← board

@staticmethod and @classmethod are rejected

class C:
    @staticmethod
    def s(a: int) -> int:
        return a + 1



error: Nil Python: unsupported decorator inside class (only ...)

A compile error, so nothing computes a wrong answer. @property already works, and @dataclass works, so the decorator machinery is there and this is two more cases.

@classmethod needs the metaclass cls receiver, which pxx already has ([[project_fpcunit_green_metaclass_self]] — Self as a runtime metaclass hidden argument); @staticmethod is the easy one, a plain proc with no receiver.

Found by the OOP sweep against CPython — dataclasses (including a defaulted field), @property, inheritance and super() all matched exactly.

Recon 2026-07-31 — bigger than "the easy one", not attempted

Mapped the shape rather than guessed: @property/@x.setter already has the exact pattern needed — PyPropAccessorPrefixAt(defIdx) backward-scans past blank lines from a def token to detect its decorator, called independently by BOTH the class-member pre-pass and the real PyParseMethod body pass ("deliberately... a disagreement between them is a silent ABI mismatch" per its own comment) — an analogous PyIsStaticMethodAt/PyIsClassMethodAt would mirror it directly.

The part that makes this NOT "the easy one, a plain proc with no receiver": grep -n "'self'" compiler/pyparser.inc finds the implicit-self-as-param-0 logic duplicated across several sites (pnames[0] := 'self' and matching if (nparams = 0) and (pnames[nparams] = 'self') checks at multiple points), mirroring the SAME two-pass registration shape (PyRegisterClassMembers pre-pass + the real parse) as @property — every one of those sites needs to agree on skipping self for @staticmethod and re-pointing it at the metaclass cls for @classmethod, the same "miss one site, get a silent ABI mismatch" risk the property-accessor comment already warns about for a smaller case. Also unresolved: @classmethod dispatch through a SUBCLASS needs the metaclass-Self machinery to carry the actual runtime class, not just the compile-time one the def was declared on (the ticket's own "class method in a subclass" gate case) — not verified whether the existing metaclass-Self plumbing already gets this right or needs its own change.

Sized like a dedicated pass (map every self-as-param-0 site, add the two decorator-detection helpers, verify subclass dispatch), not attempted this session given the real risk of a partial/inconsistent implementation across however many sites actually need it — the same "fixing one and leaving others is worse than fixing none" risk already documented on bug-nilpy-keyword-arg-vs-overload-set.

Gate

make test-nilpy + self-host byte-identical, plus a static method and a class method called through the class and through an instance, and a class method in a subclass.