From b429a17545be8418f8d5887ad302c9b8af031177 Mon Sep 17 00:00:00 2001
From: Peter Bell <peterbell10@live.co.uk>
Date: Thu, 25 Aug 2022 23:43:25 +0100
Subject: [PATCH] Enable -Wunused-local-typedefs (#83708)

I recently had a PR reverted because it triggered an
unused-local-typedefs warning, so disabling these in the CMake build
is counter-productive.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/83708
Approved by: https://github.com/albanD
---
 cmake/public/utils.cmake                |  1 -
 test/cpp/api/CMakeLists.txt             |  1 -
 torch/CMakeLists.txt                    |  2 --
 torch/csrc/api/include/torch/nn/pimpl.h | 10 +++++++++-
 4 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/cmake/public/utils.cmake b/cmake/public/utils.cmake
index e9152ab76449a5..b0c4cc6f08b56d 100644
--- a/cmake/public/utils.cmake
+++ b/cmake/public/utils.cmake
@@ -451,7 +451,6 @@ function(torch_compile_options libname)
         -Wno-unused-parameter
         -Wno-unused-function
         -Wno-unused-result
-        -Wno-unused-local-typedefs
         -Wno-missing-field-initializers
         -Wno-write-strings
         -Wno-unknown-pragmas
diff --git a/test/cpp/api/CMakeLists.txt b/test/cpp/api/CMakeLists.txt
index 1e205f56b4f14d..f1e1765af5de76 100644
--- a/test/cpp/api/CMakeLists.txt
+++ b/test/cpp/api/CMakeLists.txt
@@ -55,7 +55,6 @@ target_include_directories(test_api PRIVATE ${ATen_CPU_INCLUDE})
 target_link_libraries(test_api PRIVATE torch gtest)
 if(NOT MSVC)
   target_compile_options_if_supported(test_api -Wno-unused-variable)
-  target_compile_options_if_supported(test_api -Wno-unused-local-typedefs)
 endif()
 
 if(USE_CUDA)
diff --git a/torch/CMakeLists.txt b/torch/CMakeLists.txt
index 1859d42365af71..7586745602fd01 100644
--- a/torch/CMakeLists.txt
+++ b/torch/CMakeLists.txt
@@ -286,7 +286,6 @@ if(USE_DEPLOY)
   add_library(torch_python_obj OBJECT ${TORCH_PYTHON_SRCS})
   if(NOT MSVC)
     target_compile_options(torch_python_obj PRIVATE -Wno-unused-variable)
-    target_compile_options(torch_python_obj PRIVATE -Wno-unused-local-typedefs)
   endif()
   if(USE_DISTRIBUTED)
     # Set c10d-related compile definitions. For a "normal" build of
@@ -401,7 +400,6 @@ endif()
 
 if(NOT MSVC)
   target_compile_options(torch_python PRIVATE -Wno-unused-variable)
-  target_compile_options(torch_python PRIVATE -Wno-unused-local-typedefs)
 endif()
 
 # Required workaround for generated sources
diff --git a/torch/csrc/api/include/torch/nn/pimpl.h b/torch/csrc/api/include/torch/nn/pimpl.h
index b3a2f2fd28c6d8..d66d83c257ebd0 100644
--- a/torch/csrc/api/include/torch/nn/pimpl.h
+++ b/torch/csrc/api/include/torch/nn/pimpl.h
@@ -191,6 +191,14 @@ serialize::InputArchive& operator>>(
 } // namespace nn
 } // namespace torch
 
+// Workaround for CUDA 10.2 and below not allowing attribute unused on
+// using declarations.
+#ifdef __CUDACC__
+#define TORCH_UNUSED_EXCEPT_CUDA
+#else
+#define TORCH_UNUSED_EXCEPT_CUDA C10_UNUSED
+#endif
+
 /// Defines a class `Name` which inherits from `nn::ModuleHolder` to provide a
 /// wrapper over a `std::shared_ptr<ImplType>`.
 /// `Impl` is a type alias for `ImplType` which provides a way to call static
@@ -199,7 +207,7 @@ serialize::InputArchive& operator>>(
   class Name : public torch::nn::ModuleHolder<ImplType> { /* NOLINT */ \
    public:                                                             \
     using torch::nn::ModuleHolder<ImplType>::ModuleHolder;             \
-    using Impl = ImplType;                                             \
+    using Impl TORCH_UNUSED_EXCEPT_CUDA = ImplType;                    \
   }
 
 /// Like `TORCH_MODULE_IMPL`, but defaults the `ImplType` name to `<Name>Impl`.