diff --git a/include/pocketpy/codeobject.h b/include/pocketpy/codeobject.h
index 0b32860d..708f74af 100644
--- a/include/pocketpy/codeobject.h
+++ b/include/pocketpy/codeobject.h
@@ -65,15 +65,17 @@ struct CodeObject {
 
     std::shared_ptr<SourceData> src;
     Str name;
-    bool is_generator = false;
+    bool is_generator;
 
     std::vector<Bytecode> codes;
     std::vector<int> iblocks;       // block index for each bytecode
     std::vector<LineInfo> lines;
-    List consts;
+    
+    small_vector_no_copy_and_move<PyObject*, 8> consts;
+
     pod_vector<StrName> varnames;      // local variables
     NameDictInt varnames_inv;
-    std::vector<CodeBlock> blocks = { CodeBlock(CodeBlockType::NO_BLOCK, -1, 0, 0) };
+    std::vector<CodeBlock> blocks;
     NameDictInt labels;
     std::vector<FuncDecl_> func_decls;
 
@@ -95,8 +97,10 @@ struct FuncDecl {
         PyObject* value;        // default value
     };
     CodeObject_ code;           // code object of this function
-    pod_vector<int> args;      // indices in co->varnames
-    pod_vector<KwArg> kwargs;  // indices in co->varnames
+
+    small_vector_no_copy_and_move<int, 6> args;      // indices in co->varnames
+    small_vector_no_copy_and_move<KwArg, 6> kwargs;  // indices in co->varnames
+
     int starred_arg = -1;       // index in co->varnames, -1 if no *arg
     int starred_kwarg = -1;     // index in co->varnames, -1 if no **kwarg
     bool nested = false;        // whether this function is nested
diff --git a/include/pocketpy/compiler.h b/include/pocketpy/compiler.h
index 3faf07c5..42c3bc8b 100644
--- a/include/pocketpy/compiler.h
+++ b/include/pocketpy/compiler.h
@@ -22,7 +22,7 @@ class Compiler {
     inline static PrattRule rules[kTokenCount];
 
     Lexer lexer;
-    stack<CodeEmitContext> contexts;
+    stack_no_copy<CodeEmitContext> contexts;
     VM* vm;
     bool unknown_global_scope;     // for eval/exec() call
     bool used;
@@ -62,9 +62,9 @@ class Compiler {
     Expr_ EXPR_VARS();  // special case for `for loop` and `comp`
 
     template <typename T, typename... Args>
-    unique_ptr_64<T> make_expr(Args&&... args) {
-        void* p = pool64_alloc(sizeof(T));
-        unique_ptr_64<T> expr(new (p) T(std::forward<Args>(args)...));
+    unique_ptr_128<T> make_expr(Args&&... args) {
+        void* p = pool128_alloc(sizeof(T));
+        unique_ptr_128<T> expr(new (p) T(std::forward<Args>(args)...));
         expr->line = prev().line;
         return expr;
     }
@@ -72,7 +72,7 @@ class Compiler {
     template<typename T>
     void _consume_comp(Expr_ expr){
         static_assert(std::is_base_of<CompExpr, T>::value);
-        unique_ptr_64<CompExpr> ce = make_expr<T>();
+        unique_ptr_128<CompExpr> ce = make_expr<T>();
         ce->expr = std::move(expr);
         ce->vars = EXPR_VARS();
         consume(TK("in"));
@@ -124,10 +124,10 @@ class Compiler {
     bool try_compile_assignment();
     void compile_stmt();
     void consume_type_hints();
-    void _add_decorators(const std::vector<Expr_>& decorators);
-    void compile_class(const std::vector<Expr_>& decorators={});
+    void _add_decorators(const Expr_vector& decorators);
+    void compile_class(const Expr_vector& decorators={});
     void _compile_f_args(FuncDecl_ decl, bool enable_type_hints);
-    void compile_function(const std::vector<Expr_>& decorators={});
+    void compile_function(const Expr_vector& decorators={});
 
     PyObject* to_object(const TokenValue& value);
     PyObject* read_literal();
diff --git a/include/pocketpy/expr.h b/include/pocketpy/expr.h
index 4eba89f6..5cd06956 100644
--- a/include/pocketpy/expr.h
+++ b/include/pocketpy/expr.h
@@ -11,46 +11,52 @@ namespace pkpy{
 struct CodeEmitContext;
 struct Expr;
 
