diff --git a/cpp2rust/converter/converter_lib.cpp b/cpp2rust/converter/converter_lib.cpp
index f932fa23..2ce0f85e 100644
--- a/cpp2rust/converter/converter_lib.cpp
+++ b/cpp2rust/converter/converter_lib.cpp
@@ -207,10 +207,6 @@ bool TypeImplementsByteRepr(clang::QualType qt) {
     return TypeImplementsByteRepr(arr->getElementType());
   }
   if (const auto *rd = qt->getAsRecordDecl()) {
-    if (rd->getASTContext().getSourceManager().isInSystemHeader(
-            rd->getLocation())) {
-      return false;
-    }
     if (rd->isUnion()) {
       return true;
     }
diff --git a/tests/unit/out/refcount/array_of_noncopy_struct.rs b/tests/unit/out/refcount/array_of_noncopy_struct.rs
index 3d31d3a9..bfd0462f 100644
--- a/tests/unit/out/refcount/array_of_noncopy_struct.rs
+++ b/tests/unit/out/refcount/array_of_noncopy_struct.rs
@@ -20,7 +20,21 @@ impl Clone for NonCopy {
         this
     }
 }
-impl ByteRepr for NonCopy {}
+impl ByteRepr for NonCopy {
+    fn byte_size() -> usize {
+        32
+    }
+    fn to_bytes(&self, buf: &mut [u8]) {
+        (*self.data.borrow()).to_bytes(&mut buf[0..24]);
+        (*self.tag.borrow()).to_bytes(&mut buf[24..28]);
+    }
+    fn from_bytes(buf: &[u8]) -> Self {
+        Self {
+            data: Rc::new(RefCell::new(<Vec<i32>>::from_bytes(&buf[0..24]))),
+            tag: Rc::new(RefCell::new(<i32>::from_bytes(&buf[24..28]))),
+        }
+    }
+}
 pub fn main() {
     std::process::exit(main_0());
 }
diff --git a/tests/unit/out/refcount/class_templates.rs b/tests/unit/out/refcount/class_templates.rs
index 3cbce86e..183fbd41 100644
--- a/tests/unit/out/refcount/class_templates.rs
+++ b/tests/unit/out/refcount/class_templates.rs
@@ -42,7 +42,19 @@ impl Clone for MyContainer_int_ {
         this
     }
 }
-impl ByteRepr for MyContainer_int_ {}
+impl ByteRepr for MyContainer_int_ {
+    fn byte_size() -> usize {
+        24
+    }
+    fn to_bytes(&self, buf: &mut [u8]) {
+        (*self.vec_.borrow()).to_bytes(&mut buf[0..24]);
+    }
+    fn from_bytes(buf: &[u8]) -> Self {
+        Self {
+            vec_: Rc::new(RefCell::new(<Vec<i32>>::from_bytes(&buf[0..24]))),
+        }
+    }
+}
 #[derive(Default)]
 pub struct MyContainer_char_ {
     vec_: Value<Vec<u8>>,
@@ -79,7 +91,19 @@ impl Clone for MyContainer_char_ {
         this
     }
 }
-impl ByteRepr for MyContainer_char_ {}
+impl ByteRepr for MyContainer_char_ {
+    fn byte_size() -> usize {
+        24
+    }
+    fn to_bytes(&self, buf: &mut [u8]) {
+        (*self.vec_.borrow()).to_bytes(&mut buf[0..24]);
+    }
+    fn from_bytes(buf: &[u8]) -> Self {
+        Self {
+            vec_: Rc::new(RefCell::new(<Vec<u8>>::from_bytes(&buf[0..24]))),
+        }
+    }
+}
 #[derive(Default)]
 pub struct MyContainer_float_ {
     vec_: Value<Vec<f32>>,
@@ -116,7 +140,19 @@ impl Clone for MyContainer_float_ {
         this
     }
 }
-impl ByteRepr for MyContainer_float_ {}
+impl ByteRepr for MyContainer_float_ {
+    fn byte_size() -> usize {
+        24
+    }
+    fn to_bytes(&self, buf: &mut [u8]) {
+        (*self.vec_.borrow()).to_bytes(&mut buf[0..24]);
+    }
+    fn from_bytes(buf: &[u8]) -> Self {
+        Self {
+            vec_: Rc::new(RefCell::new(<Vec<f32>>::from_bytes(&buf[0..24]))),
