[Feature] Add 3 new rectors for fixing incorrect null type in @var, @param and @return

[dorrogeray]

Hi, here are 3 rectors which I wanted to share. I have added them to the TypeDeclaration directory but if there is a better place please let me know.

• ParamAnnotationIncorrectNullableRector
  • Adds or removes null type from @param phpdoc typehint based on php parameter type declaration
• ReturnAnnotationIncorrectNullableRector
  • Adds or removes null type from @return phpdoc typehint based on php return type declaration
• VarAnnotationIncorrectNullableRector
  • Adds or removes null type from @var phpdoc typehint based on php property type declaration

Some background info: Basically we had a lot of these problems in our project where the phpdocs were incorrect, ie the php type was nullable, for example ?array but the php doc said it was simply SomeObject[], not SomeObject[]|null as it should. Or vice versa, the phpdoc stated it was SomeObject[]|null but it was actually non nullable array type. Among other things, this was then confusing phpstan and leading to all sorts of problems. These 3 rector rules solved this problem for us.

[samsonasik]

@dorrogeray btw, could you extract into 3 PRs for the 3 rules?

[dorrogeray]

@samsonasik Thanks, I have removed the UnionTypeAnalyzer and used the TypeCombinator instead. I have also sent separate PR for the first rule VarAnnotationIncorrectNullableRector

I will send the next separate PR once this one is merged, so that I can rebase and prevent conflicts (rules share some code and docs need to be regenerated).

[dorrogeray]

All three rules have been merged, so I am closing this PR. Thanks! 👍

[TomasVotruba]

Thank you for your work @dorrogeray 👏