SQUASH ME: Keep in _encodingCantBeStoredInEightBitCFString's use of _core

Author: milseman

Foundation/NSString.swift

@@ -304,6 +304,9 @@ open class NSString : NSObject, NSCopying, NSMutableCopying, NSSecureCoding, NSC
     }
 
     internal var _encodingCantBeStoredInEightBitCFString: Bool {
+        if type(of: self) == NSString.self || type(of: self) == NSMutableString.self {
+            return !_storage._core.isASCII
+        }
         return false
     }