Module Windtrap_coverage_ppxSource

The registration of the coverage rewriter with the ppxlib driver.

The module exports no value, and linking it into a driver is its whole interface. When the module is initialized it registers Instrument.transform_impl_file with the ppxlib driver, under the name windtrap_coverage, as a whole-file instrumentation of implementation files.

The instrumentation is positioned after every rewriter that is not itself an instrumentation, so the function receives the expanded file and its points describe the code that runs. The one runtime dependency of the library is windtrap.runtime.

A driver may link this library and ppx_windtrap.mutate together. Of two such instrumentations ppxlib applies first the one that registered last. The driver that dune builds for a stanza naming both backends registers this library first, so the mutation rewriter runs first and this one receives its guards. Neither population is then the one that a single backend gives, and Instrument states what changes.