This is a regression between 1.5.8 and 1.5.9.  If I have an ObjC class like this:

@interface MyStructClass : NSObject {
    struct {
        unsigned int _used;
        unsigned int _reserved;
    } _s;
    int _i;
}
- (int)aMethod;
@end


doxygen 1.5.8 will properly identify the aMethod method as a virtual function:

    <member kind="function" virtualness="virtual">
      <type>int</type>
      <name>aMethod</name>
      <anchorfile>interface_my_struct_class.html</anchorfile>
      <anchor>89673546ff21f82f35ccd79aac28fcfa</anchor>
      <arglist>()</arglist>
    </member>

In doxygen 1.5.9, it (and any other methods in the class) get identified as a protected variable:

    <member kind="variable" protection="protected">
      <type>int</type>
      <name>aMethod</name>
      <anchorfile>interface_my_struct_class.html</anchorfile>
      <anchor>65c91d18e131ae97a78bc6e5165588c6</anchor>
      <arglist></arglist>
    </member>

Removing the struct, gives correct results in both versions of doxygen.