Technically yes, but directives are inserted so GDB reports the line number, source code, and parameters of the Nim file. However GDB shows the name mangling s

Technically yes, but directives are inserted so GDB reports the line number, source code, and parameters of the Nim file. However GDB shows the name mangling suffix in generated code, and types are their native types. There's a script called nim-gdb to add pretty printers for types to the GDB output to show the Nim source types. Perhaps surprisingly though, the C and C++ generated output itself is fairly straightforward, even with name mangling suffixes. The inserted directives tell you the Nim source line so you can navigate it fairly well if you want to, and the suffix means the variable is unique referenced in the code. As far as I know you can use any debugger that supports the target language, though I've not tried anything but GDB myself. It's very rare for me to dig into the generated code but sometimes I'm curious about the data structure analog in the target language. In the case of Nim's object variants, last time I looked when compiling to C they were ultimately reduced to simple checked union types.