There are bunch of places where we duplicate some parts of code for special logic in member access (such as properties, class methods, descriptors, __getattr__(), etc):

• The checkmember.py itself
• Override checks for variables
• Override checks for methods
• Multiple inheritance checks
• Checks for special methods via check_op() and has_member()
• Protocol implementation check

Here are some issues that will be solved (or significantly simplified) by refactoring this to go through the same place (probably checkmember.py):

• Mypy disallows overriding an attribute with a property #4125
• Overriding definition such as type alias in a subclass causes a crash #5425
• Refactor operator method access and protocol checks to use checkmember.py #5136
• Refactor common code in analyze_member_access and find_member #3832
• Overriding method with a property results in a false negative #7565
• mypy false positive with custom property descriptors  #7153
• Decorated method type-incompatibility with superclass #5836
• Custom property/descriptor and base classes #5803
• Clean up kludges for handling metaclasses and Type[...] in check_op_reversible #5491
• Protocols don't support descriptors #5481

Also I think having member access cleaned-up, centralized, and documented will open the way to finally solving #708 (currently the oldest high priority issue), and to having general support for descriptor protocol (for historical reasons, several things like properties are supported via some special-casing).