+        }
+    }
+}
 pub fn main() {
     std::process::exit(main_0());
 }
diff --git a/tests/unit/out/refcount/foreach_disjoint_field_borrow.rs b/tests/unit/out/refcount/foreach_disjoint_field_borrow.rs
index 66c9e892..57c56051 100644
--- a/tests/unit/out/refcount/foreach_disjoint_field_borrow.rs
+++ b/tests/unit/out/refcount/foreach_disjoint_field_borrow.rs
@@ -20,7 +20,21 @@ impl Clone for S {
         this
     }
 }
-impl ByteRepr for S {}
+impl ByteRepr for S {
+    fn byte_size() -> usize {
+        32
+    }
+    fn to_bytes(&self, buf: &mut [u8]) {
+        (*self.v.borrow()).to_bytes(&mut buf[0..24]);
+        (*self.a.borrow()).to_bytes(&mut buf[24..28]);
+    }
+    fn from_bytes(buf: &[u8]) -> Self {
+        Self {
+            v: Rc::new(RefCell::new(<Vec<i32>>::from_bytes(&buf[0..24]))),
+            a: Rc::new(RefCell::new(<i32>::from_bytes(&buf[24..28]))),
+        }
+    }
+}
 pub fn main() {
     std::process::exit(main_0());
 }
diff --git a/tests/unit/out/refcount/huffman.rs b/tests/unit/out/refcount/huffman.rs
index f023a545..e2f608af 100644
--- a/tests/unit/out/refcount/huffman.rs
+++ b/tests/unit/out/refcount/huffman.rs
@@ -218,7 +218,31 @@ impl MinHeap {
         }
     }
 }
-impl ByteRepr for MinHeap {}
+impl ByteRepr for MinHeap {
+    fn byte_size() -> usize {
+        32
+    }
+    fn to_bytes(&self, buf: &mut [u8]) {
+        (*self.size.borrow()).to_bytes(&mut buf[0..4]);
+        (*self.capacity.borrow()).to_bytes(&mut buf[4..8]);
+        (*self.arr.borrow()).to_bytes(&mut buf[8..16]);
+        (*self.next.borrow()).to_bytes(&mut buf[16..20]);
+        (*self.alloc.borrow()).to_bytes(&mut buf[24..32]);
+    }
+    fn from_bytes(buf: &[u8]) -> Self {
+        Self {
+            size: Rc::new(RefCell::new(<i32>::from_bytes(&buf[0..4]))),
+            capacity: Rc::new(RefCell::new(<i32>::from_bytes(&buf[4..8]))),
+            arr: Rc::new(RefCell::new(
+                <Option<Value<Box<[Ptr<MinHeapNode>]>>>>::from_bytes(&buf[8..16]),
+            )),
+            next: Rc::new(RefCell::new(<i32>::from_bytes(&buf[16..20]))),
+            alloc: Rc::new(RefCell::new(
+                <Option<Value<Box<[MinHeapNode]>>>>::from_bytes(&buf[24..32]),
+            )),
+        }
+    }
+}
 pub fn AllocMinHeap_1(capacity: i32) -> Option<Value<MinHeap>> {
     let capacity: Value<i32> = Rc::new(RefCell::new(capacity));
     let minHeap: Value<Option<Value<MinHeap>>> =
diff --git a/tests/unit/out/refcount/implicit_autoref.rs b/tests/unit/out/refcount/implicit_autoref.rs
index a406be11..0b29d399 100644
--- a/tests/unit/out/refcount/implicit_autoref.rs
+++ b/tests/unit/out/refcount/implicit_autoref.rs
@@ -18,7 +18,19 @@ impl Clone for Holder {
         this
     }
 }
-impl ByteRepr for Holder {}
+impl ByteRepr for Holder {
+    fn byte_size() -> usize {
+        24
+    }
+    fn to_bytes(&self, buf: &mut [u8]) {
+        (*self.v.borrow()).to_bytes(&mut buf[0..24]);
+    }
+    fn from_bytes(buf: &[u8]) -> Self {
+        Self {
+            v: Rc::new(RefCell::new(<Vec<i32>>::from_bytes(&buf[0..24]))),
+        }
+    }
+}
 pub fn write_through_0(p: Ptr<i32>) {
     let p: Value<Ptr<i32>> = Rc::new(RefCell::new(p));
