From 9bd0d8bc8127e19965148c03e15ac60195501c63 Mon Sep 17 00:00:00 2001
From: Hojun-Cho <ghwns6743@gmail.com>
Date: Fri, 5 Jun 2026 11:52:08 +0900
Subject: [PATCH] wcc: #5 F1 promote type_chase_named + transitive-peel
 acceptance align-cs-up
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Promote type_chase_named from cmd/w6c/cgen.c (static) to cmd/wcc/type.c
(exported via ww.h) and re-route every checker single-NAMED-peel through
it: check.c's ~28 inline ternaries + 3 ad-hoc loops, type.c's
assignability/untyped/borrow/opaque peels. type_eq's nominal identity
(check.c:114) and the resolve machinery guards stay untouched.

The re-route IS the acceptance align-up — cstage loud-rejected alias
shapes wwstage accepts AND runs Hare-right (F0 census, harec dealiases
at every consumer):
- #54 binop alias-vs-base: unify_arith gains the harec type_promote arm
  (ref/harec/src/check.c:1083-1105) — one-sided alias + dealias-equal
  promotes to the ALIAS side; alias-vs-alias stays rejected.
- alias-cond family: if/for/&&/||/! chase-then-bool (harec
  check.c:2141/2515/3229/3572). assert stays loud (F0 2a symmetric).
- #70 field access through 2-level alias chains (ken c3_chain3).
- assignability through the full chain (harec types.c:989-996
  dealias-both): return/init/assign legs, F0 8b idx/slice walls.
- alias-of-ptr deref (harec types.c:19-22 type_dereference).

The widening reaches cgen arms whose own single peels then misbehaved —
both classes are closed IN THIS COMMIT so no intermediate state ships a
loud->silent flip (bisect no-silent invariant):
- index family: the 8b acceptance hit ptr-load base + esz=1 (SEGV /
  prefix-luck) — idx_eff + the N_INDEX read / index-write / &base[i] /
  N_SLICE (expr + call-arg) / N_FORRANGE / aggarg_srcaddr-index /
  castsrcprim-dot / match-field base classifies chase.
- kind classifiers (ken #61-root-verify v3 find): a 2-level f64 alias
  param reached cg_isfloat's single peel and classified INT — silent
  wrong-register-class. cg_isfloat / type_isf32 / fld_isfloat /
  type_isstr / type_isslice chase. ken's v3 row is pinned with credit.

Bootstrap asm is byte-identical before/after (w6c on every
main.combined.ww cmp-equal vs a pristine 738d7f4 scratch; 989
lib_byteid pins unchanged): 2-level chains were checker-walled pre-F1,
so no previously-accepted program changes shape.

test: 944_alias_accept_run (20 rows): acceptance graduations pinned
runtime + byte-id both stages; idx/slice/range/slice-param rows cs-only
until the wwstage #60 esz family lands (F2 batch 1); cs-only
harec-parity loud pin for alias-vs-alias binop; assert stays-loud row;
ken-v3 + f64/str/slice kind rows. Mutation-checked at 738d7f4.

reviewer-F1 fold — the same invariant, outside the F0 census: this
commit ADMITS 2+-level alias slice/str/aggregate types in STRUCT FIELD
position, therefore this commit must keep them correct-or-loud. The
cgen FIELD-TYPE gates single-peeled, so the slice/str 3-word arms fell
to word0-only scalar tails — accept-and-corrupt, ww correct, every
shape loud at the pristine base. Chased (probe-proven, byte-id
graduations): single-dot field store + via-ptr twin, struct-lit fill,
chained store-walk LEAF (the #71 walk chases hops, not leaves),
chained-ptr-field store, single-dot / via-ptr / chained-walk field
reads (clobber-probed — word0 reads luck-passed on stale BX/CX). The
six unprobed sibling gates (indexed-elem store/read, ptr-chain read,
heap fill, tuple-elem read, static emit) hard-error via
fld_alias_tripwire on a 2+-level alias over an aggregate base, citing
task #73 (the family's scheduled chase); <=1-level and scalar bases
never fire — zero behavior change for any pre-#5-legal program (five
selfhost mains cmp-identical vs the pristine 738d7f4 scratch).
test: 944 +11 rows (9 K_RUN byte-id, wholeread K_RUN_CS [#60 ww half +
pre-existing 1-level read-spine divergence], #73 tripwire
K_BUILDERR_CS pin); 1-level controls per gate in /tmp/revF1.
---
 Makefile                        |   7 +
 cmd/w6c/cgen.c                  | 165 +++++---
 cmd/wcc/check.c                 | 148 ++++---
 cmd/wcc/type.c                  |  63 ++-
 cmd/wcc/ww.h                    |   1 +
 test/wcc/944_alias_accept_run.c | 711 ++++++++++++++++++++++++++++++++
 6 files changed, 955 insertions(+), 140 deletions(-)
 create mode 100644 test/wcc/944_alias_accept_run.c

diff --git a/Makefile b/Makefile
index edeee030..01bf67c3 100644
--- a/Makefile
+++ b/Makefile
@@ -303,6 +303,7 @@ TESTS	= $(BIN)/test_smoke $(BIN)/test_lex $(BIN)/test_parse $(BIN)/test_check \
 	  $(BIN)/test_subslice_ptresz_run \
 	  $(BIN)/test_deref_slice_store_run \
 	  $(BIN)/test_alias_decl_order_size_run \
+	  $(BIN)/test_alias_accept_run \
 	  $(BIN)/test_tuple_nary_destructure_run \
 	  $(BIN)/test_rvalue_tuple_destructure_run \
 	  $(BIN)/test_overcap_tuple_field_store_run \
@@ -1453,6 +1454,12 @@ $(BIN)/test_alias_decl_order_size_run: test/wcc/944_alias_decl_order_size_run.c
 		$(LIB)/libwwrt.a | $(BIN)
 	$(CC) $(CFLAGS) -o $@ $<
 
+$(BIN)/test_alias_accept_run: test/wcc/944_alias_accept_run.c \
+		$(BIN)/ww $(BIN)/w6c $(BIN)/w6a $(BIN)/w6l \
+		$(BIN)/ww_ww $(BIN)/w6c_ww $(BIN)/w6a_ww $(BIN)/w6l_ww \
+		$(LIB)/libwwrt.a | $(BIN)
+	$(CC) $(CFLAGS) -o $@ $<
+
 $(BIN)/test_tuple_nary_destructure_run: test/wcc/945_tuple_nary_destructure_run.c \
 		$(BIN)/ww $(BIN)/w6c $(BIN)/w6a $(BIN)/w6l \
 		$(BIN)/ww_ww $(BIN)/w6c_ww $(BIN)/w6a_ww $(BIN)/w6l_ww \
diff --git a/cmd/w6c/cgen.c b/cmd/w6c/cgen.c
index ce05fabb..537d6752 100644
--- a/cmd/w6c/cgen.c
+++ b/cmd/w6c/cgen.c
@@ -176,25 +176,18 @@ static int nyields;
 static int
 cg_isfloat(Type *t)
 {
-	if (t == NULL) return 0;
-	if (t->kind == TY_NAMED) t = t->under;
+	/* Transitive chase (#5 F1): the acceptance align opened 2-level
+	 * float/str/slice aliases to these kind classifiers — a single
+	 * peel mis-classed them scalar/INT (ken v3: f64-alias param read
+	 * the wrong register class once the checker admitted it). */
+	t = type_chase_named(t);
 	if (t == NULL) return 0;
 	return t->kind == TY_F32 || t->kind == TY_F64
 	    || t->kind == TY_UNTYPED_FLOAT;
 }
 
