objective c - Why does IDA show a method that a class-dump can't? And why can't I hook it? -

when doing class-dump on instagram (v7.7), confused on why in class, method declaration "sponsoredcontext" missing. in comparison, ida shows "-(char)sponsoredcontext" method.

class dump result:

@interface igfeeditemtimelinelayoutattributes : xxunknownsuperclass {     bool _sponsoredcontext;     bool _showexplorecontext;     bool _showtimestamponfirstlayoutelement;     igfeeditem* _feeditem;     nsarray* _rowitems; } @property(retain, nonatomic) nsarray* rowitems; @property(assign, nonatomic) bool showtimestamponfirstlayoutelement; @property(assign, nonatomic) bool showexplorecontext; @property(assign, nonatomic) bool sponsoredcontext; @property(retain, nonatomic) igfeeditem* feeditem; -(void).cxx_destruct; -(id)commentfortexttimelinerow:(int)texttimelinerow; -(int)celltypefortexttimelinerow:(int)texttimelinerow; -(int)numberoftextrowsintimeline; -(id)initwithfeeditem:(id)feeditem sponsoredcontext:(bool)context showexplorecontext:(bool)context3 showtimestamponfirstlayoutelement:(bool)element; @end 

ida result:

igfeeditemtimelinelayoutattributes - (char)sponsoredcontext char __cdecl -[igfeeditemtimelinelayoutattributes sponsoredcontext](struct igfeeditemtimelinelayoutattributes *self, sel) __igfeeditemtimelinelayoutattributes_sponsoredcontext_  mov             r1, #(_objc_ivar_$_igfeeditemtimelinelayoutattributes._sponsoredcontext - 0x15c64) add             r1, pc ldr             r1, [r1] ldrsb           r0, [r0,r1] bx              lr end of function -[igfeeditemtimelinelayoutattributes sponsoredcontext] 

also, when try hook method using logos:

%hook igfeeditemtimelinelayoutattributes -(bool)sponsoredcontext{     nslog(@"text:%d", %orig());     return %orig(); } %end 

cydia substrate gives me error:

ms:warning: message not found [igfeeditemtimelinelayoutattributes sponsoredcontext:] 

how can hook method? why doesn't class-dump show it, ida does? what's special method?

thanks in advance.