Variadic callables type checking failed

[klimick]

https://psalm.dev/r/579db4822c

Actually I already have a fix for this problem.
But I don't know which branch to open PR.
master? v5?

[psalm-github-bot]

I found these snippets:

https://psalm.dev/r/579db4822c

<?php

function withVariadicParam(int $a, int $b, int ...$rest): int
{
    throw new RuntimeException();
}

/** @param Closure(int, int): int $f */
function int_int(Closure $f): void {}

/** @param Closure(int, int, int): int $f */
function int_int_int(Closure $f): void {}

/** @param Closure(int, int, int, int): int $f */
function int_int_int_int(Closure $f): void {}

/** @param Closure(int, int, int, string): int $f */
function int_int_int_string(Closure $f): void {}

// false positive: expected no issues here
int_int(withVariadicParam(...));

// ok: but that's because the number of parameters are the same.
int_int_int(withVariadicParam(...));

// ok: but last param actually does not type checked.
int_int_int_int(withVariadicParam(...));

// false negative: expected issue here
int_int_int_string(withVariadicParam(...));

Psalm output (using commit 73ebe22):

ERROR: InvalidScalarArgument - 21:9 - Argument 1 of int_int expects Closure(int, int):int, but impure-Closure(int, int, int...):int provided

[orklah]

You can target V5 as long as there's no BC break :)