     (*p.borrow()).write(42);
diff --git a/tests/unit/out/refcount/kruskal.rs b/tests/unit/out/refcount/kruskal.rs
index d5277b51..b07c301e 100644
--- a/tests/unit/out/refcount/kruskal.rs
+++ b/tests/unit/out/refcount/kruskal.rs
@@ -280,14 +280,52 @@ impl DisjointSet {
         }
     }
 }
-impl ByteRepr for DisjointSet {}
+impl ByteRepr for DisjointSet {
+    fn byte_size() -> usize {
+        24
+    }
+    fn to_bytes(&self, buf: &mut [u8]) {
+        (*self.rank.borrow()).to_bytes(&mut buf[0..8]);
+        (*self.parent.borrow()).to_bytes(&mut buf[8..16]);
+        (*self.n.borrow()).to_bytes(&mut buf[16..20]);
+    }
+    fn from_bytes(buf: &[u8]) -> Self {
+        Self {
+            rank: Rc::new(RefCell::new(<Option<Value<Box<[i32]>>>>::from_bytes(
+                &buf[0..8],
+            ))),
+            parent: Rc::new(RefCell::new(<Option<Value<Box<[i32]>>>>::from_bytes(
+                &buf[8..16],
+            ))),
+            n: Rc::new(RefCell::new(<i32>::from_bytes(&buf[16..20]))),
+        }
+    }
+}
 #[derive(Default)]
 pub struct Graph {
     pub edges: Value<Option<Value<Box<[Edge]>>>>,
     pub V: Value<i32>,
     pub E: Value<i32>,
 }
-impl ByteRepr for Graph {}
+impl ByteRepr for Graph {
+    fn byte_size() -> usize {
+        16
+    }
+    fn to_bytes(&self, buf: &mut [u8]) {
+        (*self.edges.borrow()).to_bytes(&mut buf[0..8]);
+        (*self.V.borrow()).to_bytes(&mut buf[8..12]);
+        (*self.E.borrow()).to_bytes(&mut buf[12..16]);
+    }
+    fn from_bytes(buf: &[u8]) -> Self {
+        Self {
+            edges: Rc::new(RefCell::new(<Option<Value<Box<[Edge]>>>>::from_bytes(
+                &buf[0..8],
+            ))),
+            V: Rc::new(RefCell::new(<i32>::from_bytes(&buf[8..12]))),
+            E: Rc::new(RefCell::new(<i32>::from_bytes(&buf[12..16]))),
+        }
+    }
+}
 pub fn MSTKruskal_2(graph: Ptr<Graph>) -> f64 {
     ({
         let _arr: Ptr<Option<Value<Box<[Edge]>>>> = (*graph.upgrade().deref()).edges.as_pointer();
diff --git a/tests/unit/out/refcount/libc_struct_without_default.rs b/tests/unit/out/refcount/libc_struct_without_default.rs
index 9e540565..15c703f6 100644
--- a/tests/unit/out/refcount/libc_struct_without_default.rs
+++ b/tests/unit/out/refcount/libc_struct_without_default.rs
@@ -30,7 +30,21 @@ impl Default for UserDefined {
         }
     }
 }
-impl ByteRepr for UserDefined {}
+impl ByteRepr for UserDefined {
+    fn byte_size() -> usize {
+        32
+    }
+    fn to_bytes(&self, buf: &mut [u8]) {
+        (*self.a.borrow()).to_bytes(&mut buf[0..4]);
+        (*self.v.borrow()).to_bytes(&mut buf[8..32]);
+    }
+    fn from_bytes(buf: &[u8]) -> Self {
+        Self {
+            a: Rc::new(RefCell::new(<Vec<i32>>::from_bytes(&buf[0..4]))),
+            v: Rc::new(RefCell::new(<Vec<i32>>::from_bytes(&buf[8..32]))),
+        }
+    }
+}
 #[derive()]
 pub struct FieldIsLibcType {
     pub addr: Value<libcc2rs::Sockaddr>,
@@ -50,7 +64,19 @@ impl Default for FieldIsLibcType {
         }
     }
 }
-impl ByteRepr for FieldIsLibcType {}
+impl ByteRepr for FieldIsLibcType {
+    fn byte_size() -> usize {
+        16
+    }
+    fn to_bytes(&self, buf: &mut [u8]) {
+        (*self.addr.borrow()).to_bytes(&mut buf[0..16]);
