diff --git a/clang/lib/Sema/SemaExprCXX.cpp b/clang/lib/Sema/SemaExprCXX.cpp
--- a/clang/lib/Sema/SemaExprCXX.cpp
+++ b/clang/lib/Sema/SemaExprCXX.cpp
@@ -4252,12 +4252,14 @@
   case ICK_Lvalue_To_Rvalue:
   case ICK_Array_To_Pointer:
   case ICK_Function_To_Pointer:
-  case ICK_Function_Conversion:
-  case ICK_Qualification:
   case ICK_Num_Conversion_Kinds:
   case ICK_C_Only_Conversion:
   case ICK_Incompatible_Pointer_Conversion:
     llvm_unreachable("Improper second standard conversion");
+
+  case ICK_Function_Conversion:
+  case ICK_Qualification:
+    llvm_unreachable("Improper third standard conversion");
   }
 
   switch (SCS.Third) {
diff --git a/clang/lib/Sema/SemaOverload.cpp b/clang/lib/Sema/SemaOverload.cpp
--- a/clang/lib/Sema/SemaOverload.cpp
+++ b/clang/lib/Sema/SemaOverload.cpp
@@ -5339,7 +5339,6 @@
   // conversions are fine.
   switch (SCS.Second) {
   case ICK_Identity:
-  case ICK_Function_Conversion:
   case ICK_Integral_Promotion:
   case ICK_Integral_Conversion: // Narrowing conversions are checked elsewhere.
   case ICK_Zero_Queue_Conversion:
@@ -5385,6 +5384,7 @@
   case ICK_Function_To_Pointer:
     llvm_unreachable("found a first conversion kind in Second");
 
+  case ICK_Function_Conversion:
   case ICK_Qualification:
     llvm_unreachable("found a third conversion kind in Second");