Fixed assertion in RegExp built-in. (#2663)

Fixes #2660

JerryScript-DCO-1.0-Signed-off-by: László Langó llango.u-szeged@partner.samsung.com

jerry-core/parser/regexp/re-parser.c

@@ -913,6 +913,7 @@ re_parse_next_token (re_parser_ctx_t *parser_ctx_p, /**< RegExp parser context *
 
       if (!ecma_is_value_empty (ret_value))
       {
+        ecma_free_value (JERRY_CONTEXT (error_value));
         parser_ctx_p->input_curr_p = input_curr_p;
         ret_value = ECMA_VALUE_EMPTY;
       }

tests/jerry/regression-test-issue-2660.js

@@ -0,0 +1,20 @@
+// Copyright JS Foundation and other contributors, http://js.foundation
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+try {
+  new RegExp("\{{91[06,456}");
+  assert (false);
+} catch (e) {
+  assert(e instanceof SyntaxError);
+}