diff --git a/qpms/indexing.h b/qpms/indexing.h
index 86ea952..e8ef012 100644
--- a/qpms/indexing.h
+++ b/qpms/indexing.h
@@ -109,7 +109,7 @@ static const qpms_uvswfi_t QPMS_UI_L00 = 0;
 /** Returns a non-zero value if the u value is invalid. */
 static inline qpms_errno_t qpms_uvswfi2tmn(qpms_uvswfi_t u,
 		qpms_vswf_type_t *t, qpms_m_t *m, qpms_l_t *n) {
-	*t = u & 3;
+	*t = (qpms_vswf_type_t)(u & 3);
 	qpms_y_sc_t y_sc = u / 4;
 	qpms_y2mn_sc_p(y_sc, m, n);
 	// Test validity
@@ -122,7 +122,7 @@ static inline qpms_errno_t qpms_uvswfi2tmn(qpms_uvswfi_t u,
 /** Does *not* allow for longitudinal waves. */
 static inline qpms_errno_t qpms_uvswfi2ty(qpms_uvswfi_t u,
 		qpms_vswf_type_t *t, qpms_y_t *y) {
-	*t = u & 3;
+	*t = (qpms_vswf_type_t)(u & 3);
 	*y = u / 4 - 1;
 	if (QPMS_UNLIKELY(*t == 0 || *t == 3)) return QPMS_ERROR;
 	if (QPMS_UNLIKELY(*y < 0)) return QPMS_ERROR;
@@ -135,7 +135,7 @@ static inline qpms_errno_t qpms_uvswfi2ty(qpms_uvswfi_t u,
  */
 static inline qpms_errno_t qpms_uvswfi2ty_l(qpms_uvswfi_t u,
 		qpms_vswf_type_t *t, qpms_y_t *y) {
-	*t = u & 3;
+	*t = (qpms_vswf_type_t)(u & 3);
 	*y = u / 4 - 1;
 	if (QPMS_UNLIKELY(*t == 3)) return QPMS_ERROR;
 	if (QPMS_UNLIKELY(*y < 0)) return QPMS_ERROR;
diff --git a/qpms/lattices.h b/qpms/lattices.h
index d7bdac0..395a184 100644
--- a/qpms/lattices.h
+++ b/qpms/lattices.h
@@ -1,6 +1,7 @@
 /*! \file lattices.h
  * \brief Lattice point generators and lattice vector analysis / transformation.
  *
+ * \bug Header file not C++ compatible.
  */
 #ifndef LATTICES_H
 #define LATTICES_H
diff --git a/qpms/normalisation.h b/qpms/normalisation.h
index 2b72f82..a282231 100644
--- a/qpms/normalisation.h
+++ b/qpms/normalisation.h
@@ -2,10 +2,12 @@
  * \brief Convention-dependent coefficients for VSWFs.
  *
  * See also @ref qpms_normalisation_t and @ref vswf_conventions.
+ *
+ * \bug Header file not C++ compatible.
  */
 #ifndef NORMALISATION_H
 #define NORMALISATION_H
-#ifdef __cplusplus
+#ifdef __cplusplus //FIXME not C++ compatible yet (enum bit operations)
 extern "C" {
 #endif
 
diff --git a/tests/catch/all_includes.C b/tests/catch/all_includes.C
index 10f3e9a..7147355 100644
--- a/tests/catch/all_includes.C
+++ b/tests/catch/all_includes.C
@@ -1,8 +1,7 @@
 // Just to test that all headers are C++ compatible
 #include <catch2/catch.hpp>
-extern "C" {
 #include <vswf.h>
-//#include <beyn.h> // C++ keyword as an identifier
+#include <beyn.h>
 #include <gaunt.h>
 #include <groups.h>
 #include <kahansum.h>
@@ -18,14 +17,14 @@ extern "C" {
 #include <tiny_inlines.h>
 #include <tmatrices.h>
 #include <tolerances.h>
+#include <translations.h>
+#include <vectors.h>
+#include <pointgroups.h>
+#include <lattices_types.h>
+#include <indexing.h>
+#include <ewald.h>
 // C++ type conversion issues:
+#include <quaternions.h>
 //#include <lattices.h>
 //#include <normalisation.h>
-//#include <indexing.h>
-//#include <pointgroups.h>
 //#include <qpmsblas.h>
-//#include <quaternions.h>
-//#include <ewald.h>
-//#include <translations.h>
-//#include <vectors.h>
-}