b4ccc970

By: Tom Sydney Kerckhove <syd@cs-syd.eu>

Mutation: per-mutation mitigation hints + binding name in manifest & report

Replace the operator alternative 5-tuple with a MutationAlt record carrying
an extra optional mitigation message (mutAltMitigation), so an operator can
explain how a mutation it produced may be mitigated.  All operators are
converted; only SwitchFunctionArguments sets a message (pointing at
skip-calls-to for the symmetric-function case).

Add two optional fields to the manifest record (and the augmented manifest):
  * mitigation  -- the operator's hint, carried through to the report.
  * binding     -- the enclosing top-level binding name, threaded through
                   InstrumentEnv during instrumentation.

The mutation run report now prints, under each surviving mutation, the exact
disable annotation for it ({-# ANN <binding> ("DisableMutation: <Op>" ...) #-})
and any mitigation hint, via the new survivorMitigationLines.

Bumps sydtest to 0.26.1.0 (new export, report output) and documents the
plugin changes.  Goldens regenerated; example gen specs unchanged (all swap
mutants still killed).

Timeline