[lld-link] error : duplicate symbol

[co-neco]

Hi, I want to build mariadb using CLANGCL toolset on windows.

How to reproduce the issue:
There are two source files as below:
hello.cpp

#include <iostream>

extern void ttt();

int main() {
    std::cout << "Hello, World!" << std::endl;
    ttt();
    return 0;
}

ttt.cpp

#include <iostream>

void ttt() {
    std::cout << "hello world\n";
}

The main.cpp use an extern function ttt defined in ttt.cpp, I have following build steps:

1. use cl compiler to build ttt.obj, hello.obj
2. use lib to build ttt.lib
3. use link to link ttt.lib and hello.obj to hello.exe:
   link /OUT:"hello.exe" ttt.lib /machine:ARM64 hello.obj ttt.obj
   the above process was successful.
   But if I use lld-link to run the linker command:
   lld-link /OUT:"hello.exe" ttt.lib /machine:ARM64 hello.obj ttt.obj
   It complained that

lld-link: error: duplicate symbol: void __cdecl ttt(void)
>>> defined at ttt.obj
>>> defined at ttt.lib(ttt.obj)

And if I run:
lld-link /OUT:"hello.exe" ttt.lib /machine:ARM64 hello.obj
It completed without error.

I think the implementations in ttt.lib and ttt.obj can both exist in the linker command, because ttt is the same one, so lld-link can choose only one, like what Windows link.exe does, is it right?