The same treatment the `PNode` side just got, for the reason that applies to
types: `t[0]` is the return type, the base class, the index type or the generic
head depending on the kind, and the subscript says none of that. Every child
access in the cgen files that has a named accessor now uses it — `baseClass`
for the eleven object-hierarchy walks, `elementType` for the seq/openArray
element, `returnType`, `genericHead`, `firstGenericParam` — and the two loops
that walked a type's children become `paramTypes` and `kids`.
Left indexed on purpose: a parameter reached by ARGUMENT position
(`typ[i]` in ccgcalls/ccgstmts), a tuple field, and a generic parameter at an
explicit index. There the index is the clearest thing to write.
Every substitution is exact rather than merely close. `[]` with index 0 is
unconditionally `sonsImpl[0]`, so `baseClass`/`returnType`/`genericHead` cannot
diverge; `elementType` is `sonsImpl[^1]` and is used only where the type has a
single son; `paramTypes` and `kids` are literally the loops they replace.
`ast.sons(t: PType)` gets the warning it has been missing. Despite the name it
is not the counterpart of the `sons` ITERATOR over a `PNode`: it returns the
raw seq, and a `tyProc` keeps its parameter types in `n`, so that seq holds
only the return type while `[]`/`len`/`kids` route parameters through
`n[i].sym.typ`. `for x in t.sons` therefore compiles, reads exactly like the
`PNode` idiom, and visits a different set of types — which is what
`ccgutils.encodeType` would have started doing had it been converted to `sons`
rather than `kids`. Marking the proc deprecated and rebuilding shows one call
site in the whole compiler (`previouslyInferred`), so the trap is latent, not
active.
`bnode.nim` also records that there is deliberately no `BType` beside `BNode`:
types stay `PType`s under `newIcBackend` — `BNode.typ` returns one — because
the backend asks them questions (`skipTypes`, `getSize`, `lengthOrd`, the
record walk over `t.n`) that a raw cursor cannot answer.
Pure refactor: all 216 generated `.c` files byte-identical to the parent commit.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FMyRHByv7hhaQJ4Pa1bHbE
2447dfdc7d