diff --git a/cont.c b/cont.c
index 408db21a6d..0f68a99315 100644
--- a/cont.c
+++ b/cont.c
@@ -175,7 +175,7 @@ struct rb_fiber_struct {
     rb_context_t cont;
     VALUE first_proc;
     struct rb_fiber_struct *prev;
-    BITFIELD(enum fiber_status) status : 2;
+    BITFIELD(enum fiber_status, status, 2);
     /* If a fiber invokes "transfer",
      * then this fiber can't "resume" any more after that.
      * You shouldn't mix "transfer" and "resume".
diff --git a/internal.h b/internal.h
index 20df1453e2..de62de1029 100644
--- a/internal.h
+++ b/internal.h
@@ -2144,14 +2144,14 @@ rb_obj_builtin_type(VALUE obj)
 /*
  * For declaring bitfields out of non-unsigned int types:
  *   struct date {
- *      BITFIELD(enum months) month:4;
+ *      BITFIELD(enum months, month, 4);
  *      ...
  *   };
  */
 #if defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L)
-# define BITFIELD(type) type
+# define BITFIELD(type, name, size) type name : size
 #else
-# define BITFIELD(type) unsigned int
+# define BITFIELD(type, name, size) unsigned int name : size
 #endif
 
 #if defined(_MSC_VER)
diff --git a/method.h b/method.h
index 9e0f5e7c47..f6222ca4ae 100644
--- a/method.h
+++ b/method.h
@@ -33,7 +33,7 @@ typedef enum {
 } rb_method_visibility_t;
 
 typedef struct rb_scope_visi_struct {
-    BITFIELD(rb_method_visibility_t) method_visi : 3;
+    BITFIELD(rb_method_visibility_t, method_visi, 3);
     unsigned int module_func : 1;
 } rb_scope_visibility_t;
 
@@ -155,7 +155,7 @@ enum method_optimized_type {
 };
 
 PACKED_STRUCT_UNALIGNED(struct rb_method_definition_struct {
-    BITFIELD(rb_method_type_t) type : VM_METHOD_TYPE_MINIMUM_BITS;
+    BITFIELD(rb_method_type_t, type, VM_METHOD_TYPE_MINIMUM_BITS);
     int alias_count : 28;
     int complemented_count : 28;
 
diff --git a/vm_core.h b/vm_core.h
index b936b0352b..1e27e7f839 100644
--- a/vm_core.h
+++ b/vm_core.h
@@ -879,7 +879,7 @@ typedef struct rb_thread_struct {
 #ifdef NON_SCALAR_THREAD_ID
     rb_thread_id_string_t thread_id_string;
 #endif
-    BITFIELD(enum rb_thread_status) status : 2;
+    BITFIELD(enum rb_thread_status, status, 2);
     /* bit flags */
     unsigned int to_kill : 1;
     unsigned int abort_on_exception: 1;