diff --git a/src/ast_analyzer.c b/src/ast_analyzer.c
index b1befe597..6fe40a4e5 100644
--- a/src/ast_analyzer.c
+++ b/src/ast_analyzer.c
@@ -19,6 +19,7 @@ typedef struct kxana_context_ {
     int depth;
     int in_catch;
     int in_native;
+    int in_function;
     int class_id;
     int arg_index;
     int anon_arg;
@@ -665,7 +666,7 @@ LOOP_HEAD:;
                 }
                 break;
             }
-            if (is_anon_var(actx, node)) {
+            if (actx->in_function && is_anon_var(actx, node)) {
                 break;
             }
             int enumv = 0;
@@ -1604,6 +1605,8 @@ LOOP_HEAD:;
         enum_map_t enval = kh_init(enum_value);
         kv_push(enum_map_t, actx->enval, enval);
 
+        int in_function = actx->in_function;
+        actx->in_function = 1;
         kx_object_t *class_node = actx->class_node;
         actx->class_node = node;
         int depth = actx->depth;
@@ -1671,6 +1674,7 @@ LOOP_HEAD:;
         kv_remove_last(actx->symbols);
         actx->depth = depth;
         actx->class_node = class_node;
+        actx->in_function = in_function;
 
         kh_destroy(enum_value, enval);
         kv_pop(actx->enval);
@@ -1727,6 +1731,8 @@ LOOP_HEAD:;
         enum_map_t enval = kh_init(enum_value);
         kv_push(enum_map_t, actx->enval, enval);
 
+        int in_function = actx->in_function;
+        actx->in_function = 1;
         if (node->type == KXST_NATIVE) {
             actx->in_native = 1;
             node->var_type = KX_NFNC_T;
@@ -1785,6 +1791,7 @@ LOOP_HEAD:;
         kv_remove_last(actx->symbols);
         actx->depth = depth;
         actx->in_native = 0;
+        actx->in_function = in_function;
 
         kh_destroy(enum_value, enval);
         kv_pop(actx->enval);
diff --git a/src/optimizer/opt_cfold.c b/src/optimizer/opt_cfold.c
index affaf4385..6fd5d062e 100644
--- a/src/optimizer/opt_cfold.c
+++ b/src/optimizer/opt_cfold.c
@@ -21,6 +21,7 @@ typedef struct folding_context_ {
     int anon_check;
     int anon_arg;
     int exprlist_r2l;
+    int in_function;
     int in_case_when;
 } folding_context_t;
 
@@ -53,7 +54,7 @@ static void opt_ast_constant_folding_impl(kx_context_t *ctx, kx_object_t *node,
         break;
 
     case KXOP_VAR: {
-        if (cctx->anon_check) {
+        if (cctx->in_function && cctx->anon_check) {
             const char *name = node->value.s;
             if (!cctx->in_case_when && name && name[0] == '_' && name[1] == 0) {
                 node->lexical = 0;
@@ -438,22 +439,28 @@ static void opt_ast_constant_folding_impl(kx_context_t *ctx, kx_object_t *node,
         break;
     case KXST_SYSCLASS:
     case KXST_CLASS: {    /* s: name, lhs: arglist, rhs: block: ex: expr (inherit) */
+        int in_function = cctx->in_function;
+        cctx->in_function = 1;
         int anon_arg = cctx->anon_arg;
         cctx->anon_arg = 0;
         opt_ast_constant_folding_impl(ctx, node->lhs, cctx);
         opt_ast_constant_folding_impl(ctx, node->rhs, cctx);
         opt_ast_constant_folding_impl(ctx, node->ex, cctx);
         cctx->anon_arg = anon_arg;
+        cctx->in_function = in_function;
         break;
     }
     case KXST_COROUTINE:  /* s: name, lhs: arglist, rhs: block: optional: public/private/protected */
     case KXST_FUNCTION: /* s: name, lhs: arglist, rhs: block: optional: public/private/protected */
     case KXST_NATIVE: { /* s: name, lhs: arglist, rhs: block: ret_type: return type */
+        int in_function = cctx->in_function;
+        cctx->in_function = 1;
         int anon_arg = cctx->anon_arg;
         cctx->anon_arg = 0;
         opt_ast_constant_folding_impl(ctx, node->lhs, cctx);
         opt_ast_constant_folding_impl(ctx, node->rhs, cctx);
         cctx->anon_arg = anon_arg;
+        cctx->in_function = in_function;
         break;
     }
     default: