Bug report

The signature of getenv indicates that it will accept null as the first argument:

$ php83 --rf getenv
Function [ <internal:standard> function getenv ] {

  - Parameters [2] {
    Parameter #0 [ <optional> ?string $name = null ]
    Parameter #1 [ <optional> bool $local_only = false ]
  }
  - Return [ array|string|false ]

but PHPStan reports that it doesn't.

The linked playground doesn't split on PHP versions, which is something I might have expected:

$ php74 --rf getenv
Function [ <internal:standard> function getenv ] {

  - Parameters [2] {
    Parameter #0 [ <optional> $varname ]
    Parameter #1 [ <optional> $local_only ]
  }
}

but even then calling getenv(null) just returns false instead of raising any errors.

Code snippet that reproduces the problem

https://phpstan.org/r/311dcf74-0d42-411c-a4ce-c7c4061b6291

Expected output

No error (maybe error in PHP7?).

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