[nostalgia/geo] Fix Vec2 test

src/nostalgia/geo/vec.hpp

@@ -9,6 +9,7 @@
 #endif
 
 #include <ox/model/def.hpp>
+#include <ox/std/assert.hpp>
 #include <ox/std/bit.hpp>
 #include <ox/std/def.hpp>
 #include <ox/std/error.hpp>
@@ -192,11 +193,35 @@ struct Vec {
 		}
 
 		constexpr auto &operator[](std::size_t i) noexcept {
-			return start()[i];
+			if (std::is_constant_evaluated()) {
+				switch (i) {
+					case 0:
+						return x;
+					case 1:
+						return y;
+					default:
+						oxAssert(false, "Read past end of Vec2");
+						return y;
+				}
+			} else {
+				return start()[i];
+			}
 		}
 
 		constexpr const auto &operator[](std::size_t i) const noexcept {
-			return start()[i];
+			if (std::is_constant_evaluated()) {
+				switch (i) {
+					case 0:
+						return x;
+					case 1:
+						return y;
+					default:
+						oxAssert(false, "Read past end of Vec2");
+						return y;
+				}
+			} else {
+				return start()[i];
+			}
 		}
 
 		constexpr auto operator==(const Vec &v) const noexcept {