Method execute_call_vectorcall

crates/vm/src/frame.rs:6554–6604

(&mut self, nargs: u32, vm: &VirtualMachine)

    /// Uses vectorcall slot if available, otherwise falls back to FuncArgs.
    #[inline]
    fn execute_call_vectorcall(&mut self, nargs: u32, vm: &VirtualMachine) -> FrameResult {
        let nargs_usize = nargs as usize;
        let stack_len = self.localsplus.stack_len();
        debug_assert!(
            stack_len >= nargs_usize + 2,
            "CALL stack underflow: need callable + self_or_null + {nargs_usize} args, have {stack_len}"
        );
        let callable_idx = stack_len - nargs_usize - 2;
        let self_or_null_idx = stack_len - nargs_usize - 1;
        let args_start = stack_len - nargs_usize;

        // Build args: [self?, arg1, ..., argN]
        let self_or_null = self
            .localsplus
            .stack_index_mut(self_or_null_idx)
            .take()
            .map(|sr| sr.to_pyobj());
        let has_self = self_or_null.is_some();

        let effective_nargs = if has_self {
            nargs_usize + 1
        } else {
            nargs_usize
        };
        let mut args_vec = Vec::with_capacity(effective_nargs);
        if let Some(self_val) = self_or_null {
            args_vec.push(self_val);
        }
        for stack_idx in args_start..stack_len {
            let val = self
                .localsplus
                .stack_index_mut(stack_idx)
                .take()
                .unwrap()
                .to_pyobj();
            args_vec.push(val);
        }

        let callable_obj = self
            .localsplus
            .stack_index_mut(callable_idx)
            .take()
            .unwrap()
            .to_pyobj();
        self.localsplus.stack_truncate(callable_idx);

        // invoke_vectorcall falls back to FuncArgs if no vectorcall slot
        let result = callable_obj.vectorcall(args_vec, effective_nargs, None, vm)?;
        self.push_value(result);
        Ok(None)
    }

    /// Vectorcall dispatch for Instruction::CallKw (positional + keyword args).
    #[inline]