Index: clang/lib/AST/Type.cpp
===================================================================
--- clang/lib/AST/Type.cpp
+++ clang/lib/AST/Type.cpp
@@ -3320,8 +3320,9 @@
   switch (getExceptionSpecType()) {
   case EST_Unparsed:
   case EST_Unevaluated:
-  case EST_Uninstantiated:
     llvm_unreachable("should not call this with unresolved exception specs");
+  case EST_Uninstantiated:
+    return CT_Dependent;
 
   case EST_DynamicNone:
   case EST_BasicNoexcept: