3 files changed, 4 insertions, 3 deletions
diff --git a/compile.c b/compile.c
index c3afd6c121..04a32556f2 100644
--- a/compile.c
+++ b/compile.c
@@ -4113,7 +4113,7 @@ static int
 defined_expr0(rb_iseq_t *iseq, LINK_ANCHOR *const ret,
 	      const NODE *const node, LABEL **lfinish, VALUE needstr)
 {
-    enum defined_type expr_type = 0;
+    enum defined_type expr_type = DEFINED_NOT_DEFINED;
     enum node_type type;
 
     switch (type = nd_type(node)) {
diff --git a/iseq.h b/iseq.h
index 283f5dcdf4..0c316e2cb2 100644
--- a/iseq.h
+++ b/iseq.h
@@ -276,6 +276,7 @@ struct iseq_compile_data_storage {
 /* defined? */
 
 enum defined_type {
+    DEFINED_NOT_DEFINED,
     DEFINED_NIL = 1,
     DEFINED_IVAR,
     DEFINED_LVAR,
diff --git a/vm_insnhelper.c b/vm_insnhelper.c
index 1327050b2d..8b9bdeb98e 100644
--- a/vm_insnhelper.c
+++ b/vm_insnhelper.c
@@ -2809,7 +2809,7 @@ check_respond_to_missing(VALUE obj, VALUE v)
 	return DEFINED_METHOD;
     }
     else {
-	return 0;
+	return DEFINED_NOT_DEFINED;
     }
 }
 
@@ -2817,7 +2817,7 @@ static VALUE
 vm_defined(rb_execution_context_t *ec, rb_control_frame_t *reg_cfp, rb_num_t op_type, VALUE obj, VALUE needstr, VALUE v)
 {
     VALUE klass;
-    enum defined_type expr_type = 0;
+    enum defined_type expr_type = DEFINED_NOT_DEFINED;
     enum defined_type type = (enum defined_type)op_type;
 
     switch (type) {