diff --git a/nac3core/irrt/irrt.cpp b/nac3core/irrt/irrt.cpp
index 404681c..7966322 100644
--- a/nac3core/irrt/irrt.cpp
+++ b/nac3core/irrt/irrt.cpp
@@ -1,5 +1,4 @@
 #include "irrt/exception.hpp"
-#include "irrt/int_types.hpp"
 #include "irrt/list.hpp"
 #include "irrt/math.hpp"
 #include "irrt/ndarray.hpp"
diff --git a/nac3core/irrt/irrt/cslice.hpp b/nac3core/irrt/irrt/cslice.hpp
index 6f1d0a2..41441d3 100644
--- a/nac3core/irrt/irrt/cslice.hpp
+++ b/nac3core/irrt/irrt/cslice.hpp
@@ -4,6 +4,6 @@
 
 template<typename SizeT>
 struct CSlice {
-    uint8_t* base;
+    void* base;
     SizeT len;
 };
\ No newline at end of file
diff --git a/nac3core/irrt/irrt/exception.hpp b/nac3core/irrt/irrt/exception.hpp
index 4a4b093..78accbc 100644
--- a/nac3core/irrt/irrt/exception.hpp
+++ b/nac3core/irrt/irrt/exception.hpp
@@ -6,7 +6,7 @@
 /**
  * @brief The int type of ARTIQ exception IDs.
  */
-typedef int32_t ExceptionId;
+using ExceptionId = int32_t;
 
 /*
  * Set of exceptions C++ IRRT can use.
@@ -55,14 +55,14 @@ void _raise_exception_helper(ExceptionId id,
                              int64_t param2) {
     Exception<SizeT> e = {
         .id = id,
-        .filename = {.base = reinterpret_cast<uint8_t*>(const_cast<char*>(filename)),
-                     .len = static_cast<int32_t>(__builtin_strlen(filename))},
+        .filename = {.base = reinterpret_cast<void*>(const_cast<char*>(filename)),
+                     .len = static_cast<SizeT>(__builtin_strlen(filename))},
         .line = line,
         .column = 0,
-        .function = {.base = reinterpret_cast<uint8_t*>(const_cast<char*>(function)),
-                     .len = static_cast<int32_t>(__builtin_strlen(function))},
-        .msg = {.base = reinterpret_cast<uint8_t*>(const_cast<char*>(msg)),
-                .len = static_cast<int32_t>(__builtin_strlen(msg))},
+        .function = {.base = reinterpret_cast<void*>(const_cast<char*>(function)),
+                     .len = static_cast<SizeT>(__builtin_strlen(function))},
+        .msg = {.base = reinterpret_cast<void*>(const_cast<char*>(msg)),
+                .len = static_cast<SizeT>(__builtin_strlen(msg))},
     };
     e.params[0] = param0;
     e.params[1] = param1;
@@ -70,6 +70,7 @@ void _raise_exception_helper(ExceptionId id,
     __nac3_raise(reinterpret_cast<void*>(&e));
     __builtin_unreachable();
 }
+}  // namespace
 
 /**
  * @brief Raise an exception with location details (location in the IRRT source files).
@@ -82,4 +83,3 @@ void _raise_exception_helper(ExceptionId id,
  */
 #define raise_exception(SizeT, id, msg, param0, param1, param2) \
     _raise_exception_helper<SizeT>(id, __FILE__, __LINE__, __FUNCTION__, msg, param0, param1, param2)
-}  // namespace
\ No newline at end of file
diff --git a/nac3core/irrt/irrt/int_types.hpp b/nac3core/irrt/irrt/int_types.hpp
index 656a060..e25e732 100644
--- a/nac3core/irrt/irrt/int_types.hpp
+++ b/nac3core/irrt/irrt/int_types.hpp
@@ -1,20 +1,11 @@
 #pragma once
 
-#if __STDC_VERSION__ >= 202000
 using int8_t = _BitInt(8);
 using uint8_t = unsigned _BitInt(8);
 using int32_t = _BitInt(32);
 using uint32_t = unsigned _BitInt(32);
 using int64_t = _BitInt(64);
 using uint64_t = unsigned _BitInt(64);
-#else
-using int8_t = _ExtInt(8);
-using uint8_t = unsigned _ExtInt(8);
-using int32_t = _ExtInt(32);
-using uint32_t = unsigned _ExtInt(32);
-using int64_t = _ExtInt(64);
-using uint64_t = unsigned _ExtInt(64);
-#endif
 
 // NDArray indices are always `uint32_t`.
 using NDIndex = uint32_t;
diff --git a/nac3core/irrt/irrt/list.hpp b/nac3core/irrt/irrt/list.hpp
index b389197..2854394 100644
--- a/nac3core/irrt/irrt/list.hpp
+++ b/nac3core/irrt/irrt/list.hpp
@@ -13,12 +13,12 @@ extern "C" {
 SliceIndex __nac3_list_slice_assign_var_size(SliceIndex dest_start,
                                              SliceIndex dest_end,
                                              SliceIndex dest_step,
-                                             uint8_t* dest_arr,
+                                             void* dest_arr,
                                              SliceIndex dest_arr_len,
                                              SliceIndex src_start,
                                              SliceIndex src_end,
                                              SliceIndex src_step,
-                                             uint8_t* src_arr,
+                                             void* src_arr,
                                              SliceIndex src_arr_len,
                                              const SliceIndex size) {
     /* if dest_arr_len == 0, do nothing since we do not support extending list */
@@ -29,11 +29,13 @@ SliceIndex __nac3_list_slice_assign_var_size(SliceIndex dest_start,
         const SliceIndex src_len = (src_end >= src_start) ? (src_end - src_start + 1) : 0;
         const SliceIndex dest_len = (dest_end >= dest_start) ? (dest_end - dest_start + 1) : 0;
         if (src_len > 0) {
-            __builtin_memmove(dest_arr + dest_start * size, src_arr + src_start * size, src_len * size);
+            __builtin_memmove(static_cast<uint8_t*>(dest_arr) + dest_start * size,
+                              static_cast<uint8_t*>(src_arr) + src_start * size, src_len * size);
         }
         if (dest_len > 0) {
             /* dropping */
-            __builtin_memmove(dest_arr + (dest_start + src_len) * size, dest_arr + (dest_end + 1) * size,
+            __builtin_memmove(static_cast<uint8_t*>(dest_arr) + (dest_start + src_len) * size,
+                              static_cast<uint8_t*>(dest_arr) + (dest_end + 1) * size,
                               (dest_arr_len - dest_end - 1) * size);
         }
         /* shrink size */
@@ -44,7 +46,7 @@ SliceIndex __nac3_list_slice_assign_var_size(SliceIndex dest_start,
                           && !(max(dest_start, dest_end) < min(src_start, src_end)
                                || max(src_start, src_end) < min(dest_start, dest_end));
     if (need_alloca) {
-        uint8_t* tmp = reinterpret_cast<uint8_t*>(__builtin_alloca(src_arr_len * size));
+        void* tmp = __builtin_alloca(src_arr_len * size);
         __builtin_memcpy(tmp, src_arr, src_arr_len * size);
         src_arr = tmp;
     }
@@ -53,20 +55,24 @@ SliceIndex __nac3_list_slice_assign_var_size(SliceIndex dest_start,
     for (; (src_step > 0) ? (src_ind <= src_end) : (src_ind >= src_end); src_ind += src_step, dest_ind += dest_step) {
         /* for constant optimization */
         if (size == 1) {
-            __builtin_memcpy(dest_arr + dest_ind, src_arr + src_ind, 1);
+            __builtin_memcpy(static_cast<uint8_t*>(dest_arr) + dest_ind, static_cast<uint8_t*>(src_arr) + src_ind, 1);
         } else if (size == 4) {
-            __builtin_memcpy(dest_arr + dest_ind * 4, src_arr + src_ind * 4, 4);
+            __builtin_memcpy(static_cast<uint8_t*>(dest_arr) + dest_ind * 4,
+                             static_cast<uint8_t*>(src_arr) + src_ind * 4, 4);
         } else if (size == 8) {
-            __builtin_memcpy(dest_arr + dest_ind * 8, src_arr + src_ind * 8, 8);
+            __builtin_memcpy(static_cast<uint8_t*>(dest_arr) + dest_ind * 8,
+                             static_cast<uint8_t*>(src_arr) + src_ind * 8, 8);
         } else {
             /* memcpy for var size, cannot overlap after previous alloca */
-            __builtin_memcpy(dest_arr + dest_ind * size, src_arr + src_ind * size, size);
+            __builtin_memcpy(static_cast<uint8_t*>(dest_arr) + dest_ind * size,
+                             static_cast<uint8_t*>(src_arr) + src_ind * size, size);
         }
     }
     /* only dest_step == 1 can we shrink the dest list. */
     /* size should be ensured prior to calling this function */
     if (dest_step == 1 && dest_end >= dest_start) {
-        __builtin_memmove(dest_arr + dest_ind * size, dest_arr + (dest_end + 1) * size,
+        __builtin_memmove(static_cast<uint8_t*>(dest_arr) + dest_ind * size,
+                          static_cast<uint8_t*>(dest_arr) + (dest_end + 1) * size,
                           (dest_arr_len - dest_end - 1) * size);
         return dest_arr_len - (dest_end - dest_ind) - 1;
     }
diff --git a/nac3core/irrt/irrt/math.hpp b/nac3core/irrt/irrt/math.hpp
index ff10f3f..1872f56 100644
--- a/nac3core/irrt/irrt/math.hpp
+++ b/nac3core/irrt/irrt/math.hpp
@@ -90,4 +90,4 @@ double __nac3_j0(double x) {
 
     return j0(x);
 }
-}
\ No newline at end of file
+}  // namespace
\ No newline at end of file
diff --git a/nac3core/irrt/irrt/ndarray.hpp b/nac3core/irrt/irrt/ndarray.hpp
index 5dda173..b239152 100644
--- a/nac3core/irrt/irrt/ndarray.hpp
+++ b/nac3core/irrt/irrt/ndarray.hpp
@@ -141,4 +141,4 @@ void __nac3_ndarray_calc_broadcast_idx64(const uint64_t* src_dims,
                                          NDIndex* out_idx) {
     __nac3_ndarray_calc_broadcast_idx_impl(src_dims, src_ndims, in_idx, out_idx);
 }
-}
\ No newline at end of file
+}  // namespace
\ No newline at end of file
diff --git a/nac3core/irrt/irrt/slice.hpp b/nac3core/irrt/irrt/slice.hpp
index a1523dd..3f6d83a 100644
--- a/nac3core/irrt/irrt/slice.hpp
+++ b/nac3core/irrt/irrt/slice.hpp
@@ -25,4 +25,4 @@ SliceIndex __nac3_range_slice_len(const SliceIndex start, const SliceIndex end,
         return 0;
     }
 }
-}
\ No newline at end of file
+}  // namespace
\ No newline at end of file