diff --git a/src/common/x64/xbyak_abi.h b/src/common/x64/xbyak_abi.h
index fd3fbdd4b..a27f5c72d 100644
--- a/src/common/x64/xbyak_abi.h
+++ b/src/common/x64/xbyak_abi.h
@@ -9,8 +9,7 @@
 #include "common/assert.h"
 #include "common/bit_set.h"
 
-namespace Common {
-namespace X64 {
+namespace Common::X64 {
 
 int RegToIndex(const Xbyak::Reg& reg) {
     using Kind = Xbyak::Reg::Kind;
@@ -217,5 +216,4 @@ void ABI_PopRegistersAndAdjustStack(Xbyak::CodeGenerator& code, BitSet32 regs, s
     }
 }
 
-} // namespace X64
-} // namespace Common
+} // namespace Common::X64
diff --git a/src/common/x64/xbyak_util.h b/src/common/x64/xbyak_util.h
index ec76e0a47..02323a017 100644
--- a/src/common/x64/xbyak_util.h
+++ b/src/common/x64/xbyak_util.h
@@ -8,8 +8,7 @@
 #include <xbyak.h>
 #include "common/x64/xbyak_abi.h"
 
-namespace Common {
-namespace X64 {
+namespace Common::X64 {
 
 // Constants for use with cmpps/cmpss
 enum {
@@ -45,5 +44,4 @@ inline void CallFarFunction(Xbyak::CodeGenerator& code, const T f) {
     }
 }
 
-} // namespace X64
-} // namespace Common
+} // namespace Common::X64