Fix #187

Author: yhirose

peglib.h

@@ -3904,13 +3904,17 @@ struct AstOptimizer {
                               std::shared_ptr<T> parent = nullptr) {
     auto found =
         std::find(rules_.begin(), rules_.end(), original->name) != rules_.end();
-    bool opt = mode_ ? !found : found;
+    auto opt = mode_ ? !found : found;
 
     if (opt && original->nodes.size() == 1) {
       auto child = optimize(original->nodes[0], parent);
-      return std::make_shared<T>(*child, original->name.data(),
-                                 original->choice_count, original->position,
-                                 original->length, original->choice);
+      auto ast = std::make_shared<T>(*child, original->name.data(),
+                                     original->choice_count, original->position,
+                                     original->length, original->choice);
+      for (auto node : ast->nodes) {
+        node->parent = ast;
+      }
+      return ast;
     }
 
     auto ast = std::make_shared<T>(*original);

test/test1.cc

@@ -967,3 +967,18 @@ TEST(GeneralTest, token_to_number_float_test) {
   EXPECT_TRUE(ast->nodes.empty());
 }
 
+TEST(GeneralTest, ParentReferencesShouldNotBeExpired) {
+	auto parser = peg::parser(R"(
+		ROOT            <- OPTIMIZES_AWAY
+		OPTIMIZES_AWAY  <- ITEM+
+		ITEM            <- 'a'
+	)");
+	parser.enable_ast<peg::Ast>();
+
+	std::shared_ptr<peg::Ast> ast;
+	parser.parse("aaa", ast);
+	ast = parser.optimize_ast(ast);
+
+	EXPECT_FALSE(ast->nodes[0]->parent.expired());
+}
+