From 4bc30b7ba2c21d380bdc84baf2ebb98f6e055906 Mon Sep 17 00:00:00 2001
From: Zhaoming Jiang <zhaoming.jiang@intel.com>
Date: Fri, 1 Apr 2022 11:12:36 +0000
Subject: [PATCH] Fix default case must at last assertion in Switch()

Fix an assertion in SwitchCases that default case must be last in Switch().

Change-Id: I5ece5a20e22f8df607581373d1f0bb0bd44fb58b
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/85461
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
Commit-Queue: Zhaoming Jiang <zhaoming.jiang@intel.com>
---
 src/tint/castable.h | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/tint/castable.h b/src/tint/castable.h
index 05144f79e3..f5d2cb2c6d 100644
--- a/src/tint/castable.h
+++ b/src/tint/castable.h
@@ -641,8 +641,9 @@ inline void SwitchCases(T* object,
                         std::tuple<CASES...>&& cases) {
   using Cases = std::tuple<CASES...>;
   static constexpr int kDefaultIndex = detail::IndexOfDefaultCase<Cases>();
-  static_assert(kDefaultIndex == -1 || std::tuple_size_v<Cases> - 1,
-                "Default case must be last in Switch()");
+  static_assert(
+      kDefaultIndex == -1 || kDefaultIndex == std::tuple_size_v<Cases> - 1,
+      "Default case must be last in Switch()");
   static constexpr bool kHasDefaultCase = kDefaultIndex >= 0;
   static constexpr bool kHasReturnType = !std::is_same_v<RETURN_TYPE, void>;