wasm-ld crash on dynamic linking + debugging symbols

[gl84]

While trying to debug an error I encountered the following wasm-ld crash (stacktrace from 4.0.21-asserts):

wasm-ld: /b/s/w/ir/cache/builder/emscripten-releases/llvm-project/llvm/include/llvm/Support/Casting.h:572: decltype(auto) llvm::cast(From *) [To = lld::wasm::DefinedFunction, From = const lld::wasm::Symbol]: Assertion `isa<To>(Val) && "cast<Ty>() argument of incompatible type!"' failed.
wasm-ld: /b/s/w/ir/cache/builder/emscripten-releases/llvm-project/llvm/include/llvm/Support/Casting.h:572: decltype(auto) llvm::cast(From *) [To = lld::wasm::DefinedFunction, From = const lld::wasm::Symbol]: Assertion `isa<To>(Val) && "cast<Ty>() argument of incompatible type!"' failed.
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace and instructions to reproduce the bug.

It can be reproduced easily:

echo >main.cpp 'int main() {   return 0; }' && echo >side.cpp '#include <string>
#include <emscripten.h>
EMSCRIPTEN_KEEPALIVE void test_string_assignment(char* argv[]){
    std::string s;
    s = argv[0];
}
' && em++  -o side.so -sFAKE_DYLIBS=0  -shared  -sSIDE_MODULE=1 side.cpp && em++ -g  -O0 -sMAIN_MODULE=1  main.cpp  -o main.js       side.so

Compiling the main module without debugging symbols works as expected.

The crash happens in 4.0.21, 4.0.22 and tot.