Is it possible to introspect the array's type in Objective-C Generics -- Xcode 7+

Question

I use this to get the class for a property name:

- (Class)gm_classForPropertyName:(NSString *)propertyName {
    objc_property_t prop = class_getProperty([self class], propertyName.UTF8String);
    const char * attr = property_getAttributes(prop);
    NSString *attributes = [NSString stringWithUTF8String:attr];
    NSArray *components = [attributes componentsSeparatedByString:@"\""];
    Class propertyClass;
    for (NSString *component in components) {
        Class class = NSClassFromString(component);
        if (class) {
            propertyClass = class;
            break;
        } else {
            class = swiftClassMapping[component];
            if (class) {
                propertyClass = class;
                break;
            }
        }
    }
    return propertyClass;
}

But this is the important part:

    objc_property_t prop = class_getProperty([self class], propertyName.UTF8String);
    const char * attr = property_getAttributes(prop);
    NSString *attributes = [NSString stringWithUTF8String:attr];

When I log attributes, it still looks like an untyped NSArray as a string. Is there some way to introspect the class type?

T@"NSArray",&,N,V_children

tl;dr

Take this class:

@interface SomeClass : NSObject <GenomeObject>
@property (strong, nonatomic) NSArray<SomeOtherClass *> *children;
@end

Given the class SomeClass, and the property name children is there a way for me to find that children is an array of SomeOtherClass type objects?

Answer 1

According to the WWDC talks about this feature, it is implemented using type erasure. That means that information about the generic is removed during compilation and not present at runtime.

This is the relevant video: https://developer.apple.com/videos/wwdc/2015/?id=401. The lightweight generics discussion starts at about 22 minutes. At 27:20 they explain that it is implemented using type erasure.