-/* type_chase_named — walk the TY_NAMED.under chain to the deepest non-
- * named type. Chain-of-aliases (#22): `type b = a; type a = struct;`
- * stacks two TY_NAMED layers — a single peel leaves `t` pointing at
- * the inner alias (still TY_NAMED), so kind-gated arms (TY_STRUCT,
- * TY_SLICE, TY_TAGGED, TY_PTR) miss and the codegen silently falls
- * through to a scalar shape. Mirror of wwstage's structlookupchain. */
-static Type *
-type_chase_named(Type *t)
-{
-	while (t && t->kind == TY_NAMED) t = t->under;
-	return t;
-}
+/* type_chase_named lives in cmd/wcc/type.c since the #5 alias arc — the
+ * checker's acceptance sites share the transitive peel with cgen. */
 
 /* cg_sret_retsize — sret classifier; defined after the tuple register-
  * return helpers (tuple_rseq / tuple_eslot / fld_isfloat) it consults
@@ -211,8 +204,7 @@ node_isfloat(Node *n)
 static int
 type_isstr(Type *t)
 {
-	if (t == NULL) return 0;
-	if (t->kind == TY_NAMED) t = t->under;
+	t = type_chase_named(t);
 	if (t == NULL) return 0;
 	return t->kind == TY_STR || t->kind == TY_UNTYPED_STR;
 }
@@ -226,8 +218,7 @@ node_isstr(Node *n)
 static int
 type_isslice(Type *t)
 {
-	if (t == NULL) return 0;
-	if (t->kind == TY_NAMED) t = t->under;
+	t = type_chase_named(t);
 	return t && t->kind == TY_SLICE;
 }
 
@@ -317,8 +308,7 @@ tuple_eslot(Type *t)
 static int
 type_isf32(Type *t)
 {
-	if (t == NULL) return 0;
-	if (t->kind == TY_NAMED) t = t->under;
+	t = type_chase_named(t);
 	return t && t->kind == TY_F32;
 }
 
@@ -350,8 +340,7 @@ static int
 fld_isfloat(Type *t, int *isf32)
 {
 	if (isf32) *isf32 = 0;
-	if (t == NULL) return 0;
-	if (t->kind == TY_NAMED) t = t->under;
+	t = type_chase_named(t);
 	if (t == NULL) return 0;
 	if (t->kind == TY_F64) return 1;
 	if (t->kind == TY_UNTYPED_FLOAT) return 1;
@@ -444,6 +433,32 @@ fldstoreop(Type *t, int sz)
 	return A_MOVQ;
 }
 
