treat unused parameter as error (#1608)

---------

Signed-off-by: romintomasetti <romin.tomasetti@gmail.com>
Co-authored-by: Eric Niebler <eniebler@nvidia.com>

Author: romintomasetti

CMakeLists.txt

@@ -226,7 +226,7 @@ add_library(stdexec_executable_flags INTERFACE)
 
 # Enable warnings
 target_compile_options(stdexec_executable_flags INTERFACE
-                       $<$<STREQUAL:${stdexec_compiler_frontend},GNU>:-Wall>
+                       $<$<STREQUAL:${stdexec_compiler_frontend},GNU>:-Wall;-Werror=unused-parameter>
                        $<$<STREQUAL:${stdexec_compiler_frontend},AppleClang>:-Wall>
                        $<$<STREQUAL:${stdexec_compiler_frontend},MSVC>:/W4>)
 

examples/nvexec/launch.cpp

@@ -49,7 +49,7 @@ auto main() -> int {
   auto snd = stdexec::transfer_just(stream.get_scheduler(), first, last)
            | nvexec::launch(
                {.grid_size = NUM_BLOCKS, .block_size = THREAD_BLOCK_SIZE},
-               [](cudaStream_t stm, int* first, int* last) {
+               [](cudaStream_t, int* first, int* last) {
                  assert(nvexec::is_on_gpu());
                  int32_t idx = blockIdx.x * blockDim.x + threadIdx.x;
                  if (idx < (last - first)) {

examples/nvexec/maxwell/common.cuh

@@ -366,7 +366,7 @@ class result_dumper_t {
     , accessor_(accessor) {
   }
 
-  void operator()(bool update_time = true) const {
+  void operator()([[maybe_unused]] bool update_time = true) const {
     int rank_ = 0;
     const std::string filename = std::string("output_") + std::to_string(rank_) + "_"
                                + std::to_string(0) + ".vtk";

examples/nvexec/maxwell/stdpar.cuh

@@ -32,7 +32,7 @@
 #include <thrust/iterator/counting_iterator.h>
 
 template <class Policy>
-auto is_gpu_policy(Policy&& policy) -> bool {
+auto is_gpu_policy([[maybe_unused]] Policy&& policy) -> bool {
 #if defined(_NVHPC_CUDA) || defined(__CUDACC__)
   bool* flag{};
   STDEXEC_TRY_CUDA_API(cudaMallocHost(&flag, sizeof(bool)));

include/exec/start_now.hpp

@@ -89,7 +89,7 @@ namespace exec {
         __storage_base<_EnvId>* __stg_;
 
         template <class... _As>
-        void set_value(_As&&... __as) noexcept {
+        void set_value(_As&&...) noexcept {
           __stg_->__complete();
         }
 

include/exec/task.hpp

@@ -157,8 +157,8 @@ namespace exec {
     struct __default_awaiter_context {
       template <__scheduler_affinity _Affinity>
       explicit __default_awaiter_context(
-        __default_task_context_impl<_Affinity>& __self,
-        _ParentPromise& __parent) noexcept {
+        __default_task_context_impl<_Affinity>&,
+        _ParentPromise&) noexcept {
       }
     };
 
@@ -225,8 +225,8 @@ namespace exec {
     struct __default_awaiter_context<void> {
       template <__scheduler_affinity _Affinity, class _ParentPromise>
       explicit __default_awaiter_context(
-        __default_task_context_impl<_Affinity>& __self,
-        _ParentPromise& __parent) noexcept {
+        __default_task_context_impl<_Affinity>&,
+        _ParentPromise&) noexcept {
       }
 
       template <__scheduler_affinity _Affinity, __indirect_stop_token_provider _ParentPromise>

include/nvexec/detail/memory.cuh

@@ -314,7 +314,7 @@ namespace nvexec::_strm {
       , live_blocks(ptr_comparator_t{}) {
     }
 
-    auto do_allocate(const std::size_t bytes, const std::size_t alignment) -> void* override {
+    auto do_allocate(const std::size_t bytes, [[maybe_unused]]const std::size_t alignment) -> void* override {
       assert(alignment <= block_alignment);
 
       std::lock_guard<std::mutex> lock(mutex);

include/nvexec/detail/queue.cuh

@@ -68,8 +68,7 @@ namespace nvexec::_strm::queue {
 
   struct root_task_t : task_base_t {
     root_task_t() {
-      this->execute_ = [](task_base_t* t) noexcept {
-      };
+      this->execute_ = [](task_base_t*) noexcept {};
       this->free_ = [](task_base_t* t) noexcept {
         STDEXEC_ASSERT_CUDA_API(cudaFree(static_cast<void*>(t->atom_next_)));
       };

include/nvexec/detail/throw_on_cuda_error.cuh

@@ -65,7 +65,7 @@ namespace nvexec::detail {
   }
 
   [[nodiscard]]
-  inline auto log_on_cuda_error(cudaError_t status, char const * file_name, int line) noexcept
+  inline auto log_on_cuda_error(cudaError_t status, [[maybe_unused]] char const *const file_name, [[maybe_unused]] const int line) noexcept
     -> ::cudaError_t {
     // Clear the global CUDA error state which may have been set by the last
     // call. Otherwise, errors may "leak" to unrelated calls.

include/stdexec/__detail/__submit.hpp

@@ -135,7 +135,7 @@ namespace stdexec {
       : __result_(connect(static_cast<_Sender&&>(__sndr), static_cast<_Receiver&&>(__rcvr))) {
     }
 
-    void submit(_Sender&& __sndr, _Receiver&&) noexcept {
+    void submit(_Sender&&, _Receiver&&) noexcept {
       stdexec::start(__result_);
     }