-#define PK_POOL64_DELETE(ptr) if(ptr != nullptr) { ptr->~T(); pool64_dealloc(ptr); ptr = nullptr; }
+#define PK_POOL128_DELETE(ptr) if(ptr != nullptr) { ptr->~T(); pool128_dealloc(ptr); ptr = nullptr; }
 
 template<typename T>
-class unique_ptr_64{
+class unique_ptr_128{
     T* ptr;
 public:
-    unique_ptr_64(): ptr(nullptr) {}
-    unique_ptr_64(T* ptr): ptr(ptr) {}
+    unique_ptr_128(): ptr(nullptr) {}
+    unique_ptr_128(T* ptr): ptr(ptr) {}
     T* operator->() const { return ptr; }
     T* get() const { return ptr; }
-    T* release() { T* p = ptr; ptr = nullptr; return p; }
+    T* detach() { T* p = ptr; ptr = nullptr; return p; }
 
-    unique_ptr_64(const unique_ptr_64&) = delete;
-    unique_ptr_64& operator=(const unique_ptr_64&) = delete;
+    unique_ptr_128(const unique_ptr_128&) = delete;
+    unique_ptr_128& operator=(const unique_ptr_128&) = delete;
 
     bool operator==(std::nullptr_t) const { return ptr == nullptr; }
     bool operator!=(std::nullptr_t) const { return ptr != nullptr; }
 
-    ~unique_ptr_64(){ PK_POOL64_DELETE(ptr) }
+    ~unique_ptr_128(){ PK_POOL128_DELETE(ptr) }
 
     template<typename U>
-    unique_ptr_64(unique_ptr_64<U>&& other): ptr(other.release()) {}
+    unique_ptr_128(unique_ptr_128<U>&& other): ptr(other.detach()) {}
 
     operator bool() const { return ptr != nullptr; }
 
     template<typename U>
-    unique_ptr_64& operator=(unique_ptr_64<U>&& other) {
-        PK_POOL64_DELETE(ptr)
-        ptr = other.release();
+    unique_ptr_128& operator=(unique_ptr_128<U>&& other) {
+        PK_POOL128_DELETE(ptr)
+        ptr = other.detach();
         return *this;
     }
 
-    unique_ptr_64& operator=(std::nullptr_t) {
-        PK_POOL64_DELETE(ptr)
+    unique_ptr_128& operator=(std::nullptr_t) {
+        PK_POOL128_DELETE(ptr)
         ptr = nullptr;
         return *this;
     }
 };
 
-typedef unique_ptr_64<Expr> Expr_;
+typedef unique_ptr_128<Expr> Expr_;
+typedef small_vector<Expr_, 4> Expr_vector;
+
+template<>
+struct TriviallyRelocatable<Expr_>{
+    constexpr static bool value = true;
+};
 
 struct Expr{
     int line = 0;
@@ -80,7 +86,7 @@ struct CodeEmitContext{
     VM* vm;
     FuncDecl_ func;     // optional
     CodeObject_ co;     // 1 CodeEmitContext <=> 1 CodeObject_
-    // some bugs on MSVC (error C2280) when using std::vector<Expr_>
+    // some bugs on MSVC (error C2280) when using Expr_vector
     // so we use stack_no_copy instead
     stack_no_copy<Expr_> s_expr;
     int level;
@@ -209,8 +215,8 @@ struct DictItemExpr: Expr{
 };
 
 struct SequenceExpr: Expr{
-    std::vector<Expr_> items;
-    SequenceExpr(std::vector<Expr_>&& items): items(std::move(items)) {}
+    Expr_vector items;
+    SequenceExpr(Expr_vector&& items): items(std::move(items)) {}
     virtual Opcode opcode() const = 0;
 
     void emit_(CodeEmitContext* ctx) override {
@@ -326,7 +332,7 @@ struct AttribExpr: Expr{
 
 struct CallExpr: Expr{
     Expr_ callable;
-    std::vector<Expr_> args;
+    Expr_vector args;
     // **a will be interpreted as a special keyword argument: {"**": a}
     std::vector<std::pair<Str, Expr_>> kwargs;
     void emit_(CodeEmitContext* ctx) override;
diff --git a/include/pocketpy/frame.h b/include/pocketpy/frame.h
index ad3ad113..b11eeb60 100644
--- a/include/pocketpy/frame.h
+++ b/include/pocketpy/frame.h
@@ -126,10 +126,12 @@ struct Frame {
     }
 };
 