+/* fld_alias_tripwire — #73 guard at the single-peel field gates this
+ * fold did NOT chase. The #5-F1 acceptance admits 2+-level alias field
+ * types everywhere; a still-NAMED type after one peel skips a gate's
+ * multi-word arms (slice/str 3-word, tagged widener, struct copy) for
+ * a word0 scalar tail — accept-and-corrupt. Loud over silent (rule 7);
+ * chase + per-arm probes are task #73. Fires ONLY on 2+-level chains
+ * over an aggregate base: <=1-level (the entire pre-#5-F1-legal set)
+ * and scalar/float bases (width-driven tails, depth-safe) never fire. */
+static void
+fld_alias_tripwire(Type *ft, const char *site)
+{
+	Type *u = (ft && ft->kind == TY_NAMED) ? ft->under : ft;
+	if (u == NULL || u->kind != TY_NAMED) return;
+	Type *base = type_chase_named(u);
+	if (base == NULL) return;
+	switch (base->kind) {
+	case TY_SLICE: case TY_STR: case TY_TAGGED:
+	case TY_STRUCT: case TY_TUPLE: case TY_ARRAY:
+		fatal("%s: 2+-level alias field type '%s' at unswept "
+		    "single-peel gate (#73)", site,
+		    ft->name ? ft->name : "?");
+	default:
+		return;
+	}
+}
+
 /* castsrcprim — structural (size, unsigned) of an N_CAST's source
  * expression, mirroring wwstage's exprprimresolved in
  * selfhost/cmd/wcc/cgenutil.ww. The cgen-stage match has to be
@@ -502,11 +517,9 @@ castsrcprim(Node *n, int *sz, int *unsignd)
 		/* Real struct field only. .len / .cap / .ptr on str /
 		 * slice / array are pseudo-fields wwstage doesn't see. */
 		Type *bt = n->lhs ? n->lhs->type : NULL;
-		Type *bu = (bt && bt->kind == TY_NAMED) ? bt->under : bt;
-		if (bu && bu->kind == TY_PTR) {
-			Type *st = bu->sub;
-			bu = (st && st->kind == TY_NAMED) ? st->under : st;
-		}
+		Type *bu = type_chase_named(bt);
+		if (bu && bu->kind == TY_PTR)
+			bu = type_chase_named(bu->sub);
 		if (bu && bu->kind == TY_STRUCT) {
 			t = n->type;
 		}
@@ -1250,9 +1263,12 @@ static Type *
 idx_eff(Type *t)
 {
 	if (t == NULL) return NULL;
-	Type *u = type_unwrap(t);
+	/* Transitive chase (#5 alias arc): the checker now admits index
+	 * bases through 2-level alias chains (F0 8b); a single unwrap left
+	 * eff TY_NAMED → sub NULL → esz=1 byte loads off the chain. */
+	Type *u = type_chase_named(t);
 	if (u && u->kind == TY_PTR && u->sub) {
-		Type *p = type_unwrap(u->sub);
+		Type *p = type_chase_named(u->sub);
 		if (p && p->kind == TY_ARRAY) return p;
 	}
 	return u;
@@ -2100,7 +2116,7 @@ aggarg_srcaddr(Cg *c, Node *src, int dst, Local *locals)
 		Node *base = src->lhs;
 		Node *idx = src->rhs;
 		Type *bt = base ? base->type : NULL;
-		Type *bu = (bt && bt->kind == TY_NAMED) ? bt->under : bt;
+		Type *bu = type_chase_named(bt);
 		if (base && base->kind == N_IDENT && bu
 		    && bu->kind == TY_ARRAY) {
 			int esz = (bu->sub) ? (int)bu->sub->size : 1;
@@ -3032,7 +3048,11 @@ cg_structlit_fill(Cg *c, Local **locals_p, Type *lu, Node *lit,
 				break;
 			}
 		}
-		Type *fu = (ft && ft->kind == TY_NAMED) ? ft->under : ft;
+		/* Transitive chase (#5-F1 fold): a 2-level-alias slice/str
+		 * field fell past every kind arm to the word0-only scalar
+		 * tail — silent, reachable only via this commit's
+		 * acceptance (reviewer-F1 s1 probe). */
+		Type *fu = type_chase_named(ft);
 		if (fu && fu->kind == TY_TAGGED) {
 			/* Tagged store: reload BX first (if non-BP) so the
 			 * widener sees a valid base reg. The widener itself
@@ -4132,8 +4152,7 @@ cgexpr(Cg *c, Node *n, Local *locals)
 				Node *base = opnd->lhs;
 				Node *idx = opnd->rhs;
 				Type *bt = base ? base->type : NULL;
-				Type *bu = (bt && bt->kind == TY_NAMED)
-				    ? bt->under : bt;
+				Type *bu = type_chase_named(bt);
 				Type *eff = idx_eff(bt);
 				int esz = (eff && eff->sub)
 				    ? (int)eff->sub->size : 1;
@@ -4703,8 +4722,11 @@ cgexpr(Cg *c, Node *n, Local *locals)
 				 *     work cleanly.
 				 *   - else: struct local, BP-relative. */
 				Type *ft = f->type;
-				Type *fu = (ft && ft->kind == TY_NAMED)
-				    ? ft->under : ft;
+				/* Transitive chase (#5-F1 fold): 2-level alias
+				 * slice/str field skipped the 3-word arm — ptr
+				 * word stored, len/cap dropped (reviewer-F1
+				 * ix2/s2/s3 probes; c1-acceptance-reached). */
+				Type *fu = type_chase_named(ft);
 				/* Tagged-union field — full slot rewrite via the
 				 * shared widener so every rhs shape (whole-tagged
 				 * ident or expr with tag-remap, concrete-variant
@@ -4749,8 +4771,7 @@ cgexpr(Cg *c, Node *n, Local *locals)
 				int is_global = (boff == 0 && !via_ptr
 				    && let_islet(base->str));
 				int foff = (int)f->offset;
-				Type *str_fu = (f->type && f->type->kind == TY_NAMED)
-				    ? f->type->under : f->type;
+				Type *str_fu = type_chase_named(f->type);
 				/* str/slice field: str IS []u8, so both store the full
 				 * 3-word {ptr,len,cap} that rhs cgexpr leaves in
 				 * (AX,BX,CX) at field+0/+8/+16. Address scratch must
@@ -5025,6 +5046,8 @@ cgexpr(Cg *c, Node *n, Local *locals)
 					if (f != NULL && (is_arr || is_sl || is_ptr)
 					    && off != 0) {
 						Type *ft = f->type;
+						fld_alias_tripwire(ft,
+						    "indexed-elem field store");
 						Type *fu = (ft && ft->kind == TY_NAMED)
 						    ? ft->under : ft;
 						int fsz = (int)(ft ? ft->size : 8);
@@ -5272,8 +5295,11 @@ cgexpr(Cg *c, Node *n, Local *locals)
 						{ f = fl; break; }
 					if (f != NULL) {
 						Type *ft = f->type;
-						Type *fu = (ft && ft->kind == TY_NAMED)
-						    ? ft->under : ft;
+						/* Transitive chase (#5-F1 fold):
+						 * 2-level alias slice/str field
+						 * skipped the 3-word arm
+						 * (reviewer-F1 p1 probe). */
+						Type *fu = type_chase_named(ft);
 						int fsz = (int)(ft ? ft->size : 8);
 						int store_op = fldstoreop(ft, fsz);
 						int foff = (int)f->offset;
@@ -5576,9 +5602,12 @@ cgexpr(Cg *c, Node *n, Local *locals)
 							}
 							break;
 						}
-						Type *fu = (leaf_type
-						    && leaf_type->kind == TY_NAMED)
-						    ? leaf_type->under : leaf_type;
+						/* Transitive chase (#5-F1 fold): the walk
+						 * HOPS chase (#71) but the LEAF gate
+						 * single-peeled — 2-level alias slice leaf
+						 * fell to the scalar tail (reviewer-F1 s4
+						 * probe). */
+						Type *fu = type_chase_named(leaf_type);
 						int fsz = (int)(leaf_type
 						    ? leaf_type->size : 8);
 						int store_op = fldstoreop(leaf_type, fsz);
@@ -5881,7 +5910,7 @@ cgexpr(Cg *c, Node *n, Local *locals)
 		if (n->lhs->kind == N_INDEX && n->lhs->lhs && !place_slit) {
 			Node *base = n->lhs->lhs;
 			Type *bt = base->type;
-			Type *u = (bt && bt->kind == TY_NAMED) ? bt->under : bt;
+			Type *u = type_chase_named(bt);
 			int is_arr = u && u->kind == TY_ARRAY;
 			int is_sl  = u && u->kind == TY_SLICE;
 			int is_ptr = u && u->kind == TY_PTR;
@@ -7805,6 +7834,8 @@ cgexpr(Cg *c, Node *n, Local *locals)
 					 * CX=cap). Route the heap base through DX so all
 					 * three survive — CX now holds cap, BX holds len
 					 * (#1/Phase 3). */
+					fld_alias_tripwire(ftype,
+					    "heap struct-lit field fill");
 					Type *fu = (ftype && ftype->kind == TY_NAMED)
 					    ? ftype->under : ftype;
 					if (fu && fu->kind == TY_STR) {
@@ -8642,8 +8673,7 @@ cgexpr(Cg *c, Node *n, Local *locals)
 				Node *lo = args[i]->rhs;
 				Node *hi = args[i]->cond;
 				Type *bt = base ? base->type : NULL;
-				Type *bu = (bt && bt->kind == TY_NAMED) ?
-				    bt->under : bt;
+				Type *bu = type_chase_named(bt);
 				/* esz from the type table for an N_IDENT base
 				 * (#76) or an N_DOT array/slice-field base
 				 * (#257: scale by the field's element width via
@@ -9394,7 +9424,7 @@ cgexpr(Cg *c, Node *n, Local *locals)
 			 * value words at +8/+16) is contiguous within the struct,
 			 * so no spill is needed. */
 			Type *bt = s->lhs->type;
-			Type *bu = (bt && bt->kind == TY_NAMED) ? bt->under : bt;
+			Type *bu = type_chase_named(bt);
 			Tfield *f = NULL;
 			if (bu && bu->kind == TY_STRUCT) {
 				for (Tfield *fl = bu->fields; fl; fl = fl->next) {
@@ -10372,9 +10402,11 @@ cgexpr(Cg *c, Node *n, Local *locals)
 								    areg(D_AX));
 								goto dot_done;
 							}
-							Type *fu = (leaf_type
-							    && leaf_type->kind == TY_NAMED)
-							    ? leaf_type->under : leaf_type;
+							/* Transitive chase (#5-F1 fold):
+							 * read twin of the store-walk
+							 * leaf gate (reviewer-F1 r2b
+							 * clobber probe). */
+							Type *fu = type_chase_named(leaf_type);
 							/* tagged leaf (#38a): load the box into
 							 * the tagged cursor (AX=tag, DX=val0,
 							 * R8=val2 before CX=val1 — base_reg may
@@ -10588,6 +10620,8 @@ cgexpr(Cg *c, Node *n, Local *locals)
 			}
 			if (tp != NULL) {
 				int fsz = (int)(tp->type ? tp->type->size : 8);
+				fld_alias_tripwire(tp->type,
+				    "tuple-elem read");
 				Type *fu = (tp->type && tp->type->kind == TY_NAMED)
 				    ? tp->type->under : tp->type;
 				int op = fldloadop(tp->type, fsz);
@@ -10742,8 +10776,12 @@ cgexpr(Cg *c, Node *n, Local *locals)
 				 * folds onto the slice arm (#1/Phase 3 collapse).
 				 * base_reg may be CX for globals; load .cap LAST so
 				 * the base survives the earlier reads. */
-				Type *str_fu = (f->type && f->type->kind == TY_NAMED)
-				    ? f->type->under : f->type;
+				/* Transitive chase (#5-F1 fold): the slice half
+				 * single-peeled while the str half (type_isstr)
+				 * recursed — a 2-level alias slice field read
+				 * loaded ptr only, len/cap rode stale registers
+				 * (reviewer-F1 r1b clobber probe). */
+				Type *str_fu = type_chase_named(f->type);
 				if ((str_fu && str_fu->kind == TY_SLICE) ||
 				    type_isstr(f->type)) {
 					ins2(c, A_MOVQ,
@@ -10860,8 +10898,10 @@ cgexpr(Cg *c, Node *n, Local *locals)
 					 * pointer, so load .len LAST — the earlier loads
 					 * still index off the original base. str folds
 					 * onto the slice arm (#1/Phase 3 collapse). */
-					Type *str_fu = (f->type && f->type->kind == TY_NAMED)
-					    ? f->type->under : f->type;
+					/* Transitive chase (#5-F1 fold): via-ptr twin
+					 * of the BP-base read gate (reviewer-F1 r3
+					 * clobber probe). */
+					Type *str_fu = type_chase_named(f->type);
 					if ((str_fu && str_fu->kind == TY_SLICE) ||
 					    type_isstr(f->type)) {
 						ins2(c, A_MOVQ,
@@ -10913,6 +10953,8 @@ cgexpr(Cg *c, Node *n, Local *locals)
 						if (strcmp(f->name, n->str) != 0) continue;
 						cgexpr(c, n->lhs, locals);	/* AX = inner ptr */
 						Type *ft = f->type;
+						fld_alias_tripwire(ft,
+						    "ptr-chain field read");
 						Type *fu = (ft && ft->kind == TY_NAMED)
 						    ? ft->under : ft;
 						/* tagged leaf (#38a): AX holds the *struct
@@ -11070,6 +11112,8 @@ cgexpr(Cg *c, Node *n, Local *locals)
 						    areg(D_AX));
 					int foff = (int)f->offset;
 					Type *ft = f->type;
+					fld_alias_tripwire(ft,
+					    "indexed-elem field read");
 					Type *fu = (ft && ft->kind == TY_NAMED)
 					    ? ft->under : ft;
 					/* #270-1a: an `[N]T`-typed field of an
@@ -11232,7 +11276,7 @@ cgexpr(Cg *c, Node *n, Local *locals)
 		    && let_islet(n->lhs->str)) {
 			bt = let_var_type(n->lhs->str);
 		}
-		Type *u = (bt && bt->kind == TY_NAMED) ? bt->under : bt;
+		Type *u = type_chase_named(bt);
 		Type *eff = idx_eff(bt);
 		int esz = 1;
 		if (eff && eff->sub) esz = (int)eff->sub->size;
@@ -11419,7 +11463,8 @@ cgexpr(Cg *c, Node *n, Local *locals)
 		Node *lo = n->rhs;
 		Node *hi = n->cond;
 		Type *bt = base ? base->type : NULL;
-		Type *bu = (bt && bt->kind == TY_NAMED) ? bt->under : bt;
+		/* Transitive chase (#5 alias arc) — see the N_INDEX twin. */
+		Type *bu = type_chase_named(bt);
 		/* esz from the type table for an N_IDENT base (#76) or an
 		 * N_DOT array/slice-field base (#252: a struct-field slice
 		 * `s.obuf[lo:hi]` must scale by the field's element width, not
@@ -13173,10 +13218,13 @@ cgstmt(Cg *c, Node *n, Local **locals, int *frame)
 		 * or pulls each tuple field into its respective local. */
 		Node *slc = n->lhs;
 		Type *st = slc ? slc->type : NULL;
-		Type *u = (st && st->kind == TY_NAMED) ? st->under : st;
+		/* Transitive chase (#5 alias arc): the checker admits range
+		 * bases through 2-level alias chains (F0 8b); the single peel
+		 * left u TY_NAMED → esz=1 + the non-array base arm (MOVQ of
+		 * array words as a pointer — SEGV). */
+		Type *u = type_chase_named(st);
 		int esz = (u && u->sub) ? (int)u->sub->size : 1;
-		Type *etu = (u && u->sub && u->sub->kind == TY_NAMED)
-		    ? u->sub->under : (u ? u->sub : NULL);
+		Type *etu = type_chase_named(u ? u->sub : NULL);
 		int destruct = (n->list != NULL);
 
