Fix "entries seen" chip double-counting on reserved rows

[halaprix]

The bug

A single history.push(7) in a constructor reports "2 entries seen" on the
history reserved row, not 1.

Root cause

runtimeView.ts's derivedCountByBase counted distinct resolution labels
grouped by baseVariable. A dynamic array's push touches two storage slots
under the same baseVariable ("history"):

1. the declared length slot itself — read on entry, rewritten on exit, labeled
   history.length by resolveReferenceBaseSlot;
2. the actual new element, at a keccak-derived slot, labeled history[0].

Both got counted as if they were derived entries, so the label-based count always
overcounted a push by exactly one — the reserved slot's own bookkeeping access was
mistaken for a second entry.

The fix

derivedRows.ts's buildDerivedChildren — added in v1.4 for the child-row
rendering — already solves this correctly: it explicitly excludes a variable's own
declared slot from the derived set (if (declaredSlots.has(slot)) continue),
counting only slots that are genuinely keccak-derived. StorageGrid.tsx already
computes that exact list per row as children (it drives the rendered child rows).
The chip now reads children.length instead of the separate, buggy
derivedCountByBase mechanism — one source of truth, so the chip and the rows can
never disagree.

Bonus fix, same root cause: this also resolves the struct-nesting gap flagged
when v1.4 shipped. derivedCountByBase keyed on baseVariable (a name), which
never matched a mapping declared inside a struct (s.m vs baseVariable: "m").
byParentSlot keys on the actual slot number, so it's correct regardless of
nesting.

derivedCountByBase was used nowhere else, so it's removed entirely along with its
now-obsolete unit test, rather than left as a second, disagreeing mechanism.

Verification

Reproduced the exact reported scenario as an e2e assertion first (confirmed it
failed against the old code — showed "2 entries seen" — before applying the fix),
then verified green after:

'a reserved slot shows the value the constructor put in it' — history.push(7)
  now asserts: contains '1 entry seen', does not contain '2 entries seen'

Gate	Result
format:check, lint, typecheck	clean
test:unit	240/240
test:e2e (storage.spec.ts)	10/10
test:e2e (full suite)	62/62
fixtures:verify	no drift
release:verify	passed
build:check	226 KB main entry

🤖 Generated with Claude Code

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated (UTC)
slotscope	Ready	Preview	Jul 31, 2026 1:30pm