diff --git a/hist/histv7/inc/ROOT/RAxes.hxx b/hist/histv7/inc/ROOT/RAxes.hxx
index 19848da1be1c3..e8710ec640a98 100644
--- a/hist/histv7/inc/ROOT/RAxes.hxx
+++ b/hist/histv7/inc/ROOT/RAxes.hxx
@@ -21,7 +21,6 @@
 #include <tuple>
 #include <type_traits>
 #include <utility>
-#include <variant>
 #include <vector>
 
 class TBuffer;
diff --git a/hist/histv7/inc/ROOT/RAxisVariant.hxx b/hist/histv7/inc/ROOT/RAxisVariant.hxx
index 9884003460c6e..bf945da177518 100644
--- a/hist/histv7/inc/ROOT/RAxisVariant.hxx
+++ b/hist/histv7/inc/ROOT/RAxisVariant.hxx
@@ -5,8 +5,11 @@
 #ifndef ROOT_RAxisVariant
 #define ROOT_RAxisVariant
 
+#include "RBinIndex.hxx"
+#include "RBinIndexRange.hxx"
 #include "RCategoricalAxis.hxx"
 #include "RRegularAxis.hxx"
+#include "RSliceSpec.hxx"
 #include "RVariableBinAxis.hxx"
 
 #include <cstdint>
diff --git a/hist/histv7/inc/ROOT/RBinIndexMultiDimRange.hxx b/hist/histv7/inc/ROOT/RBinIndexMultiDimRange.hxx
index 2b8541503feb4..7bb2938cbb037 100644
--- a/hist/histv7/inc/ROOT/RBinIndexMultiDimRange.hxx
+++ b/hist/histv7/inc/ROOT/RBinIndexMultiDimRange.hxx
@@ -8,9 +8,7 @@
 #include "RBinIndex.hxx"
 #include "RBinIndexRange.hxx"
 
-#include <cassert>
 #include <cstddef>
-#include <cstdint>
 #include <iterator>
 #include <utility>
 #include <vector>
diff --git a/hist/histv7/inc/ROOT/RHist.hxx b/hist/histv7/inc/ROOT/RHist.hxx
index 05e67ee08a60d..207240353c2bb 100644
--- a/hist/histv7/inc/ROOT/RHist.hxx
+++ b/hist/histv7/inc/ROOT/RHist.hxx
@@ -12,15 +12,17 @@
 #include "RHistEngine.hxx"
 #include "RHistStats.hxx"
 #include "RRegularAxis.hxx"
+#include "RSliceSpec.hxx"
 #include "RWeight.hxx"
 
 #include <array>
+#include <cassert>
 #include <cstddef>
 #include <cstdint>
+#include <initializer_list>
 #include <stdexcept>
 #include <tuple>
 #include <utility>
-#include <variant>
 #include <vector>
 
 class TBuffer;
diff --git a/hist/histv7/inc/ROOT/RHistEngine.hxx b/hist/histv7/inc/ROOT/RHistEngine.hxx
index 4a6003445083d..f438e60b2c789 100644
--- a/hist/histv7/inc/ROOT/RHistEngine.hxx
+++ b/hist/histv7/inc/ROOT/RHistEngine.hxx
@@ -20,6 +20,7 @@
 #include <cassert>
 #include <cstddef>
 #include <cstdint>
+#include <initializer_list>
 #include <stdexcept>
 #include <tuple>
 #include <type_traits>
diff --git a/hist/histv7/inc/ROOT/RHistFillContext.hxx b/hist/histv7/inc/ROOT/RHistFillContext.hxx
index 12aa39ddb2b02..ccbdc727c63e4 100644
--- a/hist/histv7/inc/ROOT/RHistFillContext.hxx
+++ b/hist/histv7/inc/ROOT/RHistFillContext.hxx
@@ -10,6 +10,7 @@
 #include "RHistStats.hxx"
 #include "RWeight.hxx"
 
+#include <cstddef>
 #include <tuple>
 
 namespace ROOT {
diff --git a/hist/histv7/inc/ROOT/RHistUtils.hxx b/hist/histv7/inc/ROOT/RHistUtils.hxx
index ac3ca89aee964..452819ab4739b 100644
--- a/hist/histv7/inc/ROOT/RHistUtils.hxx
+++ b/hist/histv7/inc/ROOT/RHistUtils.hxx
@@ -5,10 +5,12 @@
 #ifndef ROOT_RHistUtils
 #define ROOT_RHistUtils
 
-#include <atomic>
 #include <type_traits>
 
 #ifdef _MSC_VER
+#include <atomic>
+#include <cstddef>
+
 #include <intrin.h>
 #endif
 
diff --git a/hist/histv7/inc/ROOT/RSliceBinIndexMapper.hxx b/hist/histv7/inc/ROOT/RSliceBinIndexMapper.hxx
index dc52f078968bc..d5a59a7a0fca6 100644
--- a/hist/histv7/inc/ROOT/RSliceBinIndexMapper.hxx
+++ b/hist/histv7/inc/ROOT/RSliceBinIndexMapper.hxx
@@ -9,7 +9,8 @@
 #include "RBinIndexRange.hxx"
 #include "RSliceSpec.hxx"
 
-#include <cstdint>
+#include <cassert>
+#include <cstddef>
 #include <stdexcept>
 #include <utility>
 #include <vector>