 		/* allocate temp slots: _i (8B), _len (8B). #70: a NON-IDENT
@@ -14191,6 +14239,7 @@ emit_struct_lit_bytes(FILE *out, Cg *c, Type *t, Node *rhs, u64 base)
 		}
 		Node *vr = v;
 		while (vr != NULL && vr->kind == N_CAST) vr = vr->lhs;
+		fld_alias_tripwire(f->type, "static struct-lit emit");
 		Type *fu = (f->type && f->type->kind == TY_NAMED)
 		    ? f->type->under : f->type;
 		if (fu && fu->kind == TY_STRUCT) {
diff --git a/cmd/wcc/check.c b/cmd/wcc/check.c
index 749f3998..4885a0b9 100644
--- a/cmd/wcc/check.c
+++ b/cmd/wcc/check.c
@@ -344,7 +344,7 @@ addrfn_ptr_matches(Type *ptr, Type *fnty)
 {
 	if (ptr == NULL || ptr->kind != TY_PTR) return 0;
 	Type *ref = ptr->sub;
-	if (ref && ref->kind == TY_NAMED) ref = ref->under;
+	ref = type_chase_named(ref);
 	if (ref == NULL || ref->kind != TY_FN) return 0;
 	return type_eq(ref, fnty);
 }
@@ -377,7 +377,7 @@ assignable_addrfn(Checker *c, Type *dst, Node *rhs)
 	if (s == NULL || s->kind != SK_FN) return 0;
 	Type *fnty = s->type;
 	if (fnty == NULL || fnty->kind != TY_FN) return 0;
-	Type *du = (dst->kind == TY_NAMED) ? dst->under : dst;
+	Type *du = type_chase_named(dst);
 	if (du == NULL) return 0;
 	if (du->kind == TY_PTR) return addrfn_ptr_matches(du, fnty);
 	if (du->kind == TY_TAGGED) {
@@ -408,7 +408,7 @@ static int
 arrlit_init_fits(Checker *c, Type *dt, Node *rhs)
 {
 	if (rhs == NULL || rhs->kind != N_ARRLIT) return 0;
-	Type *u = (dt && dt->kind == TY_NAMED) ? dt->under : dt;
+	Type *u = type_chase_named(dt);
 	/* #25: a SLICE target is admitted via the same per-element coercion
 	 * as the array path — the #258 borrow demands an exact element
 	 * type_eq, which an arrlit's self-stamped [N]<default> can't meet for
@@ -417,7 +417,7 @@ arrlit_init_fits(Checker *c, Type *dt, Node *rhs)
 	if (u == NULL || (u->kind != TY_ARRAY && u->kind != TY_SLICE))
 		return 0;
 	Type *et = u->sub;
-	Type *eu = (et && et->kind == TY_NAMED) ? et->under : et;
+	Type *eu = type_chase_named(et);
 	u64 count = 0;
 	for (Node *e = rhs->list; e; e = e->next) {
 		if (e->kind == N_FIELD && e->str
@@ -705,8 +705,7 @@ resolve_type(Checker *c, Node *n)
 			 * the checker-says-8/cgen-does-16 split behind the
 			 * packed-tuple miscompile family (#32/#33/#48). */
 			if (tp->type) {
-				Type *eu = tp->type->kind == TY_NAMED
-				    ? tp->type->under : tp->type;
+				Type *eu = type_chase_named(tp->type);
 				if (eu && (eu->kind == TY_STR
 				    || eu->kind == TY_SLICE
 				    || eu->kind == TY_TAGGED))
@@ -753,8 +752,7 @@ resolve_type(Checker *c, Node *n)
 			 * (possibly NAMED) inner tagged union into the
 			 * enclosing union — matches Hare's parse-time
 			 * unwrap flag on each tagged_type entry. */
-			Type *vu = spread && vt && vt->kind == TY_NAMED
-			    ? vt->under : vt;
+			Type *vu = spread ? type_chase_named(vt) : vt;
 			if (vu && vu->kind == TY_TAGGED &&
 			    (spread || vt->kind == TY_TAGGED)) {
 				for (Tparam *src = vu->params; src; src = src->next) {
@@ -885,7 +883,7 @@ resolve_type(Checker *c, Node *n)
 			/* embed (anonymous struct or bare-name): the inner type
 			 * must be a struct; its fields are promoted to the outer
 			 * scope with offsets shifted by the embed base. */
-			Type *inner = (ft && ft->kind == TY_NAMED) ? ft->under : ft;
+			Type *inner = type_chase_named(ft);
 			if (inner == NULL || inner->kind != TY_STRUCT) {
 				err(c, f->pos, "embedded type must be a struct");
 				off += ft ? ft->size : 0;
@@ -982,6 +980,27 @@ unify_arith(Checker *c, Pos p, Type *a, Type *b)
 	if (type_isuntyped(a) && type_assignable(b, a)) return b;
 	if (type_isuntyped(b) && type_assignable(a, b)) return a;
 	if (type_eq(a, b)) return a;
+	/* One-sided alias vs its (transitive) base promotes to the ALIAS
+	 * side; alias vs DIFFERENT alias stays rejected even when the
+	 * bases agree. Mirrors harec type_promote (ref/harec/src/check.c:
+	 * 1083-1105: ALIAS+ALIAS → NULL, then dealias-equal → the alias
+	 * operand). wwstage accepts these shapes and runs them on the
+	 * chased width (F0 m1_binop/m1_binop2, ww runtime-correct).
+	 *
+	 * ERROR axis guard: `type invalid = !i32` must NOT promote against
+	 * a plain i32 — type_eq ignores iserror (primitives compare by
+	 * kind), but harec interns flags into DISTINCT types, so flagged-
+	 * vs-unflagged never reaches type_promote's dealias-equal arm. The
+	 * #246 loud (strconv.invalid != i32, pinned by 949_errtype_compare
+	 * on BOTH stages) rides this reject. */
+	{
+		Type *da = type_chase_named(a);
+		Type *db = type_chase_named(b);
+		if (!(a->kind == TY_NAMED && b->kind == TY_NAMED) &&
+		    da && db && da->iserror == db->iserror &&
+		    type_eq(da, db))
+			return (a->kind == TY_NAMED) ? a : b;
+	}
 	return err(c, p, "operands have differing types %s and %s",
 	    type_name(c->a, a), type_name(c->a, b));
 }
@@ -1017,9 +1036,7 @@ coerce_floatlit(Node *n, Type *target)
 		return;
 	/* Chase the full alias chain (wwstage resolvealias does the same), so
 	 * a doubly-aliased f32 target stamps in both stages or neither. */
-	Type *u = target;
-	while (u && u->kind == TY_NAMED)
-		u = u->under;
+	Type *u = type_chase_named(target);
 	if (u == NULL || u->kind != TY_F32)
 		return;
 	if (n->kind == N_FLOATLIT && n->type == ty_untyped_float)
@@ -1054,7 +1071,7 @@ static int
 reject_arrlit_borrow(Checker *c, Type *dst, Node *expr)
 {
 	if (expr == NULL || expr->kind != N_ARRLIT) return 0;
-	Type *du = (dst && dst->kind == TY_NAMED) ? dst->under : dst;
+	Type *du = type_chase_named(dst);
 	if (du == NULL || du->kind != TY_SLICE) return 0;
 	err(c, expr->pos, "array literal cannot borrow as a slice here; "
 	    "bind it to a `let` first");
@@ -1066,9 +1083,8 @@ desugar_arrayslice(Checker *c, Type *dst, Node *expr)
 {
 	if (dst == NULL || expr == NULL || expr->type == NULL)
 		return;
-	Type *du = (dst->kind == TY_NAMED) ? dst->under : dst;
-	Type *su = (expr->type->kind == TY_NAMED) ? expr->type->under
-	    : expr->type;
+	Type *du = type_chase_named(dst);
+	Type *su = type_chase_named(expr->type);
 	if (du == NULL || su == NULL ||
 	    du->kind != TY_SLICE || su->kind != TY_ARRAY)
