Hojun-Cho
39432f717c
A tuple LITERAL with a declared-tagged element reached the cursor-fill
helper (cg_tuple_lit_to_cursor) through the generic cgexpr(N_TUPLE) arm
with no declared type, so the element was stored stamped-keyed at its
constructed scalar width rather than widened into the declared tagged box.
Both consumers ran silent and wrong on both stages (#263 gate-blind:
cs==ww byte-identical, both wrong — runtime is the only net).
#64 massign: N_MASSIGN derives a declared tuple type from the lvalue
binding types and threads it into cg_tuple_lit_to_cursor + the receive
loop (mirror of the #57 N_LET wire); a `_` target falls back to the rhs
literal element type for cursor stride.
#68 call-arg: the send is made param-aware (fill over the PARAM tuple) and
the restage guard graduates a declared-tagged element to a real widen
(reusing cg_widen_tagged_store); nested tuple/struct/array elements and
tagged elements with no param decl stay rule-7 loud. The matching
pop/drain is made param-aware too so push count == pop count: a
param-aware send pushes the box's N words, so the drain must pop N or the
SysV arg sequence skews. This is a push/pop balance requirement of the
send change, not a separate latent under-drain (the standalone trailing-
arg drain is already correct at HEAD).
Closed by construction: the only remaining cg_tuple_lit_to_cursor caller
passing NULL/nil is the generic cgexpr(N_TUPLE) arm, provably non-widening
(constructed type == governing type). The four widening consumers — LET,
RETURN, MASSIGN, call-arg — are all decl-wired. Whole-tuple single-ident
reassign from a tuple literal is rule-7 loud (task #49), not a silent
widening consumer, so the residual NULL arm stays non-widening.
Pin: 945_tuple_lit_declblind_run — massign / call-arg / `_`-control /
call-arg-drain / nested-tuple-ERR rows, each base-fail at abd97e6 and
post-pass with cs==ww byte-id.