Bug report

Given a variable of type string|false, is_numeric fails to refine out false from the possible types, despite is_numeric(false) === false.

Code snippet that reproduces the problem

How I discovered this (roughly):
https://phpstan.org/r/85224f3b-91f7-4aa8-afa1-316466fb5bf5

Most generically:
https://phpstan.org/r/be0f3875-2615-46fb-bed9-28e400dc2d98

php > var_dump(is_numeric(false));
php shell code:1:
bool(false)

Expected output

No error