Mock demeter chains and fluent interface methods with static return type

[kirkbushell]

As per the title, this isn't a solution to #1447 but instead illustrates the bug with a new test case.

We use the static return type for interfaces, as self can result in child classes not being able to work with said interface.

In short, if you have an interface method signature which has a static return type, mockery fails:

ParseError: syntax error, unexpected token "static", expecting identifier

The test case added shows this aspect failing. I've tried solving this but honestly, I am struggling to follow the mockery code, so any guidance would be appreciated and I'll update this PR to solve the problem appropriately.

Note that this can still be done with a hacky utility method we wrote as a wrapper to help us still use demeter chain expectations on interfaces:

protected function demeter(MockInterface $mock, string $chain): HigherOrderMessage|Expectation|ExpectationInterface
{
    $expectations = explode('->', $chain);
    $final = array_pop($expectations);

    $mock->shouldReceive(Arr::mapWithKeys($expectations, fn($expectation) => [$expectation => $mock]));

    return $mock->shouldReceive($final);
}

And it can also be done using array expectations:

$mock->shouldReceive(['do' => $mock, 'thing' => $mock])->andReturn(...);

So it seems to me that something funky is going on specifically with interfaces deeper down in the mockery code. Ideally, we want to be able to support demeter chain mocks on interface methods with static return types.

[codecov]

Codecov Report

❌ Patch coverage is 92.10526% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 78.30%. Comparing base (98e8fda) to head (50c34ad).
⚠️ Report is 1 commits behind head on 1.6.x.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
library/Mockery.php	92.10%	3 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##              1.6.x    #1474      +/-   ##
============================================
- Coverage     78.41%   78.30%   -0.11%     
+ Complexity     1042     1040       -2     
============================================
  Files            76       76              
  Lines          2622     2623       +1     
============================================
- Hits           2056     2054       -2     
- Misses          566      569       +3     

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[ghostwriter]

Hey @kirkbushell,

Thank you for your contribution.

I appreciate the time you invested in preparing this pull request.

I was able to address the issue with a few additional commits.

---

Syntax:

$mock->shouldReceive('do->thing'); or $mock->shouldReceive('do->thing')->andReturnSelf();