No. The/A compiler does not read a file into a representation that can be converted back to formatted source. E.g. it doesn't even look at parts that are in an inactive IFDEF.
I think that saying "a compiler" there is pushing credibility.
A C/C++ compiler with integrated preprocessor would emit the original file if not told to make changes.
The parser in a compiler normally stores at least one line verbatim so that it can point to the location of an error message, and it would not be difficult to output each line after it had been processed.
A code listing from a compiler normally has the original source in a form that can be extracted.
OK, so FPC doesn't do it like that... but there is no reason why in the general case a single-pass compiler shouldn't emit corrected variable names as it runs, since the symbol table is built before code is generated.
MarkMLl