Missing tokens when source code too long?

[kenny1269]

I parse .m files written in Objective-C using ClangKit, when the source code is about over 300 lines, I find out that the source code is truncated and no tokens about the missing part, the snapshot bellow shows the problem.

If the source code is not too long, it works fine.
I have check out the source code, but can't find any problem.
I am very confused about this, can any one help? Thanks a lot.

[kenny1269]

Running on xcode 9.4.1 and xcode 10.1 get the same problem.