The `BNode` accessors had no oracle. The self-test in `bnode.nim` checks them
against each other and against the raw token stream, which a uniformly wrong
vocabulary satisfies — it passed 5.2M assertions on an off-by-two model. This
adds the missing oracle and lets it drive the next migration step.
`cgen.grindLockstep` (opt-in, `NIM_IC_BNODE_GRIND=1` on an `--ic:on` build)
walks the `.bif` cursor and the materialised `PNode` for the SAME body side by
side and requires `kind`, `len`, `info`, `flags`, the literal payloads, `sym`
and `typ` to agree at every node of every routine body in the dependency
closure. The `PNode` is the oracle, so it compares everything rather than what
someone thought to check. It found two bugs, both silent:
* `BNode.typ` answered `nil` for every bare `Symbol`. `ast.typ` does not: it
falls back to `n.sym.typ` when the loader set `nfLazyType`, which it does for
exactly that shape. The consequence is not less information but a DIFFERENT
answer — `canRaise` asks `fn.typ.kind == tyProc` about a call's callee, so
nil turns "this call can raise" into "it cannot" and drops the
goto-exception check after the call.
* `(ht . <sym>)` — an explicitly nil node type — made `n.typ` LOAD-ORDER
DEPENDENT in the loader itself. `newSymNode` marks the node lazy only if the
symbol was still an unloaded stub at that moment, so the same `.bif` node
answered `sym.typ` or `nil` depending on what happened to touch that symbol
first. Pinned to the lazy reading, so the answer is a property of the file
rather than of the traversal order.
With `typ` correct, the blocker recorded in `allPathsAsgnResult` is gone.
`ast.canRaise`/`canRaiseConservative` cannot become `AnyNode` procs where they
live — `BNode` is defined in `bnode.nim`, which imports `ast` — so their bodies
move into templates that `bnode` instantiates for its own node type. One source
of truth, no cycle, no second copy. `ccgcalls.canRaiseDisp` and
`cgen.allPathsAsgnResult` follow.
Adds the leaf accessors (`intVal`, `floatVal`, `strVal`, `ident`, `flags`)
because nothing in `ccgexprs` can migrate without them, and `rawDesc` for
diagnosing a disagreement in terms of what the token stream literally says.
`compiler/bodynav.nim` replaces the `BodyScope` snapshot with a scope chain the
traversal maintains — `openScope`/`closeScope`/`registerDefHere`, lookup
falling through to the decoder — ported from Nimony's `typenav`. The scope
becomes a product of the walk, so nothing is copied ahead of time and nothing
can be stale. How much of a live problem the snapshot was is measured rather
than assumed: `-d:icLocalSymStats` reports `localHit=0 fieldStub=2 miss=0
sdReg=5902 extractReg=45` over the stdlib closure, i.e. definitions register
constantly and not one use ever resolved through the table, because
`isLocalSym` is a hardwired `false`. The hazard was latent; this keeps it
latent once that stops being true.
Verified: 0 disagreements over the whole `--ic:on` closure with the walk
driving the nav; deliberately breaking `intVal`, `flags` and the nav key each
make the grinder fire on the first bodies it reaches, so the clean run is not
vacuous; the default path emits 215/215 byte-identical `.c` against the
pre-change compiler and does not compile `bodynav` at all; `tests/ic` 39/39.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01XEF7FJvUkGKvG9LSGuEaNR
5799220c98