###### JerryScript revision

8ba0d1b6ee5a065a42f3b306771ad8e3c0d819bc

###### Build platform

Ubuntu 18.04.5 LTS (Linux 4.15.0-128-generic x86_64)

###### Build steps

```sh
./tools/build.py --clean --debug --logging=on
```

###### Test case

```js
function* g() {
  class A extends (yield) {}
}
g().next();
```

###### Execution steps & output

```
$ ./build/bin/jerry test.js 
ICE: Assertion 'ECMA_STRING_IS_REF_EQUALS_TO_ONE (string_p)' failed at jerryscript/jerry-core/ecma/base/ecma-literal-storage.c(ecma_free_string_list):77.
Error: ERR_FAILED_INTERNAL_ASSERTION
Aborted (core dumped)
```
Assertion 'ECMA_STRING_IS_REF_EQUALS_TO_ONE (string_p)' in ecma_free_string_list
This is a GitHub Issue
repo:jerryscript
owner:jerryscript-project
Title : Assertion 'ECMA_STRING_IS_REF_EQUALS_TO_ONE (string_p)' in ecma_free_string_list
Issue date:

--- start body ---
###### JerryScript revision

8ba0d1b6ee5a065a42f3b306771ad8e3c0d819bc

###### Build platform

Ubuntu 18.04.5 LTS (Linux 4.15.0-128-generic x86_64)

###### Build steps

```sh
./tools/build.py --clean --debug --logging=on
```

###### Test case

```js
function* g() {
  class A extends (yield) {}
}
g().next();
```

###### Execution steps & output

```
$ ./build/bin/jerry test.js 
ICE: Assertion 'ECMA_STRING_IS_REF_EQUALS_TO_ONE (string_p)' failed at jerryscript/jerry-core/ecma/base/ecma-literal-storage.c(ecma_free_string_list):77.
Error: ERR_FAILED_INTERNAL_ASSERTION
Aborted (core dumped)
```
--- end body ---
