I removed failing fixtures for Closure/ArrowFunction add return 6515c39, based on them, I think we can categorize by type, eg:

• AddClosureArrayReturnTypeRector
• AddClosureScalarReturnTypeRector
• AddClosureUnionReturnTypeRector
• etc

that can be in separate PRs to add first, before it can be merged so all features covered first...

existing rules for Closure are:

• AddClosureVoidReturnTypeWhereNoReturnRector

for ArrowFunction, we have already AddArrowFunctionReturnTypeRector ;)

Could you rebase this one? I want to merge it before I do some duplicated/conflicting changes in the set

I think I can close it for now, to revisit later for possible more by type improvement, as currently the left over is too detail and make it too much rules to extract...

I see, I'll look into it