5 files changed, 25 insertions, 24 deletions
diff --git a/compat/check-visible.cpp b/compat/check-visible.cpp
index 0f4c6e6d..0e154dd0 100644
--- a/compat/check-visible.cpp
+++ b/compat/check-visible.cpp
@@ -4,7 +4,7 @@
 
 #include "timer.hpp"
 
-#include <QMutexLocker>
+#include <QMutex>
 
 #include <windows.h>
 
diff --git a/compat/correlation-calibrator.cpp b/compat/correlation-calibrator.cpp
index 70455818..b2e83153 100644
--- a/compat/correlation-calibrator.cpp
+++ b/compat/correlation-calibrator.cpp
@@ -61,7 +61,7 @@ bool correlation_calibrator::check_buckets(const vec6& data)
 
         if (pos[k] >= nbuckets[k])
         {
-            once_only(qDebug() << "idx" << k
+            eval_once(qDebug() << "idx" << k
                                << "bucket" << (int)pos[k]
                                << "outside bounds" << nbuckets[k]);
 
diff --git a/compat/macros.hpp b/compat/macros.hpp
index 61c49975..0807df4c 100644
--- a/compat/macros.hpp
+++ b/compat/macros.hpp
@@ -44,8 +44,13 @@
 
 // from now only C++
 
+#include <utility>
+
 //#define once_only(...) do { static bool once__ = false; if (!once__) { once__ = true; __VA_ARGS__; } } while(false)
-#define once_only(expr) ([&] { static decltype(auto) ret___1132 = (expr); return ret___1132; }())
+//#define once_only(expr) ([&] { static decltype(auto) ret___1132 = (expr); return (decltype(ret___1132) const&) ret___1132; }())
+
+#define eval_once__2(expr, ident) (([&] { static bool ident = ((expr), true); (void)(ident); }))
+#define eval_once(expr) eval_once__2(expr, PP_CAT(eval_once_init__, __COUNTER__))
 
 #include <type_traits>
 
diff --git a/compat/meta.hpp b/compat/meta.hpp
index 8682fdc8..11c5ca0f 100644
--- a/compat/meta.hpp
+++ b/compat/meta.hpp
@@ -11,9 +11,7 @@
     static_assert(sizeof...(x) == ~0ul);                             \
     static_assert(sizeof...(x) == 0u)
 
-namespace meta {
-
-namespace detail {
+namespace meta::detail {
 
     template<typename... xs>
     struct tuple;
@@ -47,27 +45,26 @@ namespace detail {
     {
         using type = to<xs...>;
     };
-} // ns detail
-
-
-template<typename... xs>
-using reverse = typename detail::reverse_<detail::tuple<xs...>, detail::tuple<>>::type;
+} // ns meta::detail
 
-// the to/from order is awkward but mimics function composition
-template<template<typename...> class to, typename from>
-using lift = typename detail::lift_<to, from>::type;
+namespace meta {
+    template<typename... xs>
+    using reverse = typename detail::reverse_<detail::tuple<xs...>, detail::tuple<>>::type;
 
-template<typename x, typename... xs>
-using first = x;
+    // the to/from order is awkward but mimics function composition
+    template<template<typename...> class to, typename from>
+    using lift = typename detail::lift_<to, from>::type;
 
-template<typename x, typename... xs>
-using rest = detail::tuple<xs...>;
+    template<typename x, typename... xs>
+    using first = x;
 
-template<typename... xs>
-using butlast = reverse<rest<reverse<xs...>>>;
+    template<typename x, typename... xs>
+    using rest = detail::tuple<xs...>;
 
-template<typename... xs>
-using last = lift<first, reverse<xs...>>;
+    template<typename... xs>
+    using butlast = reverse<rest<reverse<xs...>>>;
 
+    template<typename... xs>
+    using last = lift<first, reverse<xs...>>;
 } // ns meta
 
diff --git a/compat/timer.cpp b/compat/timer.cpp
index dc9808b1..b9664263 100644
--- a/compat/timer.cpp
+++ b/compat/timer.cpp
@@ -6,9 +6,8 @@
  * notice appear in all copies.
  */
 
-#include <cassert>
-
 #include "timer.hpp"
+#include <cassert>
 #include <cmath>
 
 using time_type = Timer::time_type;