19. Perf contracts

This edition does not carry this chapter.

Perf contracts are the four promises a function can make about its own execution — no allocation, in-place work, no trap on the failure path, a bounded stack — and the whole method of the chapter is to break one and read the compiler’s objection. The objection is what a reader would learn from, and the toolchain this edition names does not raise it: the attributes parse and nothing verifies them. A chapter that showed the promises without the enforcement would teach a comment with better syntax, so the section numbers below are reserved and the pages are not written.

What Part 4 does carry is chapter 18 on comptime, and chapters 22 through 24 on modules, packages, and the covenant. Chapter 8’s region claims and chapter 12’s channel costs both point here for their measurements; until this chapter and the two after it exist, those claims stand on the numbers their own chapters print.