Member editors accept renames that create duplicate member names

The member editors accept a rename that gives two members the same name, and the conflict is only reported afterwards by the compiler in the error list.

In a class, window, or container control, adding a second enumeration is correctly numbered (for example MyEnum1), but renaming that enumeration back to MyEnum is accepted, producing two enumerations named MyEnum. The name field shows no warning; the problem appears only as the compile error "Type 'MyContainer.MyEnum' is already declared."

The same gap applies to other member kinds:

• Renaming a property or constant to an existing method's name is accepted and fails compilation with "defines both a property and a method named '…'".
• Renaming a method to an existing property or constant name is accepted and fails compilation the same way.

Renaming a member to a conflicting name should be rejected immediately with a clear message, the way duplicate property and constant names already are.