From 36a90d2870248555c326b9c0d43a4c53c0a8650c Mon Sep 17 00:00:00 2001
From: Ben Deane <ben@elbeno.com>
Date: Tue, 3 Mar 2026 07:26:14 -0700
Subject: [PATCH] :art: Support `ct_capacity` for C-style arrays

Problem:
- `ct_capacity` works with `std:array` but not with C-style arrays.

Solution:
- Make it work for C-style arrays.
---
 include/stdx/iterator.hpp | 3 +++
 test/iterator.cpp         | 5 +++++
 2 files changed, 8 insertions(+)

diff --git a/include/stdx/iterator.hpp b/include/stdx/iterator.hpp
index e315343..46bd7cc 100644
--- a/include/stdx/iterator.hpp
+++ b/include/stdx/iterator.hpp
@@ -24,6 +24,9 @@ constexpr auto ct_capacity_v = detail::ct_capacity_fail<T>{};
 template <typename T, std::size_t N>
 constexpr auto ct_capacity_v<std::array<T, N>> = N;
 
+// NOLINTNEXTLINE(modernize-avoid-c-arrays)
+template <typename T, std::size_t N> constexpr auto ct_capacity_v<T[N]> = N;
+
 template <typename T> constexpr auto ct_capacity_v<T const> = ct_capacity_v<T>;
 
 template <typename T>
diff --git a/test/iterator.cpp b/test/iterator.cpp
index a20ba1e..7e37517 100644
--- a/test/iterator.cpp
+++ b/test/iterator.cpp
@@ -20,6 +20,11 @@ TEST_CASE("compile-time capacity (std::array)", "[iterator]") {
     STATIC_REQUIRE(stdx::ct_capacity(a) == 4u);
 }
 
+TEST_CASE("compile-time capacity (C-style array)", "[iterator]") {
+    int a[4]{};
+    STATIC_REQUIRE(stdx::ct_capacity(a) == 4u);
+}
+
 #if __cpp_lib_span >= 202002L
 TEST_CASE("compile-time capacity (std::span)", "[iterator]") {
     std::array a{1, 2, 3, 4};