The ClassKind enum is used in AggregateDeclaration AST nodes to specify the linkage type of the struct/class/interface or if it is an anonymous class. If the class is anonymous it is also considered to be a D class.
the aggregate is a d(efault) class
the aggregate is a C++ struct/class/interface
the aggregate is an Objective-C class/interface
The D Programming Language's Unofficial Docs
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The ClassKind enum is used in AggregateDeclaration AST nodes to specify the linkage type of the struct/class/interface or if it is an anonymous class. If the class is anonymous it is also considered to be a D class.