From d4ed6b1083e9708de28ba6c7167a16745572c880 Mon Sep 17 00:00:00 2001
From: Geoff Romer <gromer@google.com>
Date: Mon, 26 Jul 2021 11:42:38 -0700
Subject: [PATCH] Enable some additional warnings. (#675)

---
 bazel/cc_toolchains/clang_cc_toolchain_config.bzl | 2 ++
 executable_semantics/interpreter/stack.h          | 5 +++++
 2 files changed, 7 insertions(+)

diff --git a/bazel/cc_toolchains/clang_cc_toolchain_config.bzl b/bazel/cc_toolchains/clang_cc_toolchain_config.bzl
index 4706c4e72613..702c0107d8da 100644
--- a/bazel/cc_toolchains/clang_cc_toolchain_config.bzl
+++ b/bazel/cc_toolchains/clang_cc_toolchain_config.bzl
@@ -124,6 +124,8 @@ def _impl(ctx):
                             "-Wextra",
                             "-Wthread-safety",
                             "-Wself-assign",
+                            "-Wimplicit-fallthrough",
+                            "-Wctad-maybe-unsupported",
                             # Unfortunately, LLVM isn't clean for this warning.
                             "-Wno-unused-parameter",
                             # We use partial sets of designated initializers in
diff --git a/executable_semantics/interpreter/stack.h b/executable_semantics/interpreter/stack.h
index 6be13a929aa1..e2e14117a2e3 100644
--- a/executable_semantics/interpreter/stack.h
+++ b/executable_semantics/interpreter/stack.h
@@ -72,6 +72,11 @@ struct Stack {
   std::vector<T> elements;
 };
 
+// Explicitly enable CTAD to silence warnings.
+// TODO: consider removing this (and perhaps the associated constructor).
+template <typename T>
+Stack(T x) -> Stack<T>;
+
 }  // namespace Carbon
 
 #endif  // EXECUTABLE_SEMANTICS_INTERPRETER_CONS_LIST_H_