
   llvm_unreachable("Invalid Traversal type!");
 }