 		return;
@@ -1119,12 +1135,18 @@ cbinop(Checker *c, Node *n)
 			err(c, n->pos, "ordered comparison on non-numeric");
 		(void)unify_arith(c, n->pos, l, r);
 		return ty_bool;
-	case TK_AND: case TK_OR:
-		if (!(l == ty_bool || l == ty_untyped_bool || l == ty_err))
+	case TK_AND: case TK_OR: {
+		/* Bool-ness through the alias chain — harec dealiases at the
+		 * logical-binop consumer (ref/harec/src/check.c:3229); ww
+		 * accepts + runs the alias-bool operand (F0 m2_andor). */
+		Type *lu = type_chase_named(l);
+		Type *ru = type_chase_named(r);
+		if (!(lu == ty_bool || lu == ty_untyped_bool || l == ty_err))
 			err(c, n->pos, "left of %s is not bool", tokname(n->op));
-		if (!(r == ty_bool || r == ty_untyped_bool || r == ty_err))
+		if (!(ru == ty_bool || ru == ty_untyped_bool || r == ty_err))
 			err(c, n->pos, "right of %s is not bool", tokname(n->op));
 		return ty_bool;
+	}
 	default:
 		return err(c, n->pos, "unsupported binary op %s", tokname(n->op));
 	}
@@ -1139,20 +1161,28 @@ cunop(Checker *c, Node *n)
 		if (!type_isnum(t))
 			return err(c, n->pos, "%s on non-numeric", tokname(n->op));
 		return t;
-	case TK_NOT:
-		if (!(t == ty_bool || t == ty_untyped_bool || t == ty_err))
+	case TK_NOT: {
+		/* harec dealiases at the `!` consumer (ref/harec/src/check.c:
+		 * 3572); ww accepts + runs the alias-bool operand (F0 m2_bang). */
+		Type *u = type_chase_named(t);
+		if (!(u == ty_bool || u == ty_untyped_bool || t == ty_err))
 			err(c, n->pos, "! on non-bool");
 		return ty_bool;
+	}
 	case TK_TILDE:
 		if (!type_isint(t))
 			return err(c, n->pos, "~ on non-integer");
 		return t;
-	case TK_STAR:	/* deref */
+	case TK_STAR: {	/* deref */
 		if (t == ty_err) return ty_err;
-		if (t->kind != TY_PTR)
+		/* harec type_dereference dealiases the operand (ref/harec/src/
+		 * types.c:19-22); wwstage unoptype TK_STAR resolvealias-chases. */
+		Type *u = type_chase_named(t);
+		if (u == NULL || u->kind != TY_PTR)
 			return err(c, n->pos, "cannot deref non-pointer %s",
 			    type_name(c->a, t));
-		return t->sub;
+		return u->sub;
+	}
 	case TK_AMP:	/* address-of */
 		/* Slice/str pseudo-fields .len/.cap surface as i32 but live
 		 * in 8B-aligned slots in the header (ptr@0, len@8, cap@16).
@@ -1165,9 +1195,9 @@ cunop(Checker *c, Node *n)
 		    (strcmp(n->lhs->str, "len") == 0 ||
 		     strcmp(n->lhs->str, "cap") == 0)) {
 			Type *bt = n->lhs->lhs->type;
-			Type *bu = (bt && bt->kind == TY_NAMED) ? bt->under : bt;
+			Type *bu = type_chase_named(bt);
 			if (bu && bu->kind == TY_PTR) bu = bu->sub;
-			if (bu && bu->kind == TY_NAMED) bu = bu->under;
+			bu = type_chase_named(bu);
 			if (bu && (bu->kind == TY_SLICE || bu->kind == TY_STR))
 				return type_ptr(c->a, ty_i64);
 		}
@@ -1269,8 +1299,7 @@ cexpr(Checker *c, Node *n)
 			 * (named) enum type itself, so bitwise ops between
 			 * members yield the same enum type via type_eq. */
 			if (ms && ms->kind == SK_TYPE && ms->type) {
-				Type *u = (ms->type->kind == TY_NAMED)
-				    ? ms->type->under : ms->type;
+				Type *u = type_chase_named(ms->type);
 				if (u && u->kind == TY_ENUM) {
 					for (Tfield *f = u->fields; f; f = f->next) {
 						if (f->name && n->str &&
@@ -1295,9 +1324,9 @@ cexpr(Checker *c, Node *n)
 		}
 		Type *base = cexpr(c, n->lhs);
 		if (base == NULL || base == ty_err) return n->type = ty_err;
-		Type *u = (base->kind == TY_NAMED) ? base->under : base;
+		Type *u = type_chase_named(base);
 		if (u && u->kind == TY_PTR) u = u->sub;
-		if (u && u->kind == TY_NAMED) u = u->under;
+		u = type_chase_named(u);
 		/* Enum member access via a qualified base, e.g. `os.whence.CUR`.
 		 * The inner N_DOT resolved through SK_USE → the SK_TYPE sym's
 		 * named type. Fold the outer access to the member literal. */
@@ -1364,7 +1393,7 @@ cexpr(Checker *c, Node *n)
 		if (idx != ty_err && !type_isint(idx))
 			err(c, n->pos, "index must be integer");
 		if (base == ty_err) return n->type = ty_err;
-		Type *u = (base->kind == TY_NAMED) ? base->under : base;
+		Type *u = type_chase_named(base);
 		if (u && (u->kind == TY_SLICE || u->kind == TY_ARRAY)) {
 			/* #108(b): indexing needs the element size; `[]opaque`
 			 * is a legal (sized) header but its element is unsized.
@@ -1447,9 +1476,9 @@ cexpr(Checker *c, Node *n)
 		    n->list->kind == N_DOT) {
 			Node *dot = n->list;
 			Type *bt = cexpr(c, dot->lhs);
-			Type *u = (bt && bt->kind == TY_NAMED) ? bt->under : bt;
+			Type *u = type_chase_named(bt);
 			if (u && u->kind == TY_PTR) u = u->sub;
-			if (u && u->kind == TY_NAMED) u = u->under;
+			u = type_chase_named(u);
 			u64 off = 0;
 			int found = 0;
 			if (u && u->kind == TY_STRUCT) {
@@ -1544,8 +1573,7 @@ cexpr(Checker *c, Node *n)
 					err(c, n->pos, "delete: operand must be an indexing or slicing expression");
 				else {
 					Type *bt = d->lhs ? d->lhs->type : NULL;
-					while (bt && bt->kind == TY_NAMED)
-						bt = bt->under;
+					bt = type_chase_named(bt);
 					/* harec check.c:2024 wording; a
 					 * fixed-size [N]T base and a str
 					 * base land here. */
@@ -1583,8 +1611,7 @@ cexpr(Checker *c, Node *n)
 					err(c, n->pos, "insert: operand must be an indexing expression xs[i]");
 				else {
 					Type *bt = d->lhs ? d->lhs->type : NULL;
-					while (bt && bt->kind == TY_NAMED)
-						bt = bt->under;
+					bt = type_chase_named(bt);
 					/* harec check.c:807 wording; a
 					 * fixed-size [N]T base lands here. */
 					if (bt == NULL || bt->kind != TY_SLICE)
@@ -1696,7 +1723,7 @@ cexpr(Checker *c, Node *n)
 				(void)cexpr(c, a);
 			return n->type = ty_err;
 		}
-		Type *u = (ft->kind == TY_NAMED) ? ft->under : ft;
+		Type *u = type_chase_named(ft);
 		if (u == NULL || u->kind != TY_FN)
 			return n->type = err(c, n->pos, "calling non-function %s",
 			    type_name(c->a, ft));
@@ -1794,7 +1821,7 @@ cexpr(Checker *c, Node *n)
 		} else {
 			t = resolve_type(c, n->lhs);
 		}
-		Type *u = (t && t->kind == TY_NAMED) ? t->under : t;
+		Type *u = type_chase_named(t);
 		for (Node *f = n->list; f; f = f->next) {
 			Type *vt = cexpr(c, f->lhs);
 			if (u && u->kind == TY_STRUCT) {
