6 files changed, 15 insertions, 3 deletions
diff --git a/src/kernel/FSKit/OpenHeFS.h b/src/kernel/FSKit/OpenHeFS.h
index bd5f3753..16647095 100644
--- a/src/kernel/FSKit/OpenHeFS.h
+++ b/src/kernel/FSKit/OpenHeFS.h
@@ -9,8 +9,8 @@
 #include <CompilerKit/CompilerKit.h>
 #include <KernelKit/DriveMgr.h>
 #include <KernelKit/UserMgr.h>
-#include <NeKit/Crc32.h>
 #include <NeKit/Config.h>
+#include <NeKit/Crc32.h>
 #include <NeKit/KString.h>
 #include <hint/CompilerHint.h>
 
diff --git a/src/kernel/KernelKit/UserProcessScheduler.h b/src/kernel/KernelKit/UserProcessScheduler.h
index d67d54c2..6a6cfd61 100644
--- a/src/kernel/KernelKit/UserProcessScheduler.h
+++ b/src/kernel/KernelKit/UserProcessScheduler.h
@@ -37,6 +37,8 @@ class USER_PROCESS final NE_VETTABLE {
   explicit USER_PROCESS();
   ~USER_PROCESS();
 
+  auto DoVet() const { return *this; }
+
  public:
   NE_COPY_DEFAULT(USER_PROCESS)
 
diff --git a/src/kernel/NeKit/OwnPtr.h b/src/kernel/NeKit/OwnPtr.h
index 30c8f9eb..2c493b1b 100644
--- a/src/kernel/NeKit/OwnPtr.h
+++ b/src/kernel/NeKit/OwnPtr.h
@@ -50,7 +50,7 @@ class OwnPtr final {
   Ref<T> AsRef() { return Ref<T>(fCls); }
 
   explicit operator bool() { return fCls; }
-  bool operator!() { return !fCls; }
+  bool     operator!() { return !fCls; }
 
  private:
   T* fCls{nullptr};
diff --git a/src/kernel/NeKit/Pmm.h b/src/kernel/NeKit/Pmm.h
index 8c117a67..7026c583 100644
--- a/src/kernel/NeKit/Pmm.h
+++ b/src/kernel/NeKit/Pmm.h
@@ -7,6 +7,7 @@
 
 #pragma once
 
+#include <NeKit/Config.h>
 #include <NeKit/PageMgr.h>
 #include <NeKit/Ref.h>
 
diff --git a/src/kernel/NeKit/Ref.h b/src/kernel/NeKit/Ref.h
index ff8731e3..da7fe93e 100644
--- a/src/kernel/NeKit/Ref.h
+++ b/src/kernel/NeKit/Ref.h
@@ -45,6 +45,7 @@ class Ref final {
   T operator*() { return fClass; }
 
   operator bool() { return Vettable<T>::kValue; }
+  bool operator!() { return !Vettable<T>::kValue; }
 
  private:
   T fClass;
diff --git a/src/kernel/NeKit/Vet.h b/src/kernel/NeKit/Vet.h
index d4c1060f..86874085 100644
--- a/src/kernel/NeKit/Vet.h
+++ b/src/kernel/NeKit/Vet.h
@@ -13,13 +13,15 @@
 #define NE_VETTABLE : public IVet
 
 namespace Kernel {
+/// @brief Vet interface for objects.
 struct IVet {
   IVet()          = default;
   virtual ~IVet() = default;
 
   NE_COPY_DEFAULT(IVet)
 
-  operator bool() = delete;
+  /// @brief Start vetting object for validity.
+  auto DoVet() const { return false; }
 };
 
 template <typename T>
@@ -31,4 +33,10 @@ template <>
 struct Vettable<IVet> final {
   static constexpr bool kValue = true;
 };
+
+/// @brief Concept version of Vettable.
+template <typename T, typename Fallback>
+concept IVettable = requires(IVet vettable, Fallback fallback) {
+  { Vettable<T>::kValue ? vettable.DoVet() : fallback(vettable) };
+};
 }  // namespace Kernel
 \ No newline at end of file