diff --git a/lib/Basic/LangOptions.cpp b/lib/Basic/LangOptions.cpp
index e18d925..f8714b2 100644
--- a/lib/Basic/LangOptions.cpp
+++ b/lib/Basic/LangOptions.cpp
@@ -31,6 +31,8 @@
   Name = Default;
 #include "clang/Basic/LangOptions.def"
 
+  // FIXME: This should not be reset; modules can be different with different
+  // sanitizer options (this affects __has_feature(address_sanitizer) etc).
   Sanitize = SanitizerOptions::Disabled;
 
   CurrentModule.clear();