Psalm thinks explode() can return false

[simPod]

I have enabled ignoreInternalFunctionFalseReturn="false"

(I cannot do it in playground) https://psalm.dev/r/96ef362b30

explode() returns false when value is empty string.

I asserted the value is not empty string but psalm still reports it can return false

Cannot iterate over falsable var false|non-empty-list

[psalm-github-bot]

I found these snippets:

https://psalm.dev/r/96ef362b30

<?php

/**
 * @return non-empty-list<string>
 */
function takesAString(string $value) : array {
    assert($value !== '');
    return explode(',', $value);
}

foreach(takesAString('h,i') as $entry) {
    echo $entry;
}

Psalm output (using commit 3c66b75):

No issues!

[weirdan]

explode() returns false when value is empty string.

Actually it returns false when separator is empty.
Reproduced in https://psalm.dev/r/6b3a3e88a6

[psalm-github-bot]

I found these snippets:

https://psalm.dev/r/6b3a3e88a6

<?php
/** @param non-empty-string $sep */
function f(string $sep): void {
    $list = explode($sep, "asd");
    if (false === $list) {} // expected: TypeDoesNotContainType: non-empty-list<string> does not contain false
}

Psalm output (using commit 3c66b75):

No issues!

[simPod]

Ah, u're right. I had delimiter in constant as const D = ',';. My brain somehow ruled it out and rather focused on exploded value.