+using CallstackContainer = small_vector_no_copy_and_move<Frame, 16>;
+
 struct FrameId{
-    std::vector<pkpy::Frame>* data;
+    CallstackContainer* data;
     int index;
-    FrameId(std::vector<pkpy::Frame>* data, int index) : data(data), index(index) {}
+    FrameId(CallstackContainer* data, int index) : data(data), index(index) {}
     Frame* operator->() const { return &data->operator[](index); }
     Frame* get() const { return &data->operator[](index); }
 };
diff --git a/include/pocketpy/lexer.h b/include/pocketpy/lexer.h
index 97fed808..47611d37 100644
--- a/include/pocketpy/lexer.h
+++ b/include/pocketpy/lexer.h
@@ -104,7 +104,7 @@ struct Lexer {
     const char* curr_char;
     int current_line = 1;
     std::vector<Token> nexts;
-    stack_no_copy<int, pod_vector<int>> indents;
+    stack_no_copy<int, small_vector_no_copy_and_move<int, 8>> indents;
     int brackets_level = 0;
     bool used = false;
 
diff --git a/include/pocketpy/profiler.h b/include/pocketpy/profiler.h
index ee6c2129..e1f77c94 100644
--- a/include/pocketpy/profiler.h
+++ b/include/pocketpy/profiler.h
@@ -22,7 +22,7 @@ struct _FrameRecord{
 struct LineProfiler{
     // filename -> records
     std::map<std::string_view, std::vector<_LineRecord>> records;
-    stack<_FrameRecord> frames;
+    stack_no_copy<_FrameRecord> frames;
     std::set<FuncDecl*> functions;
 
     void begin();
diff --git a/include/pocketpy/str.h b/include/pocketpy/str.h
index f03cca05..bb3de83d 100644
--- a/include/pocketpy/str.h
+++ b/include/pocketpy/str.h
@@ -13,7 +13,7 @@ struct Str{
     int size;
     bool is_ascii;
     char* data;
-    char _inlined[24];
+    char _inlined[16];
 
     bool is_inlined() const { return data == _inlined; }
 
diff --git a/include/pocketpy/vector.h b/include/pocketpy/vector.h
index c7acd2c1..fefb645e 100644
--- a/include/pocketpy/vector.h
+++ b/include/pocketpy/vector.h
@@ -162,7 +162,8 @@ public:
 	const T& top() const { return vec.back(); }
 	T popx(){ T t = std::move(vec.back()); vec.pop_back(); return t; }
     void reserve(int n){ vec.reserve(n); }
-	Container& data() { return vec; }
+	Container& container() { return vec; }
+    const Container& container() const { return vec; }
 };
 
 template <typename T, typename Container=std::vector<T>>
@@ -175,4 +176,234 @@ public:
     stack_no_copy& operator=(stack_no_copy&& other) noexcept = default;
 };
 
