diff --git a/ascii.hpp b/ascii.hpp
index 70ded52e..11f6d106 100644
--- a/ascii.hpp
+++ b/ascii.hpp
@@ -11,9 +11,11 @@
 #include "annotation.hpp"
 #include "debug/assert.hpp"
 
+#include <array>
 #include <cstdint>
 #include <stdexcept>
 
+
 namespace cruft::ascii {
     ///////////////////////////////////////////////////////////////////////////
     /// Returns true if the supplied character is an ASCII digit.
diff --git a/bitwise.hpp b/bitwise.hpp
index 2d8f3827..f4a0ec4c 100644
--- a/bitwise.hpp
+++ b/bitwise.hpp
@@ -10,7 +10,9 @@
 
 #include "debug/assert.hpp"
 
+#include <tuple>
 #include <type_traits>
+
 #include <cstdint>
 
 
diff --git a/cast.hpp b/cast.hpp
index af04b038..03de1419 100644
--- a/cast.hpp
+++ b/cast.hpp
@@ -18,6 +18,7 @@
 #include <limits>
 
 #include <cstring>
+#include <cmath>
 
 
 namespace cruft::cast {
diff --git a/debug/assert.hpp b/debug/assert.hpp
index c61cd9ae..260cdabb 100644
--- a/debug/assert.hpp
+++ b/debug/assert.hpp
@@ -8,9 +8,10 @@
 
 #pragma once
 
+#include "./panic.hpp"
 #include "../platform.hpp"
+#include "../maths.hpp"
 
-//#include "maths.hpp" // XXX: See notes at the end of file for maths.hpp inclusion
 #include "debugger.hpp"
 
 #include <utility>
@@ -422,10 +423,3 @@ warn_return (
     warn (message);
     return std::forward<ValueT> (value);
 }
-
-
-///////////////////////////////////////////////////////////////////////////////
-// XXX: maths needs to be included so that CHECK_EQ/NEQ can call almost_equal,
-// but maths.hpp might be using CHECK_ macros so we must include maths.hpp
-// after we define the CHECK_ macros so the preprocessor can resolve them.
-#include "../maths.hpp"
diff --git a/debug/validate.hpp b/debug/validate.hpp
index 8bb3a150..96c548c0 100644
--- a/debug/validate.hpp
+++ b/debug/validate.hpp
@@ -7,6 +7,9 @@
  */
 
 #pragma once
+
+#include "./assert.hpp"
+
 ///////////////////////////////////////////////////////////////////////////////
 namespace cruft::debug {
     ///////////////////////////////////////////////////////////////////////////
diff --git a/parse/enum.hpp b/parse/enum.hpp
index 1338f1c7..90004bd7 100644
--- a/parse/enum.hpp
+++ b/parse/enum.hpp
@@ -13,6 +13,7 @@
 #include "../view.hpp"
 #include "../introspection/name.hpp"
 #include "../log.hpp"
+#include "../typeidx.hpp"
 
 #include <map>
 
diff --git a/types/description.cpp b/types/description.cpp
index 6b9967ec..0b6aba38 100644
--- a/types/description.cpp
+++ b/types/description.cpp
@@ -9,6 +9,7 @@
 #include "description.hpp"
 
 #include "../debug/assert.hpp"
+#include "../maths.hpp"
 
 
 ///////////////////////////////////////////////////////////////////////////////
diff --git a/view.hpp b/view.hpp
index 922bddb9..3b6bc80e 100644
--- a/view.hpp
+++ b/view.hpp
@@ -978,6 +978,8 @@ namespace cruft {
 }
 
 
+#include "debug/validate.hpp"
+
 namespace cruft::debug {
     ///////////////////////////////////////////////////////////////////////////
     template <typename IteratorT, typename ...ArgsT>