Code
---
void f()
{
  const char* c="aaaaa";
  g(c);
}

extern void g(in char* s);
---

Gives disassembler output
---
void example.f():
	push   rbp
	mov    rbp,rsp
	mov    edi,0x0
	call   e <void example.f()+0xe>
	pop    rbp
	ret    
---

The function is called with null argument?