diff --git a/lib/Sema/AnalysisBasedWarnings.cpp b/lib/Sema/AnalysisBasedWarnings.cpp
index e602ef1..01deec1 100644
--- a/lib/Sema/AnalysisBasedWarnings.cpp
+++ b/lib/Sema/AnalysisBasedWarnings.cpp
@@ -748,6 +748,8 @@
     if (!uses)
       return;
     
+    // FIXME: This iteration order, and thus the resulting diagnostic order,
+    //        is nondeterministic.
     for (UsesMap::iterator i = uses->begin(), e = uses->end(); i != e; ++i) {
       const VarDecl *vd = i->first;
       const UsesMap::mapped_type &V = i->second;