@@ -1837,7 +1864,7 @@ cexpr(Checker *c, Node *n)
 		Type *base = cexpr(c, n->lhs);
 		if (n->rhs) (void)cexpr(c, n->rhs);
 		if (n->cond) (void)cexpr(c, n->cond);
-		Type *u = (base && base->kind == TY_NAMED) ? base->under : base;
+		Type *u = type_chase_named(base);
 		if (u && u->kind == TY_ARRAY)
 			return n->type = type_slice(c->a, u->sub);
 		if (u && u->kind == TY_SLICE)
@@ -1856,14 +1883,14 @@ cexpr(Checker *c, Node *n)
 	}
 	case N_RECV: {
 		Type *t = cexpr(c, n->lhs);
-		Type *u = (t && t->kind == TY_NAMED) ? t->under : t;
+		Type *u = type_chase_named(t);
 		if (u && u->kind == TY_CHAN) return n->type = u->sub;
 		return n->type = err(c, n->pos, "<- expects chan, got %s",
 		    type_name(c->a, t));
 	}
 	case N_MATCH: {
 		Type *st = cexpr(c, n->lhs);
-		Type *u = (st && st->kind == TY_NAMED) ? st->under : st;
+		Type *u = type_chase_named(st);
 		if (u == NULL || u->kind != TY_TAGGED) {
 			return n->type = err(c, n->pos,
 			    "match on non-tagged-union %s", type_name(c->a, st));
@@ -1968,13 +1995,13 @@ cexpr(Checker *c, Node *n)
 		 * whether the expression returns bool (is) or the variant
 		 * itself (as). */
 		if (n->rhs) n->rhs->type = vt;
-		Type *u = (t && t->kind == TY_NAMED) ? t->under : t;
+		Type *u = type_chase_named(t);
 		/* Enum ↔ integer cast: `enumval as intT` or `int as enumT`.
 		 * Reinterpret-only — the storage shape is already integer, so
 		 * cgen treats the cast as a no-op (the value lives in the same
 		 * register). The `is` form is rejected; enums aren't sums. */
 		Type *uu = u;
-		Type *vu = (vt && vt->kind == TY_NAMED) ? vt->under : vt;
+		Type *vu = type_chase_named(vt);
 		int lhs_enum = uu && uu->kind == TY_ENUM;
 		int rhs_enum = vu && vu->kind == TY_ENUM;
 		if (n->kind == N_TYPEASSERT && (lhs_enum || rhs_enum) &&
@@ -2012,7 +2039,7 @@ cexpr(Checker *c, Node *n)
 	}
 	case N_TRYPROP: case N_TRYUNW: {
 		Type *t = cexpr(c, n->lhs);
-		Type *u = (t && t->kind == TY_NAMED) ? t->under : t;
+		Type *u = type_chase_named(t);
 		if (u == NULL || u->kind != TY_TAGGED) {
 			return n->type = err(c, n->pos,
 			    "%s on non-tagged-union %s",
@@ -2049,7 +2076,7 @@ cexpr(Checker *c, Node *n)
 		}
 		if (n->kind == N_TRYPROP && has_errors) {
 			Type *r = c->ret;
-			Type *ru = (r && r->kind == TY_NAMED) ? r->under : r;
+			Type *ru = type_chase_named(r);
 			if (ru == NULL || ru->kind != TY_TAGGED) {
 				err(c, n->pos,
 				    "?: enclosing function must return a tagged "
@@ -2097,8 +2124,7 @@ cexpr(Checker *c, Node *n)
 			tp->type = cexpr(c, e);
 			Type *ed = type_default(tp->type);
 			if (ed && ed->align > al) al = ed->align;
-			Type *eu = (ed && ed->kind == TY_NAMED)
-			    ? ed->under : ed;
+			Type *eu = type_chase_named(ed);
 			if (eu && (eu->kind == TY_STR || eu->kind == TY_SLICE
 			    || eu->kind == TY_TAGGED))
 				sz += (eu->size + 7) & ~(u64)7;
@@ -2154,9 +2180,7 @@ clet(Checker *c, Node *n)
 	 * init) can't infer its length — that is a loud error, never a
 	 * silent zero-length array (rule 7, #7). */
 	if (declared && declared->kind == TY_ARRAY && declared->alen == 0) {
-		Type *iu = initt
-		    ? ((initt->kind == TY_NAMED) ? initt->under : initt)
-		    : NULL;
+		Type *iu = type_chase_named(initt);
 		if (iu && iu->kind == TY_ARRAY)
 			declared = type_array(c->a, declared->sub, iu->alen);
 		else
@@ -2195,8 +2219,7 @@ clet(Checker *c, Node *n)
 			}
 	}
 	if (has_arr_repeat && declared) {
-		Type *du = (declared->kind == TY_NAMED) ? declared->under
-		    : declared;
+		Type *du = type_chase_named(declared);
 		if (du && du->kind == TY_ARRAY)
 			has_arr_repeat = 0;
 	}
@@ -2303,7 +2326,11 @@ cstmt(Checker *c, Node *n)
 	}
 	case N_IF: {
 		Type *ct = cexpr(c, n->cond);
-		if (ct != ty_err && ct != ty_bool && ct != ty_untyped_bool)
+		/* harec dealiases at the if-cond consumer (ref/harec/src/
+		 * check.c:2141); ww accepts + runs alias-bool (F0 m2_if).
+		 * assert stays UN-chased — both stages loud there (F0 2a). */
+		Type *cu = type_chase_named(ct);
+		if (ct != ty_err && cu != ty_bool && cu != ty_untyped_bool)
 			err(c, n->pos, "if condition must be bool, got %s",
 			    type_name(c->a, ct));
 		cstmt(c, n->body);
@@ -2315,14 +2342,14 @@ cstmt(Checker *c, Node *n)
 		c->cur = newscope(c->a, saved);
 		c->loops++;
 		Type *st = cexpr(c, n->lhs);
-		Type *u = (st && st->kind == TY_NAMED) ? st->under : st;
+		Type *u = type_chase_named(st);
 		Type *elem = NULL;
 		if (u && (u->kind == TY_SLICE || u->kind == TY_ARRAY)) elem = u->sub;
 		else if (u && u->kind == TY_STR) elem = ty_u8;
 		else err(c, n->pos, "for-range needs slice/array/str");
 		if (n->list != NULL) {
 			/* tuple destructure: each name binds to a tuple field */
-			Type *etu = (elem && elem->kind == TY_NAMED) ? elem->under : elem;
+			Type *etu = type_chase_named(elem);
 			Tparam *tp = (etu && etu->kind == TY_TUPLE) ? etu->params : NULL;
 			for (Node *nm = n->list; nm; nm = nm->next) {
 				Type *ft = tp ? tp->type : ty_err;
@@ -2355,7 +2382,10 @@ cstmt(Checker *c, Node *n)
 		if (n->lhs) cstmt(c, n->lhs);	/* init may be a let or expr */
 		if (n->cond) {
 			Type *ct = cexpr(c, n->cond);
-			if (ct != ty_err && ct != ty_bool && ct != ty_untyped_bool)
+			/* harec dealiases at the loop-cond consumer (ref/
+			 * harec/src/check.c:2515); F0 m2_while. */
+			Type *cu = type_chase_named(ct);
+			if (ct != ty_err && cu != ty_bool && cu != ty_untyped_bool)
 				err(c, n->pos, "for condition must be bool, got %s",
 				    type_name(c->a, ct));
 		}
@@ -2855,9 +2885,7 @@ check_file(Checker *c, Node *file)
 				 * the right `.len`. */
 				if (d->type && d->type->kind == TY_ARRAY
 				    && d->type->alen == 0) {
-					Type *iu = rt
-					    ? ((rt->kind == TY_NAMED) ? rt->under : rt)
-					    : NULL;
+					Type *iu = type_chase_named(rt);
 					if (iu && iu->kind == TY_ARRAY) {
 						d->type = type_array(c->a,
 						    d->type->sub, iu->alen);
diff --git a/cmd/wcc/type.c b/cmd/wcc/type.c
index 3a449bae..570d5c54 100644
--- a/cmd/wcc/type.c
+++ b/cmd/wcc/type.c
@@ -147,6 +147,22 @@ type_named(Arena *a, const char *name, Type *under)
 	return t;
 }
 
