Print stack trace on assertion fail

kernel/src/Log.cpp

@@ -118,10 +118,12 @@ static bool g_check_already_failed = false;
 
 [[noreturn]] bool __check_failed(const char* file, const char* line, const char* func, const char* expr)
 {
+    CPU::disable_interrupts();
     if (!g_check_already_failed)
     { // Avoid endlessly failing when trying to report a failed check.
         g_check_already_failed = true;
         kerrorln("ERROR: Check failed at %s:%s, in %s: %s", file, line, func, expr);
+        CPU::print_stack_trace();
     }
     CPU::efficient_halt();
 }

luna/include/luna/OwnedStringView.h

@@ -22,11 +22,7 @@ class OwnedStringView
         return m_length;
     }
 
-    const char& operator[](usize index) const
+    const char& operator[](usize) const;
-    {
-        expect(index < m_length, "OwnedStringView: index out of range");
-        return m_string[index];
-    }
 
   private:
     char* m_string{nullptr};

luna/src/OwnedStringView.cpp

@@ -34,3 +34,9 @@ Result<OwnedStringView> OwnedStringView::clone() const
 
     return OwnedStringView{c_str};
 }
+
+const char& OwnedStringView::operator[](usize index) const
+{
+    expect(index < m_length, "index out of range");
+    return m_string[index];
+}