diff --git a/include/pocketpy/codeobject.h b/include/pocketpy/codeobject.h
index 6e06731e..db3eec05 100644
--- a/include/pocketpy/codeobject.h
+++ b/include/pocketpy/codeobject.h
@@ -65,7 +65,7 @@ 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
diff --git a/src/codeobject.cpp b/src/codeobject.cpp
index ef156c18..f42ffe0a 100644
--- a/src/codeobject.cpp
+++ b/src/codeobject.cpp
@@ -3,7 +3,7 @@
 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));
         }