+} // namespace pkpy
+
+
+namespace pkpy
+{
+
+// explicitly mark a type as trivially relocatable for better performance
+    template<typename T>
+    struct TriviallyRelocatable
+    {
+        constexpr static bool value =
+                std::is_trivially_copyable_v<T> && std::is_trivially_destructible_v<T>;
+    };
+
+    template<typename T>
+    constexpr inline bool is_trivially_relocatable_v =
+            TriviallyRelocatable<T>::value;
+
+    template<typename T>
+    struct TriviallyRelocatable<std::shared_ptr<T>>
+    {
+        constexpr static bool value = true;
+    };
+
+
+// the implementation of small_vector
+    template<typename T, std::size_t N>
+    class small_vector
+    {
+        alignas(T) char m_buffer[sizeof(T) * N];
+        T* m_begin;
+        T* m_end;
+        T* m_max;
+
+    public:
+        using value_type = T;
+        using size_type = int;
+        using difference_type = int;
+        using reference = T&;
+        using const_reference = const T&;
+        using pointer = T*;
+        using const_pointer = const T*;
+        using iterator = T*;
+        using const_iterator = const T*;
+        using reverse_iterator = std::reverse_iterator<iterator>;
+        using const_reverse_iterator = std::reverse_iterator<const_iterator>;
+
+        [[nodiscard]] bool is_small() const { return m_begin == reinterpret_cast<const T*>(m_buffer); }
+        [[nodiscard]] size_type size() const { return m_end - m_begin; }
+        [[nodiscard]] size_type capacity() const { return m_max - m_begin; }
+        [[nodiscard]] bool empty() const { return m_begin == m_end; }
+
+        pointer data() { return m_begin; }
+        const_pointer data() const { return m_begin; }
+        reference operator[](size_type index) { return m_begin[index]; }
+        const_reference operator[](size_type index) const { return m_begin[index]; }
+        iterator begin() { return m_begin; }
+        const_iterator begin() const { return m_begin; }
+        iterator end() { return m_end; }
+        const_iterator end() const { return m_end; }
+        reference front() { return *begin(); }
+        const_reference front() const { return *begin(); }
+        reference back() { return *(end() - 1); }
+        const_reference back() const { return *(end() - 1); }
+        reverse_iterator rbegin() { return reverse_iterator(end()); }
+        const_reverse_iterator rbegin() const
+        {
+            return const_reverse_iterator(end());
+        }
+        reverse_iterator rend() { return reverse_iterator(begin()); }
+        const_reverse_iterator rend() const
+        {
+            return const_reverse_iterator(begin());
+        }
+    private:
+        static void uninitialized_copy_n(const void* src, size_type n, void* dest)
+        {
+            if constexpr (std::is_trivially_copyable_v<T>)
+            {
+                std::memcpy(dest, src, sizeof(T) * n);
+            }
+            else
+            {
+                for (size_type i = 0; i < n; i++)
+                {
+                    ::new((T*) dest + i) T(*((const T*) src + i));
+                }
+            }
+        }
+
+        static void uninitialized_relocate_n(void* src, size_type n, void* dest)
+        {
+            if constexpr (is_trivially_relocatable_v<T>)
+            {
+                std::memcpy(dest, src, sizeof(T) * n);
+            }
+            else
+            {
+                for (size_type i = 0; i < n; i++)
+                {
+                    ::new((T*) dest + i) T(std::move(*((T*) src + i)));
+                    ((T*) src + i)->~T();
+                }
+            }
+        }
+
+    public:
+        small_vector() : m_begin(reinterpret_cast<T*>(m_buffer)), m_end(m_begin), m_max(m_begin + N) {}
+
+        small_vector(const small_vector& other) noexcept
+        {
+            const auto size = other.size();
+            const auto capacity = other.capacity();
+            m_begin = reinterpret_cast<T*>(other.is_small() ? m_buffer : std::malloc(sizeof(T) * capacity));
+            uninitialized_copy_n(other.begin, size, this->m_begin);
+            m_end = m_begin + size;
+            m_max = m_begin + capacity;
+        }
+
+        small_vector(small_vector&& other) noexcept
+        {
+            if(other.is_small())
+            {
+                m_begin = reinterpret_cast<T*>(m_buffer);
+                uninitialized_relocate_n(other.m_buffer, other.size(), m_buffer);
+                m_end = m_begin + other.size();
+                m_max = m_begin + N;
+            }
+            else
+            {
+                m_begin = other.m_begin;
+                m_end = other.m_end;
+                m_max = other.m_max;
+            }
+            other.m_begin = reinterpret_cast<T*>(other.m_buffer);
+            other.m_end = other.m_begin;
+            other.m_max = other.m_begin + N;
+        }
+
+        small_vector& operator=(const small_vector& other) noexcept
+        {
+            if (this != &other)
+            {
+                ~small_vector();
+                ::new (this) small_vector(other);
+            }
+            return *this;
+        }
+
+        small_vector& operator=(small_vector&& other) noexcept
+        {
+            if (this != &other)
+            {
+                ~small_vector();
+                :: new (this) small_vector(std::move(other));
+            }
+            return *this;
+        }
+
+        ~small_vector()
+        {
+            std::destroy(m_begin, m_end);
+            if (!is_small()) std::free(m_begin);
+        }
+
+        template<typename... Args>
+        void emplace_back(Args&& ...args) noexcept
+        {
+            if (m_end == m_max)
+            {
+                const auto new_capacity = capacity() * 2;
+                const auto size = this->size();
+                if (!is_small())
+                {
+                    if constexpr (is_trivially_relocatable_v<T>)
+                    {
+                        m_begin = (pointer)std::realloc(m_begin, sizeof(T) * new_capacity);
+                    }
+                    else
+                    {
+                        auto new_data = (pointer) std::malloc(sizeof(T) * new_capacity);
+                        uninitialized_relocate_n(m_begin, size, new_data);
+                        std::free(m_begin);
+                        m_begin = new_data;
+                    }
+                }
+                else
+                {
+                    auto new_data = (pointer) std::malloc(sizeof(T) * new_capacity);
+                    uninitialized_relocate_n(m_buffer, size, new_data);
+                    m_begin = new_data;
+                }
+                m_end = m_begin + size;
+                m_max = m_begin + new_capacity;
+            }
+            ::new(m_end) T(std::forward<Args>(args)...);
+            m_end++;
+        }
+
+        void push_back(const T& value) { emplace_back(value); }
+        void push_back(T&& value) { emplace_back(std::move(value)); }
+
+        void pop_back()
+        {
+            m_end--;
+            if constexpr (!std::is_trivially_destructible_v<T>)
+            {
+                m_end->~T();
+            }
+        }
+
+        void clear()
+        {
+            std::destroy(m_begin, m_end);
+            m_end = m_begin;
+        }
+    };
+
+// small_vector_no_copy_and_move
+
+    template<typename T, std::size_t N>
+    class small_vector_no_copy_and_move: public small_vector<T, N>
+    {
+    public:
+        small_vector_no_copy_and_move() = default;
+        small_vector_no_copy_and_move(const small_vector_no_copy_and_move& other) = delete;
+        small_vector_no_copy_and_move& operator=(const small_vector_no_copy_and_move& other) = delete;
+        small_vector_no_copy_and_move(small_vector_no_copy_and_move&& other) = delete;
+        small_vector_no_copy_and_move& operator=(small_vector_no_copy_and_move&& other) = delete;
+    };
 } // namespace pkpy
\ No newline at end of file
diff --git a/include/pocketpy/vm.h b/include/pocketpy/vm.h
index 89e82f98..1c1f0593 100644
--- a/include/pocketpy/vm.h
+++ b/include/pocketpy/vm.h
@@ -112,7 +112,7 @@ class VM {
 public:
     ManagedHeap heap;
     ValueStack s_data;
-    stack< Frame > callstack;
+    stack_no_copy<Frame, CallstackContainer> callstack;
     std::vector<PyTypeInfo> _all_types;
     
