Wrong resolving of generics inside try/catch block #6353
Description
Code snippet that reproduces the problem
https://phpstan.org/r/ecf86117-177b-439c-b8e3-4e3040a8b6e2
Ends with
Function fromCallbackThatCanThrow() should return Option<T> but returns Option<*NEVER*>.
Additionally, if we set return values to variable as follows:
/**
* @template T
* @param callable():T $fn
* @return Option<T>
*/
function fromCallbackThatCanThrow(callable $fn) {
try {
$a = some($fn());
} catch (Throwable $failure) {
$a = none();
}
return $a;
};https://phpstan.org/r/dca44c7f-7e85-4f99-a66c-0b4629a25901
then the reported error is even more confusing:
Function fromCallbackThatCanThrow() should return Option<T> but returns Option<*NEVER*>|Option<T>.
If never is subtype of T (its universal subtype - bottom type, so it should be) and T is covariant, then Option<never> should be also subtype of Option<T>. So Option<never>| Option<T> should be Option<T>
Expected output
No errors should be reported