+/* type_chase_named — walk the TY_NAMED.under chain to the deepest non-
+ * named type. Chain-of-aliases (#22): `type b = a; type a = struct;`
+ * stacks two TY_NAMED layers — a single peel leaves `t` pointing at
+ * the inner alias (still TY_NAMED), so kind-gated arms (TY_STRUCT,
+ * TY_SLICE, TY_TAGGED, TY_PTR) miss and the consumer silently falls
+ * through to a scalar shape. Mirror of wwstage's structlookupchain /
+ * resolvealias and harec's type_dealias (ref/harec/src/types.c:53).
+ * Promoted from cmd/w6c/cgen.c for the #5 alias arc so the checker's
+ * acceptance sites and the cgen classify sites share one peel. */
+Type *
+type_chase_named(Type *t)
+{
+	while (t && t->kind == TY_NAMED) t = t->under;
+	return t;
+}
+
 int
 type_isint(Type *t)
 {
@@ -297,11 +313,11 @@ type_assignable(Type *dst, Type *src)
 	 *     src appears as a variant of dst (Hare-style subset). Tag
 	 *     remap at the use site handles different variant indices.
 	 * Checked before the untyped branch so untyped literals flow
-	 * through to a variant's typed slot. Unwraps a NAMED alias on
-	 * either side so `type result = (T|E);` accepts variants too. */
+	 * through to a variant's typed slot. Chases the NAMED alias chain
+	 * on either side so `type result = (T|E);` accepts variants too. */
 	{
-		Type *du = (dst->kind == TY_NAMED) ? dst->under : dst;
-		Type *su = (src->kind == TY_NAMED) ? src->under : src;
+		Type *du = type_chase_named(dst);
+		Type *su = type_chase_named(src);
 		if (du && du->kind == TY_TAGGED &&
 		    !(su && su->kind == TY_TAGGED)) {
 			/* #199(α): direct variant only — no transitive drill into
@@ -314,8 +330,7 @@ type_assignable(Type *dst, Type *src)
 			 * `is`/`as`'s non-recursive variant lookup. Callers compose
 			 * `let inner: Wrapper = sub; let r: parent = inner;`. */
 			for (Tparam *p = du->params; p; p = p->next) {
-				Type *pu = (p->type && p->type->kind == TY_NAMED)
-				    ? p->type->under : p->type;
+				Type *pu = type_chase_named(p->type);
 				if (pu && pu->kind == TY_TAGGED) {
 					if (type_eq(p->type, src)) return 1;
 					continue;
@@ -335,8 +350,7 @@ type_assignable(Type *dst, Type *src)
 			 * the subset loop below would reject. SSoT with `is`/`as`
 			 * variant lookup (#198 family). */
 			for (Tparam *dp = du->params; dp; dp = dp->next) {
-				Type *pu = (dp->type && dp->type->kind == TY_NAMED)
-				    ? dp->type->under : dp->type;
+				Type *pu = type_chase_named(dp->type);
 				if (pu && pu->kind == TY_TAGGED &&
 				    type_eq(dp->type, src)) return 1;
 			}
@@ -354,15 +368,15 @@ type_assignable(Type *dst, Type *src)
 
