diff --git a/include/pocketpy/codeobject.h b/include/pocketpy/codeobject.h
index a136f635..9ad1df12 100644
--- a/include/pocketpy/codeobject.h
+++ b/include/pocketpy/codeobject.h
@@ -128,35 +128,17 @@ struct FuncDecl {
         PyObject* value;        // default value
     };
     CodeObject_ code;           // code object of this function
-    std::vector<int> args;       // indices in co->varnames
-    std::vector<KwArg> kwargs;   // indices in co->varnames
-    int starred_arg;            // index in co->varnames, -1 if no *arg
-    int starred_kwarg;          // index in co->varnames, -1 if no **kwarg
-    bool nested;                // whether this function is nested
-
-    static const int MAX_K2I_CACHE = 16;
-
-    int _keyword_to_index[MAX_K2I_CACHE];   // map from `kwargs[i].key` to `kwargs[i].index`
+    std::vector<int> args;      // indices in co->varnames
+    std::vector<KwArg> 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
 
     Str signature;              // signature of this function
     Str docstring;              // docstring of this function
     bool is_simple;
 
-    FuncDecl(){
-        starred_arg = -1;
-        starred_kwarg = -1;
-        nested = false;
-        for(int i=0; i<MAX_K2I_CACHE; i++) _keyword_to_index[i] = -1;
-        is_simple = false;
-    }
-
-    void add_kwarg_item(int index, StrName key, PyObject* value){
-        kwargs.push_back(KwArg{index, key, value});
-        if(key.index < MAX_K2I_CACHE) _keyword_to_index[key.index] = index;
-    }
-
     int keyword_to_index(StrName key) const{
-        if(key.index < MAX_K2I_CACHE) return _keyword_to_index[key.index];
         for(const KwArg& item: kwargs) if(item.key == key) return item.index;
         return -1;
     }
diff --git a/src/compiler.cpp b/src/compiler.cpp
index e146d8be..36d94219 100644
--- a/src/compiler.cpp
+++ b/src/compiler.cpp
@@ -1037,7 +1037,7 @@ __EAT_DOTS_END:
                     if(value == nullptr){
                         SyntaxError(Str("default argument must be a literal"));
                     }
-                    decl->add_kwarg_item(index, name, value);
+                    decl->kwargs.push_back(FuncDecl::KwArg{index, name, value});
                 } break;
                 case 3:
                     decl->starred_kwarg = index;