Item 1 off the SESSION-23 list. T48 proved the lever by hand on the exemplar, T50 located the same
blocker in every sibling; this builds the tool, measures the population, applies it fleet-wide, and
gates it. It BANKS NOTHING — it removes the blocker. The sweep is the next task.
MEASURED BEFORE BUILDING (R35). The blocker census over all 132 still-stubbed siblings is perfectly
uniform: 132/132 carry it, 3 contested symbols each, EXACTLY ONE file-scope decl statement per
(TU, sym), ZERO file-scope references below the decl (so the deletion is always safe), 660
block-scope re-declarations needed.
THE TOOL: tools/scope_tu_externs.py — the TU-side complement of scope_data_externs.py (§8d). §8d
fixes the incoming DRAFT and has a give-up branch that DROPS the draft's own decl when the TU already
declares the symbol at file scope. Right when the types agree; fatal when the byte-true draft needs a
different one — which is exactly how 132 byte-true siblings gate-failed wearing a codegen wall's
costume. This moves the TU's OWN file-scope decl down into every later function that references the
symbol and lacks its own block-scope decl, then deletes the file-scope line.
FILE(u8 D_x) ... then BLOCK(u16 *D_x) below it -> conflicting types (the 132 failures)
(no file-scope decl) ... BLOCK(u8) ... BLOCK(u16 *) -> builds; each fn owns its own view
- contested set DERIVED, never hand-listed (R33): the remapped draft's block-scope D_ externs
intersected with the TU's file-scope decls above the splice point; --family does it per sibling
- built on cdecl.split_statements/_mask (R33), not a 7th regex: depth-0 spans (a fn definition
flushes at its closing '}' — a column-0 test is NOT a file-scope test, m2c emits goto labels at
column 0 inside bodies) + length-preserving comment/string masking. That masking is what kills the
comment-scanning false-positive class still open as item 3.
- REFUSES LOUDLY, never skips silently (R32): >1 file-scope decl above the splice point; a
file-scope statement below the decl referencing the symbol; an unlocatable body brace
- coverage asserted as a DELTA (R32): file-scope -1, block-scope +len(consumers). An absolute
"a block-scope decl exists" check would have passed VACUOUSLY — these TUs already carry ~18
legitimate block-scope decls of the same symbols
VERIFIED IN TWO STEPS (T48's structure — why a 132-file edit was safe to make):
1. the move ALONE on ov_SC01_000 -> make build -> 9052dc0e BYTE-IDENTICAL, then reverted
2. fleet-wide -> R22 clean-fleet (make clean && extract-all && check-all) -> 140 passed, 0 failed
of 140; make tools-health OK (corpus 0 PHANTOM + 0 TRUNCATED, cdecl, audit-binaries,
report/lint/dedup 1886/0). Metrics UNCHANGED at 85.5% instr / 76.1% distinct / 90.62% fn-count
— the correct result for a declaration-only change.
The diff is uniform to the line: all 132 files +11/-3. A second --family run reports 132
nothing-to-do, 0 refused (idempotent).
Deliberately NOT done: wiring this as an automatic jtbl_family_bank stage. That waits until the
sweep measures the payoff — folding an unproven pre-pass into the gate is the same unmeasured
premise this phase keeps catching.
Also preserves .run/near6/g5260_a.c (the T48 raw crack body, allowlisted) — the sweep may need it
for --raw.
cookbook §103 + SETUP tool-inventory row (R21).
Drew T
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