IntelliSense crashes in C file

**Type: LanguageService**

- OS: Archlinux
- GCC: 8.2.1

## Step to reproduce
1. Create a 'C' file._(This crash only happens in the 'C' file)_
```c
int main(void) {
}
```

2. Declare a function before main.
```c
static void test(int);// IntelliSense crashes when I type 'int'

int main(void) {
}
```

3. C/C++ Output.
`Failed to read response from server: 8`
