[PHPStanStaticTypeMapper] Handle Nullable Type on UnionType on UnionTypeMapper when possible

[samsonasik]

Make NullableType correctly applied when possible.

On TypedPropertyFromAssignsRector use case, it correctly apply type use ?DateTime instead of DateTime|null when types keys are not sorted (ensure sort after check types only 2, and one of them is null).

[samsonasik]

The test error on AddFalseDefaultToBoolPropertyRector is caused by overlapped merged PR:

• [CodeQuality] Skip non typed property no default value never assigned on SimplifyEmptyCheckOnEmptyArrayRector #3171
• [Core] Use FullyQualifiedObjectType and ThisType detection for local property fetch on PropertyFetchAnalyzer #3172

There was 1 failure:

1) Rector\Tests\CodingStyle\Rector\Property\AddFalseDefaultToBoolPropertyRector\AddFalseDefaultToBoolPropertyRectorTest::test with data set #4 ('/Users/samsonasik/www/rector-...hp.inc')
Failed asserting that string matches format description.
--- Expected
+++ Actual
@@ @@
     /**
      * @var bool
      */
-    private $property;
+    private $property = false;
 
     public function __construct(bool $property)

which the property is in Trait_, which actually, the __construct() is overrideable from class that consume it, see https://3v4l.org/hsB8k1#v7.0.28

[samsonasik]

I fixed the test for __construct in trait usage, as the __construct can be overridden by class that consume it, https://3v4l.org/MZFmT#v7.0.28

[samsonasik]

All checks have passed 🎉 @TomasVotruba it is ready for review.

[TomasVotruba]

Looks good, thank you 👍