From 846441f210dc12fa38bc7dbb87558e6a54b71a89 Mon Sep 17 00:00:00 2001
From: Ben Deane <ben@elbeno.com>
Date: Fri, 26 Sep 2025 22:04:11 -0600
Subject: [PATCH] :rotating_light: Fix warnings arising from `-Wnrvo`

Problem:
- CIB is not warning free with respect to -Wnrvo.

Solution:
- Add some trailing return types etc to fix warnings.
---
 include/log/catalog/mipi_builder.hpp  |  3 ++-
 include/lookup/pseudo_pext_lookup.hpp | 15 ++++++++++-----
 include/lookup/strategies.hpp         | 26 +++++++++++++++-----------
 include/match/and.hpp                 |  4 ++--
 include/match/or.hpp                  |  4 ++--
 5 files changed, 31 insertions(+), 21 deletions(-)

diff --git a/include/log/catalog/mipi_builder.hpp b/include/log/catalog/mipi_builder.hpp
index bacbea00..da88ffe0 100644
--- a/include/log/catalog/mipi_builder.hpp
+++ b/include/log/catalog/mipi_builder.hpp
@@ -32,7 +32,8 @@ template <packer P> struct builder<defn::short32_msg_t, P> {
 
 template <typename Storage, packer P> struct catalog_builder {
     template <auto Level, packable... Ts>
-    static auto build(string_id id, module_id m, unit_t u, Ts... args) {
+    static auto build(string_id id, module_id m, unit_t u, Ts... args)
+        -> defn::catalog_msg_t::owner_t<Storage> {
         using namespace msg;
         defn::catalog_msg_t::owner_t<Storage> message{
             "severity"_field = Level, "module_id"_field = m, "unit"_field = u};
diff --git a/include/lookup/pseudo_pext_lookup.hpp b/include/lookup/pseudo_pext_lookup.hpp
index a660eb6f..5af448b8 100644
--- a/include/lookup/pseudo_pext_lookup.hpp
+++ b/include/lookup/pseudo_pext_lookup.hpp
@@ -170,7 +170,8 @@ constexpr auto with_mask(T const mask, std::array<T, S> const &keys)
 }
 
 template <typename T, typename V, std::size_t S>
-constexpr auto get_keys(std::array<entry<T, V>, S> const &entries) {
+constexpr auto get_keys(std::array<entry<T, V>, S> const &entries)
+    -> std::array<detail::raw_integral_t<T>, S> {
     using raw_t = detail::raw_integral_t<T>;
     std::array<raw_t, S> new_keys{};
 
@@ -373,7 +374,8 @@ struct pseudo_pext_lookup {
             return empty_impl<key_type, value_type, default_value>{};
 
         } else if constexpr (use_indirect_strategy) {
-            constexpr auto storage = [&]() {
+            constexpr auto storage =
+                [&]() -> std::remove_const_t<decltype(input.entries)> {
                 auto s = input.entries;
 
                 // sort by the hashed key to group all the buckets together
@@ -416,8 +418,9 @@ struct pseudo_pext_lookup {
                 return s;
             }();
 
-            constexpr auto lookup_table = [&]() {
-                using lookup_idx_t = detail::uint_for_<storage.size()>;
+            using lookup_idx_t = detail::uint_for_<storage.size()>;
+            constexpr auto lookup_table =
+                [&]() -> std::array<lookup_idx_t, lookup_table_size> {
                 std::array<lookup_idx_t, lookup_table_size> t{};
 
                 t.fill(0);
@@ -442,7 +445,9 @@ struct pseudo_pext_lookup {
                 p, lookup_table, storage};
 
         } else {
-            constexpr auto storage = [&]() {
+            constexpr auto storage =
+                [&]() -> std::array<entry<raw_key_type, value_type>,
+                                    lookup_table_size> {
                 std::array<entry<raw_key_type, value_type>, lookup_table_size>
                     s{};
 
diff --git a/include/lookup/strategies.hpp b/include/lookup/strategies.hpp
index b4b42b5c..34410dbb 100644
--- a/include/lookup/strategies.hpp
+++ b/include/lookup/strategies.hpp
@@ -4,26 +4,30 @@
 #include <lookup/strategy_failed.hpp>
 
 #include <stdx/compiler.hpp>
+#include <stdx/type_traits.hpp>
 
-namespace lookup {
-template <typename...> struct strategies;
+#include <algorithm>
+#include <array>
+#include <iterator>
 
-template <> struct strategies<> {
+namespace lookup {
+struct fail_strategy_t {
     [[nodiscard]] CONSTEVAL static auto make(compile_time auto)
         -> strategy_failed_t {
         return {};
     }
 };
 
-template <typename T, typename... Ts> struct strategies<T, Ts...> {
+template <typename... Ts> struct strategies {
     [[nodiscard]] CONSTEVAL static auto make(compile_time auto input) {
-        constexpr auto candidate = T::make(input);
-
-        if constexpr (strategy_failed(candidate)) {
-            return strategies<Ts...>::make(input);
-        } else {
-            return candidate;
-        }
+        constexpr auto idx = [&] {
+            constexpr auto results =
+                std::array{not strategy_failed(Ts::make(input))...};
+            return std::distance(
+                std::cbegin(results),
+                std::find(std::cbegin(results), std::cend(results), true));
+        }();
+        return stdx::nth_t<idx, Ts..., fail_strategy_t>::make(input);
     }
 };
 } // namespace lookup
diff --git a/include/match/and.hpp b/include/match/and.hpp
index c0ac55ab..739ebf26 100644
--- a/include/match/and.hpp
+++ b/include/match/and.hpp
@@ -25,9 +25,9 @@ template <matcher L, matcher R> struct and_t : bin_op_t<and_t, "and", L, R> {
         auto r = simplify(m.rhs);
 
         if constexpr (implies(l, r)) {
-            return l;
+            return [&] { return l; }();
         } else if constexpr (implies(r, l)) {
-            return r;
+            return [&] { return r; }();
         } else if constexpr (implies(l, negate(r)) or implies(r, negate(l))) {
             return never;
         } else {
diff --git a/include/match/or.hpp b/include/match/or.hpp
index eb86413f..9ab54ed4 100644
--- a/include/match/or.hpp
+++ b/include/match/or.hpp
@@ -24,9 +24,9 @@ template <matcher L, matcher R> struct or_t : bin_op_t<or_t, "or", L, R> {
         auto r = simplify(m.rhs);
 
         if constexpr (implies(l, r)) {
-            return r;
+            return [&] { return r; }();
         } else if constexpr (implies(r, l)) {
-            return l;
+            return [&] { return l; }();
         } else if constexpr (implies(negate(l), r) or implies(negate(r), l)) {
             return always;
         } else {