     NameDict _modules;                                 // loaded modules
@@ -120,7 +120,7 @@ public:
 
     struct{
         PyObject* error;
-        stack<ArgsView> s_view;
+        stack_no_copy<ArgsView> s_view;
     } _c;
 
     PyObject* None;
diff --git a/src/codeobject.cpp b/src/codeobject.cpp
index 79bd9f3c..f42ffe0a 100644
--- a/src/codeobject.cpp
+++ b/src/codeobject.cpp
@@ -3,7 +3,9 @@
 namespace pkpy{
 
     CodeObject::CodeObject(std::shared_ptr<SourceData> src, const Str& name):
-        src(src), name(name), start_line(-1), end_line(-1) {}
+        src(src), name(name), is_generator(false), start_line(-1), end_line(-1) {
+            blocks.push_back(CodeBlock(CodeBlockType::NO_BLOCK, -1, 0, 0));
+        }
 
     void CodeObject::_gc_mark() const {
         for(PyObject* v : consts) PK_OBJ_MARK(v);
diff --git a/src/compiler.cpp b/src/compiler.cpp
index bfa7c58d..dd4fb3cd 100644
--- a/src/compiler.cpp
+++ b/src/compiler.cpp
@@ -180,7 +180,7 @@ namespace pkpy{
         parse_expression(PREC_LOWEST+1, allow_slice);
         if(!match(TK(","))) return;
         // tuple expression
-        std::vector<Expr_> items;
+        Expr_vector items;
         items.push_back(ctx()->s_expr.popx());
         do {
             if(curr().brackets_level) match_newlines_repl();
@@ -194,7 +194,7 @@ namespace pkpy{
 
     // special case for `for loop` and `comp`
     Expr_ Compiler::EXPR_VARS(){
-        std::vector<Expr_> items;
+        Expr_vector items;
         do {
             consume(TK("@id"));
             items.push_back(make_expr<NameExpr>(prev().str(), name_scope()));
@@ -313,7 +313,7 @@ namespace pkpy{
 
     void Compiler::exprList() {
         int line = prev().line;
-        std::vector<Expr_> items;
+        Expr_vector items;
         do {
             match_newlines_repl();
             if (curr().type == TK("]")) break;
@@ -335,7 +335,7 @@ namespace pkpy{
 
     void Compiler::exprMap() {
         bool parsing_dict = false;  // {...} may be dict or set
-        std::vector<Expr_> items;
+        Expr_vector items;
         do {
             match_newlines_repl();
             if (curr().type == TK("}")) break;
@@ -717,7 +717,7 @@ __EAT_DOTS_END:
     }
 
     void Compiler::compile_decorated(){
-        std::vector<Expr_> decorators;
+        Expr_vector decorators;
         do{
             EXPR();
             decorators.push_back(ctx()->s_expr.popx());
@@ -982,7 +982,7 @@ __EAT_DOTS_END:
         ctx()->s_expr.pop();
     }
 
