I'm often only interested in matches within the main-file or matches that are not within a system-header, so for this purpose i added the two matchers isInMainFile and isInSystemFile. They take no arguments and narrow down the matches. The isInFileMatchingName is mainly thought for interactive clang-query-sessions, to make a matcher more specific without restarting the session with the files you are interested in for that moment. It takes a string that will be used as regular-expression to match the filename of where the matched node is expanded.
I was just curious that there is no typedefDecl-matcher, so I'm adding this one to this commit, too.
I'm not sure if the tests are sufficient but I have no good clue what tests would add more value.