MediaWiki has a core setting called $wgBlockDisablesLogin; when enabled, blocked users cannot log in. Instead of an all-or-nothing setting, this would make much more sense as a block flag, similar to AbstractBlock::isCreateAccountBlocked() or AbstractBlock::isUsertalkEditAllowed(). For core database blocks, this could be still based on the same configuration flag, but for other types of blocks, it could differ depending on the type of the block, or even the settings of individual blocks. This would allow handling CentralAuth locks or temp user account expiries as blocks, and generally make the block handling logic more intuitive (instead of remembering to check $wgBlockDisablesLogin, there would be an obviously relevant AbstractBlock method; and it would allow more complex and block-type-specific login logic, e.g. for T208895).