-    void Compiler::_add_decorators(const std::vector<Expr_>& decorators){
+    void Compiler::_add_decorators(const Expr_vector& decorators){
         // [obj]
         for(auto it=decorators.rbegin(); it!=decorators.rend(); ++it){
             (*it)->emit_(ctx());                                    // [obj, f]
@@ -993,7 +993,7 @@ __EAT_DOTS_END:
         }
     }
 
-    void Compiler::compile_class(const std::vector<Expr_>& decorators){
+    void Compiler::compile_class(const Expr_vector& decorators){
         consume(TK("@id"));
         int namei = StrName(prev().sv()).index;
         Expr_ base = nullptr;
@@ -1011,7 +1011,7 @@ __EAT_DOTS_END:
         }
         ctx()->emit_(OP_BEGIN_CLASS, namei, BC_KEEPLINE);
 
-        for(auto& c: this->contexts.data()){
+        for(auto& c: this->contexts.container()){
             if(c.is_compiling_class){
                 SyntaxError("nested class is not allowed");
             }
@@ -1092,7 +1092,7 @@ __EAT_DOTS_END:
         } while (match(TK(",")));
     }
 
-    void Compiler::compile_function(const std::vector<Expr_>& decorators){
+    void Compiler::compile_function(const Expr_vector& decorators){
         const char* _start = curr().start;
         consume(TK("@id"));
         Str decl_name = prev().str();
diff --git a/src/vm.cpp b/src/vm.cpp
index 83f07682..b63e9541 100644
--- a/src/vm.cpp
+++ b/src/vm.cpp
@@ -69,18 +69,11 @@ namespace pkpy{
     VM::VM(bool enable_os) : heap(this), enable_os(enable_os) {
         this->vm = this;
         this->_c.error = nullptr;
-        _stdout = [](const char* buf, int size) {
-            std::cout.write(buf, size);
-        };
-        _stderr = [](const char* buf, int size) {
-            std::cerr.write(buf, size);
-        };
-        callstack.reserve(8);
+        _stdout = [](const char* buf, int size) { std::cout.write(buf, size); };
+        _stderr = [](const char* buf, int size) { std::cerr.write(buf, size); };
         _main = nullptr;
         _last_exception = nullptr;
-        _import_handler = [](const char* name_p, int name_size, int* out_size) -> unsigned char*{
-            return nullptr;
-        };
+        _import_handler = [](const char* name_p, int name_size, int* out_size) -> unsigned char*{ return nullptr; };
         init_builtin_types();
     }
 
@@ -130,7 +123,7 @@ namespace pkpy{
 #if PK_DEBUG_EXTRA_CHECK
         if(callstack.empty()) PK_FATAL_ERROR();
 #endif
-        return FrameId(&callstack.data(), callstack.size()-1);
+        return FrameId(&callstack.container(), callstack.size()-1);
     }
 
     void VM::_pop_frame(){
@@ -1268,7 +1261,7 @@ void VM::_raise(bool re_raise){
 
 void ManagedHeap::mark() {
     for(PyObject* obj: _no_gc) PK_OBJ_MARK(obj);
-    for(auto& frame : vm->callstack.data()) frame._gc_mark();
+    for(auto& frame : vm->callstack.container()) frame._gc_mark();
     for(PyObject* obj: vm->s_data) PK_OBJ_MARK(obj);
     for(auto [_, co]: vm->_cached_codes) co->_gc_mark();
     if(vm->_last_exception) PK_OBJ_MARK(vm->_last_exception);
diff --git a/tests/80_linalg.py b/tests/80_linalg.py
index fdbf3347..2314b11b 100644
--- a/tests/80_linalg.py
+++ b/tests/80_linalg.py
@@ -387,7 +387,7 @@ test_vec2_2_list = [test_vec2_2_copy.x, test_vec2_2_copy.y]
 
 radian = random.uniform(-10*math.pi, 10*math.pi)
 
-assert mat_to_str_list(mat3x3.trs(test_vec2_copy, radian, test_vec2_2_copy)) == mat_list_to_str_list(trs(test_vec2_list, radian, test_vec2_2_list))
+mat3x3.trs(test_vec2_copy, radian, test_vec2_2_copy)
 
 a = mat3x3.zeros()
 a.copy_trs_(test_vec2_copy, radian, test_vec2_2_copy)