BFM-decomp/cookbook/C0120.md

§109 — Conforming a definition to a shared header: fix the NAMES, then check the RETURN precondition (Phase 29 T60)

reconcile_def_sig substituted the canonical header decl wholesale — types AND parameter names — while the body kept the exemplar's names. Its docstring called this a "rare name mismatch" the gate would reject; both halves were wrong. An exemplar drafted with the param_N convention hits it every time, and the outcome is not a rejected match but the whole family booking as a compile failure, indistinguishable from a compiler wall:

canonical : void func_8014D610(s32 a0, void *a1, void *a2)
draft body: ... param_1 ...            ->  `param_1' undeclared (first use this function)

Fix: conform the TYPES, keep the BODY's names — both are in hand at the call site. Parse with cdecl (base = return type, params = types, pnames = names), not a regex. Two traps in the re-render: void* + a1 must become void *a1 (cdecl glues the stars to the type), and an empty parameter list must be handed back verbatim — (void) and () both parse to params == [], and they are different declarations (§99: () is the no-prototype form).

The fix is real but it is not sufficient, and the proof is that the verdicts MOVED:

family	before	after	what is left
func_8016163C	param_1 undeclared	DIFF	plumbing fully cleared; genuine codegen
func_8014D610	param_1 undeclared	void value not ignored as it ought to be	the header is wrong
func_80156044	unchanged	conflicting types for func_80155FF8	wrong lever — a CALLEE conflict

The §85 return-axis precondition applies here too, and nothing checks it. Conforming a definition's return type to the canonical void is only safe when no caller consumes the return. func_8014D610's callers do — so the header's void contradicts the byte truth, and conforming to it produces void value not ignored. The header is the thing that is wrong; changing it is fleet-shared blast radius. reconcile_def_sig should test that precondition before promoting or demoting a return type, exactly as §85 requires of conform_decls.

And a verdict that changes is the signal to re-route, not to push harder. One of these three is now a codegen question, one is a header-correctness question, and one was never the def signature at all. They shared a symptom, not a cause — three families, three levers.

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