+    }
+    fn from_bytes(buf: &[u8]) -> Self {
+        Self {
+            addr: Rc::new(RefCell::new(<libcc2rs::Sockaddr>::from_bytes(&buf[0..16]))),
+        }
+    }
+}
 pub fn main() {
     std::process::exit(main_0());
 }
diff --git a/tests/unit/out/refcount/push_emplace_back.rs b/tests/unit/out/refcount/push_emplace_back.rs
index 07e74001..953a075c 100644
--- a/tests/unit/out/refcount/push_emplace_back.rs
+++ b/tests/unit/out/refcount/push_emplace_back.rs
@@ -84,7 +84,23 @@ impl Clone for JPEGData {
         this
     }
 }
-impl ByteRepr for JPEGData {}
+impl ByteRepr for JPEGData {
+    fn byte_size() -> usize {
+        48
+    }
+    fn to_bytes(&self, buf: &mut [u8]) {
+        (*self.com_data.borrow()).to_bytes(&mut buf[0..24]);
+        (*self.app_data.borrow()).to_bytes(&mut buf[24..48]);
+    }
+    fn from_bytes(buf: &[u8]) -> Self {
+        Self {
+            com_data: Rc::new(RefCell::new(<Vec<Value<Vec<u8>>>>::from_bytes(&buf[0..24]))),
+            app_data: Rc::new(RefCell::new(<Vec<Value<Vec<u8>>>>::from_bytes(
+                &buf[24..48],
+            ))),
+        }
+    }
+}
 pub fn push_param_0(dest: Ptr<Vec<Value<Vec<u8>>>>) {
     let dest: Value<Ptr<Vec<Value<Vec<u8>>>>> = Rc::new(RefCell::new(dest));
     ((*dest.borrow()).to_strong().as_pointer() as Ptr<Vec<Value<Vec<u8>>>>).with_mut(
diff --git a/tests/unit/out/refcount/struct_default_ctor.rs b/tests/unit/out/refcount/struct_default_ctor.rs
index 39e1bd87..62f7e73a 100644
--- a/tests/unit/out/refcount/struct_default_ctor.rs
+++ b/tests/unit/out/refcount/struct_default_ctor.rs
@@ -42,7 +42,23 @@ impl Default for WOFF2Params {
         { WOFF2Params::WOFF2Params() }
     }
 }
-impl ByteRepr for WOFF2Params {}
+impl ByteRepr for WOFF2Params {
+    fn byte_size() -> usize {
+        40
+    }
+    fn to_bytes(&self, buf: &mut [u8]) {
+        (*self.extended_metadata.borrow()).to_bytes(&mut buf[0..32]);
+        (*self.brotli_quality.borrow()).to_bytes(&mut buf[32..36]);
+        (*self.allow_transforms.borrow()).to_bytes(&mut buf[36..37]);
+    }
+    fn from_bytes(buf: &[u8]) -> Self {
+        Self {
+            extended_metadata: Rc::new(RefCell::new(<Vec<u8>>::from_bytes(&buf[0..32]))),
+            brotli_quality: Rc::new(RefCell::new(<i32>::from_bytes(&buf[32..36]))),
+            allow_transforms: Rc::new(RefCell::new(<bool>::from_bytes(&buf[36..37]))),
+        }
+    }
+}
 pub fn main() {
     std::process::exit(main_0());
 }
diff --git a/tests/unit/out/refcount/typedef-anon-struct.rs b/tests/unit/out/refcount/typedef-anon-struct.rs
index ebc6ad42..42c27e37 100644
--- a/tests/unit/out/refcount/typedef-anon-struct.rs
+++ b/tests/unit/out/refcount/typedef-anon-struct.rs
@@ -47,7 +47,19 @@ impl Clone for Outer {
         this
     }
 }
-impl ByteRepr for Outer {}
+impl ByteRepr for Outer {
+    fn byte_size() -> usize {
+        24
+    }
+    fn to_bytes(&self, buf: &mut [u8]) {
+        (*self.runs.borrow()).to_bytes(&mut buf[0..24]);
+    }
+    fn from_bytes(buf: &[u8]) -> Self {
+        Self {
+            runs: Rc::new(RefCell::new(<Vec<Outer_RunInfo>>::from_bytes(&buf[0..24]))),
+        }
+    }
+}
 pub fn main() {
     std::process::exit(main_0());
 }
