modernize-redundant-void-arg doesn't detect problems inc included files (trunk version as of r255909). Problem could be reproduced by moving part of test into other file and include it in test.
You can assign this to me, I'll probably have a fix ready for review over the Christmas break.
OK, looks like I can assign it to myself, so never mind :)
It looks like you just need to remove isExpansionInMainFile from all matchers in this check (and the readability-simplify-boolean-expr check as well). Clang-tidy takes care of filtering the results by file itself.
(In reply to comment #3) > It looks like you just need to remove isExpansionInMainFile from all > matchers in this check (and the readability-simplify-boolean-expr check as > well). Clang-tidy takes care of filtering the results by file itself. I tried to remove isExpansionInMainFile() from RedundantVoidArgCheck.cpp and check worked for me in case of included files.
Fixed in r260948.