Describe the bug
File to_cpp1.h.
Line 6722.
Expression assert(n.initializer);.

To Reproduce
Steps to reproduce the behavior:

1. Download source code of cppfront.
2. Compile cppfront.
3. Run cppfront on test.cpp2 file.
4. Assert triggers inside cppfront.

Additional context
Test.cpp2 file's content is only 3 bytes long and it is: r:;.