diff --git a/include/mruby/compile.h b/include/mruby/compile.h
index 652cb730c..29d1a324f 100644
--- a/include/mruby/compile.h
+++ b/include/mruby/compile.h
@@ -123,7 +123,7 @@ struct mrb_parser_heredoc_info {
 /* parser structure */
 struct mrb_parser_state {
   mrb_state *mrb;
-  struct mrb_mempool *pool;
+  mrb_mempool *pool;
   mrb_ast_node *cells;
   const char *s, *send;
 #ifndef MRB_NO_STDIO
diff --git a/include/mruby/mempool.h b/include/mruby/mempool.h
index c2cd58119..6a4cd7811 100644
--- a/include/mruby/mempool.h
+++ b/include/mruby/mempool.h
@@ -12,7 +12,7 @@ MRB_API void* mempool_alloc(struct mempool*, size_t);
 MRB_API void* mempool_realloc(struct mempool*, void*, size_t oldlen, size_t newlen);
 
 /* compatibility layer */
-#define mrb_mempool mempool
+typedef struct mempool mrb_mempool;
 #define mrb_mempool_open(m) mempool_open()
 #define mrb_mempool_close(m) mempool_close(m)
 #define mrb_mempool_alloc(m, size) mempool_alloc((m),(size))