import dis
import sys


LOAD_CONST = dis.opmap['LOAD_CONST']


def dump_load_const(code):
    # Do not show first argument
    unused = set(range(1, len(code.co_consts)))
    for _, op, arg in dis._unpack_opargs(code.co_code):
        if op != LOAD_CONST:
            continue
        unused.discard(arg)
    if unused:
        print(f"Code: {code.co_name} {code.co_filename}:{code.co_firstlineno}")
        print("Unused consts:")
        for i in sorted(unused):
            print(f"  {i} {code.co_consts[i]!r}")


def dump_load_const_recursive(code):
    dump_load_const(code)
    for cc in code.co_consts:
        if hasattr(cc, "co_code"):
            dump_load_const_recursive(cc)


def dump_load_const_infile(fn):
    with open(fn, "rb") as f:
        source = f.read()
    code = compile(source, fn, "exec")
    dump_load_const_recursive(code)


if __name__ == '__main__':
    dump_load_const_infile(sys.argv[1])