diff --git a/rx/include/rx/StaticString.hpp b/rx/include/rx/StaticString.hpp
index 708375c2d..58474803f 100644
--- a/rx/include/rx/StaticString.hpp
+++ b/rx/include/rx/StaticString.hpp
@@ -1,10 +1,10 @@
 #pragma once
 #include "format-base.hpp"
+#include "rx/die.hpp"
 #include <cassert>
 #include <compare>
 #include <cstddef>
 #include <cstring>
-#include <stdexcept>
 #include <string_view>
 #include <type_traits>
 
@@ -111,16 +111,12 @@ public:
   }
 
   [[nodiscard]] char &at(std::size_t pos) {
-    if (pos >= m_size) {
-      throw std::out_of_range("StaticString::at: index out of range");
-    }
+    dieIf(pos >= m_size, "StaticString::at: index out of range");
     return m_data[pos];
   }
 
   [[nodiscard]] constexpr char &at(std::size_t pos) const {
-    if (pos >= m_size) {
-      throw std::out_of_range("StaticString::at: index out of range");
-    }
+    dieIf(pos >= m_size, "StaticString::at: index out of range");
     return m_data[pos];
   }
 
diff --git a/rx/include/rx/die.hpp b/rx/include/rx/die.hpp
index 833001e47..56e6c6bc1 100644
--- a/rx/include/rx/die.hpp
+++ b/rx/include/rx/die.hpp
@@ -1,6 +1,6 @@
 #pragma once
 
-#include "format.hpp"
+#include "format-base.hpp"
 
 namespace rx {
 namespace detail {
diff --git a/rx/include/rx/format-base.hpp b/rx/include/rx/format-base.hpp
index 4baa2c96d..57d5029c8 100644
--- a/rx/include/rx/format-base.hpp
+++ b/rx/include/rx/format-base.hpp
@@ -1,5 +1,7 @@
 #pragma once
 
+#include <source_location>
+
 #ifndef __has_include
 #define __has_include(x) 0
 #endif
@@ -57,3 +59,21 @@ using fmt::vformat;
 using fmt::vformat_to;
 } // namespace rx
 #endif
+
+namespace rx {
+namespace detail {
+template <typename... Args>
+struct format_string_with_location_impl : format_string<Args...> {
+  std::source_location location;
+
+  template <typename T>
+  constexpr format_string_with_location_impl(
+      T message,
+      std::source_location location = std::source_location::current())
+      : format_string<Args...>(message), location(location) {}
+};
+} // namespace detail
+template <typename... Args>
+using format_string_with_location =
+    std::type_identity_t<detail::format_string_with_location_impl<Args...>>;
+} // namespace rx
diff --git a/rx/include/rx/format.hpp b/rx/include/rx/format.hpp
index c5449aade..7beffe405 100644
--- a/rx/include/rx/format.hpp
+++ b/rx/include/rx/format.hpp
@@ -130,22 +130,6 @@ template <auto &&Variable> void registerVariable() {
   auto &storage = detail::getVariableStorage();
   storage.infos[&Variable] = rx::getNameOf<Variable>();
 }
-
-namespace detail {
-template <typename... Args>
-struct format_string_with_location_impl : format_string<Args...> {
-  std::source_location location;
-
-  template <typename T>
-  constexpr format_string_with_location_impl(
-      T message,
-      std::source_location location = std::source_location::current())
-      : format_string<Args...>(message), location(location) {}
-};
-} // namespace detail
-template <typename... Args>
-using format_string_with_location =
-    std::type_identity_t<detail::format_string_with_location_impl<Args...>>;
 } // namespace rx
 
 template <typename T>