diff --git a/src/codeobject.h b/src/codeobject.h
index 1123bfca..55df6123 100644
--- a/src/codeobject.h
+++ b/src/codeobject.h
@@ -65,8 +65,6 @@ struct CodeObject {
     NameDictInt labels;
     std::vector<FuncDecl_> func_decls;
 
-    void optimize(VM* vm);
-
     void _gc_mark() const {
         for(PyObject* v : consts) OBJ_MARK(v);
         for(auto& decl: func_decls) decl->_gc_mark();
diff --git a/src/common.h b/src/common.h
index 2e75afec..898a4b6d 100644
--- a/src/common.h
+++ b/src/common.h
@@ -161,7 +161,4 @@ inline PyObject* const PY_BEGIN_CALL = (PyObject*)0b010011;
 inline PyObject* const PY_OP_CALL = (PyObject*)0b100011;
 inline PyObject* const PY_OP_YIELD = (PyObject*)0b110011;
 
-struct Expr;
-typedef std::unique_ptr<Expr> Expr_;
-
 } // namespace pkpy
\ No newline at end of file
diff --git a/src/compiler.h b/src/compiler.h
index 02b69f4a..5a2c77ad 100644
--- a/src/compiler.h
+++ b/src/compiler.h
@@ -67,7 +67,7 @@ class Compiler {
         // however, this is buggy...since there may be a jump to the end (out of bound) even if the last opcode is a return
         ctx()->emit(OP_LOAD_NONE, BC_NOARG, BC_KEEPLINE);
         ctx()->emit(OP_RETURN_VALUE, BC_NOARG, BC_KEEPLINE);
-        ctx()->co->optimize(vm);
+        // ctx()->co->optimize(vm);
         if(ctx()->co->varnames.size() > PK_MAX_CO_VARNAMES){
             SyntaxError("maximum number of local variables exceeded");
         }
diff --git a/src/expr.h b/src/expr.h
index 3a3e31f7..1a249b9d 100644
--- a/src/expr.h
+++ b/src/expr.h
@@ -6,11 +6,12 @@
 #include "error.h"
 #include "ceval.h"
 #include "str.h"
-#include <algorithm>
 
 namespace pkpy{
 
 struct CodeEmitContext;
+struct Expr;
+typedef std::unique_ptr<Expr> Expr_;
 
 struct Expr{
     int line = 0;
diff --git a/src/linalg.h b/src/linalg.h
index a2fe1b3c..5161a9b1 100644
--- a/src/linalg.h
+++ b/src/linalg.h
@@ -204,14 +204,6 @@ struct Mat3x3{
     }
 
     /*************** affine transformations ***************/
-    static Mat3x3 rotate(float radian){
-        float cr = cosf(radian);
-        float sr = sinf(radian);
-        return Mat3x3(cr,   -sr,  0.0f,
-                      sr,   cr,   0.0f,
-                      0.0f, 0.0f, 1.0f);
-    }
-
     static Mat3x3 trs(Vec2 t, float radian, Vec2 s){
         float cr = cosf(radian);
         float sr = sinf(radian);
@@ -350,7 +342,12 @@ struct PyVec2: Vec2 {
         vm->bind_method<1>(type, "rotate", [](VM* vm, ArgsView args){
             Vec2 self = _CAST(PyVec2&, args[0]);
             float radian = vm->num_to_float(args[1]);
-            self = Mat3x3::rotate(radian).transform_vector(self);
+            float cr = cosf(radian);
+            float sr = sinf(radian);
+            Mat3x3 rotate(cr,   -sr,  0.0f,
+                          sr,   cr,   0.0f,
+                          0.0f, 0.0f, 1.0f);
+            self = rotate.transform_vector(self);
             return VAR(self);
         });
 
diff --git a/src/vm.h b/src/vm.h
index e48d71d8..374ec315 100644
--- a/src/vm.h
+++ b/src/vm.h
@@ -591,7 +591,7 @@ public:
 
 inline PyObject* NativeFunc::operator()(VM* vm, ArgsView args) const{
     int args_size = args.size() - (int)method;  // remove self
-    if(argc != -1 && args_size != argc) {
+    if(args_size != argc && argc != -1) {
         vm->TypeError(fmt("expected ", argc, " arguments, but got ", args_size));
     }
 #if DEBUG_EXTRA_CHECK
@@ -600,12 +600,6 @@ inline PyObject* NativeFunc::operator()(VM* vm, ArgsView args) const{
     return f(vm, args);
 }
 
-inline void CodeObject::optimize(VM* vm){
-    // uint32_t base_n = (uint32_t)(names.size() / kLocalsLoadFactor + 0.5);
-    // perfect_locals_capacity = std::max(find_next_capacity(base_n), NameDict::__Capacity);
-    // perfect_hash_seed = find_perfect_hash_seed(perfect_locals_capacity, names);
-}
-
 DEF_NATIVE_2(Str, tp_str)
 DEF_NATIVE_2(List, tp_list)
 DEF_NATIVE_2(Tuple, tp_tuple)