For others encountering a similar situation, when commenting out portions of code does not help or running a nim compiler with debugging symbols does not help either, here is what I've done.
1. Searching in [Nim issues](https://github.com/nim-lang/Nim/issues?utf8=%E2%9C%93&q=is%3Aissue+is%3Aopen+fatal.nim%2839%29+sysFatal) shows that the compiler has become more sensitive to syntax errors lastly. 2. From that, I decided to run it with different versions of the compiler, and using the [Playground](https://playground.nim-lang.org/) does not require you to install many old versions on your computer. I found that version 0.19.6 reported exactly the symbol where the compiler was choking. Correcting it, I was able to switch back to version 1.0.4 and continue correcting the remaining syntax errors.
