And the code: https://github.com/golang/go/blob/dev.fuzz/src/internal/fuzz/mutator.go https://github.com/golang/go/blob/dev.fuzz/src/internal/fuzz... Edit: and

And the code: https://github.com/golang/go/blob/dev.fuzz/src/internal/fuzz/mutator.go https://github.com/golang/go/blob/dev.fuzz/src/internal/fuzz... Edit: and here's the mechanism that guides mutations towards increased coverage: https://github.com/golang/go/blob/5542c10fbf19cb199d1659c18963f9ed83570746/src/internal/fuzz/fuzz.go#L244 https://github.com/golang/go/blob/5542c10fbf19cb199d1659c189...