@kenjis the AddParamTypeDeclarationRector should already fixed at rectorphp/rector-src#1239

I will try looking at why there is another error Rector\StaticTypeMapper\PhpDocParser\IdentifierTypeMapper::mapStatic() must implement interface PHPStan\Analyser\Scope, null given

Fixing for error is "Rector\StaticTypeMapper\PhpDocParser\IdentifierTypeMapper::mapStatic() must implement interface PHPStan\Analyser\Scope, null given" coming at rectorphp/rector-src#1243

@kenjis could you rebase latest develop, run composer update, and re-run rector to verify if the error is solved?

Oh, it still error in other place:

vendor/bin/rector process --dry-run --no-progress-bar

Error: ] Could not process "system/I18n/Time.php" file, due to:                 
         "Argument 1 passed to                                                  
         Rector\StaticTypeMapper\PhpDocParser\IdentifierTypeMapper::mapStatic() 
         must implement interface PHPStan\Analyser\Scope, null given, called in 
         vendor/rector/rector/packages/StaticTypeMapper/PhpDocParser/IdentifierT
         ypeMapper.php:92". On line: 132  

I will check on rector side.

fix on error above is coming to rector rectorphp/rector-src#1248

@kenjis please rebase again as rector updated to 0.12.5, it should be working ok now ;)