Bug report

The type \Closure(string)|\Closure(string, string) is collapsed to \Closure(string, string), with the assumption that \Closure(string) is covered by \Closure(string, string). This seems wrong, when considering optional parameters.

It's true that

$closure("Hello", "World");

can be passed to \Closure(string) as extranous parameters are ignored by php. But considering \Closure(string, int=) the above doesn't hold and produce an error.

Code snippet that reproduces the problem

https://phpstan.org/r/f502c295-dde6-4647-9dd7-1f4bd1ba6219

Expected output

I would expect \Closure(string)|\Closure(string, string) to not be collapsed to \Closure(string, string)

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