diff --git a/lib/Sema/SemaExprCXX.cpp b/lib/Sema/SemaExprCXX.cpp
index c96ab42..f1cb5ea 100644
--- a/lib/Sema/SemaExprCXX.cpp
+++ b/lib/Sema/SemaExprCXX.cpp
@@ -2129,6 +2129,7 @@
       FunctionDecl *FD = ICS.UserDefined.ConversionFunction;
       CastKind CastKind;
       QualType BeforeToType;
+      assert(FD && "FIXME: aggregate initialization from init list");
       if (const CXXConversionDecl *Conv = dyn_cast<CXXConversionDecl>(FD)) {
         CastKind = CK_UserDefinedConversion;