It would be great to have tooling like "cargo fuzz coverage ", that creates a binary with coverage instrumentation, then runs it on the corpus and generates an LLVM .profdata file.

This can then be used to generate an HTML report using:

cargo cov -- show fuzz/target/<target triple>/release/my_compiler \
    --format=html \
    -instr-profile=fuzz/coverage/my_compiler/coverage.profdata \
    > index.html

From my perspective this is maybe one of the last key things that are missing from test-fuzz that are available in cargo-fuzz.