diff --git a/tests/unit/out/refcount/unique_ptr.rs b/tests/unit/out/refcount/unique_ptr.rs
index 8f570b48..9d4eb0eb 100644
--- a/tests/unit/out/refcount/unique_ptr.rs
+++ b/tests/unit/out/refcount/unique_ptr.rs
@@ -15,7 +15,19 @@ impl SafePointer {
         (*(*self.ptr.borrow_mut()).as_ref().unwrap().borrow_mut()).prefix_inc();
     }
 }
-impl ByteRepr for SafePointer {}
+impl ByteRepr for SafePointer {
+    fn byte_size() -> usize {
+        8
+    }
+    fn to_bytes(&self, buf: &mut [u8]) {
+        (*self.ptr.borrow()).to_bytes(&mut buf[0..8]);
+    }
+    fn from_bytes(buf: &[u8]) -> Self {
+        Self {
+            ptr: Rc::new(RefCell::new(<Option<Value<i32>>>::from_bytes(&buf[0..8]))),
+        }
+    }
+}
 #[derive(Default)]
 pub struct Pair {
     pub x: Value<i32>,
diff --git a/tests/unit/out/refcount/unique_ptr_const_deref.rs b/tests/unit/out/refcount/unique_ptr_const_deref.rs
index ee468020..8763aa17 100644
--- a/tests/unit/out/refcount/unique_ptr_const_deref.rs
+++ b/tests/unit/out/refcount/unique_ptr_const_deref.rs
@@ -10,7 +10,19 @@ use std::rc::{Rc, Weak};
 pub struct Holder {
     pub val: Value<Option<Value<i32>>>,
 }
-impl ByteRepr for Holder {}
+impl ByteRepr for Holder {
+    fn byte_size() -> usize {
+        8
+    }
+    fn to_bytes(&self, buf: &mut [u8]) {
+        (*self.val.borrow()).to_bytes(&mut buf[0..8]);
+    }
+    fn from_bytes(buf: &[u8]) -> Self {
+        Self {
+            val: Rc::new(RefCell::new(<Option<Value<i32>>>::from_bytes(&buf[0..8]))),
+        }
+    }
+}
 pub fn read_val_0(h: Ptr<Holder>) -> i32 {
     let h: Value<Ptr<Holder>> = Rc::new(RefCell::new(h));
     return (*(*(*(*h.borrow()).upgrade().deref()).val.borrow())
diff --git a/tests/unit/out/refcount/unique_ptr_nested.rs b/tests/unit/out/refcount/unique_ptr_nested.rs
index e1ad9181..73a07682 100644
--- a/tests/unit/out/refcount/unique_ptr_nested.rs
+++ b/tests/unit/out/refcount/unique_ptr_nested.rs
@@ -39,7 +39,19 @@ impl ByteRepr for Inner {
 pub struct Outer {
     pub inner: Value<Option<Value<Inner>>>,
 }
-impl ByteRepr for Outer {}
+impl ByteRepr for Outer {
+    fn byte_size() -> usize {
+        8
+    }
+    fn to_bytes(&self, buf: &mut [u8]) {
+        (*self.inner.borrow()).to_bytes(&mut buf[0..8]);
+    }
+    fn from_bytes(buf: &[u8]) -> Self {
+        Self {
+            inner: Rc::new(RefCell::new(<Option<Value<Inner>>>::from_bytes(&buf[0..8]))),
+        }
+    }
+}
 pub fn main() {
     std::process::exit(main_0());
 }
diff --git a/tests/unit/out/refcount/void_cast.rs b/tests/unit/out/refcount/void_cast.rs
index 0933260f..f8b0af11 100644
--- a/tests/unit/out/refcount/void_cast.rs
+++ b/tests/unit/out/refcount/void_cast.rs
@@ -22,7 +22,19 @@ impl Clone for NonTrivial {
         this
     }
 }
-impl ByteRepr for NonTrivial {}
+impl ByteRepr for NonTrivial {
+    fn byte_size() -> usize {
+        24
+    }
+    fn to_bytes(&self, buf: &mut [u8]) {
+        (*self.data.borrow()).to_bytes(&mut buf[0..24]);
+    }
+    fn from_bytes(buf: &[u8]) -> Self {
+        Self {
+            data: Rc::new(RefCell::new(<Vec<i32>>::from_bytes(&buf[0..24]))),
+        }
+    }
+}
 pub fn unused_ref_param_1(x: Ptr<NonTrivial>) {
     (*x.upgrade().deref()).clone();
 }