diff --git a/node.c b/node.c
index 370e6df5ce..abaaf19c7d 100644
--- a/node.c
+++ b/node.c
@@ -1136,14 +1136,3 @@ rb_ast_add_mark_object(rb_ast_t *ast, VALUE obj)
 {
     rb_ary_push(ast->mark_ary, obj);
 }
-
-void
-rb_ast_delete_mark_object(rb_ast_t *ast, VALUE obj)
-{
-    long i;
-    for (i = 0; i < RARRAY_LEN(ast->mark_ary); i++) {
-	if (obj == RARRAY_AREF(ast->mark_ary, i)) {
-	    RARRAY_ASET(ast->mark_ary, i, Qnil);
-	}
-    }
-}
diff --git a/node.h b/node.h
index 488a8ce2ef..b18d96357a 100644
--- a/node.h
+++ b/node.h
@@ -479,7 +479,6 @@ void rb_ast_mark(rb_ast_t*);
 void rb_ast_dispose(rb_ast_t*);
 void rb_ast_free(rb_ast_t*);
 void rb_ast_add_mark_object(rb_ast_t*, VALUE);
-void rb_ast_delete_mark_object(rb_ast_t*, VALUE);
 NODE *rb_ast_newnode(rb_ast_t*);
 void rb_ast_delete_node(rb_ast_t*, NODE *n);
 
diff --git a/parse.y b/parse.y
index e73c266cc2..95c7f9bf12 100644
--- a/parse.y
+++ b/parse.y
@@ -6123,14 +6123,6 @@ parser_regx_options(struct parser_params *parser)
     return options | RE_OPTION_ENCODING(kcode);
 }
 
-static void
-dispose_string(struct parser_params *parser, VALUE str)
-{
-    rb_ast_delete_mark_object(parser->ast, str);
-    rb_str_free(str);
-    rb_gc_force_recycle(str);
-}
-
 static int
 parser_tokadd_mbchar(struct parser_params *parser, int c)
 {
@@ -6907,7 +6899,6 @@ parser_here_document(struct parser_params *parser, rb_strterm_heredoc_t *here)
 	    }
 	    if (nextc() == -1) {
 		if (str) {
-		    dispose_string(parser, str);
 		    str = 0;
 		}
 		goto error;