 	/* Untyped → typed: only if the typed kind can hold the value. */
 	if (type_isuntyped(src)) {
+		Type *du = type_chase_named(dst);
 		if (src->kind == TY_UNTYPED_INT && type_isnum(dst)) return 1;
 		if (src->kind == TY_UNTYPED_FLOAT && type_isfloat(dst)) return 1;
-		if (src->kind == TY_UNTYPED_STR && (dst->kind == TY_STR ||
-		    (dst->kind == TY_NAMED && dst->under && dst->under->kind == TY_STR))) return 1;
+		if (src->kind == TY_UNTYPED_STR && du && du->kind == TY_STR)
+			return 1;
 		if (src->kind == TY_UNTYPED_RUNE && (type_isint(dst) || dst->kind == TY_RUNE)) return 1;
-		if (src->kind == TY_UNTYPED_BOOL && (dst->kind == TY_BOOL ||
-		    (dst->kind == TY_NAMED && dst->under && dst->under->kind == TY_BOOL))) return 1;
+		if (src->kind == TY_UNTYPED_BOOL && du && du->kind == TY_BOOL)
+			return 1;
 		if (src->kind == TY_UNTYPED_NIL) {
-			Type *du = (dst->kind == TY_NAMED) ? dst->under : dst;
 			if (du && (du->kind == TY_PTR || du->kind == TY_SLICE ||
 			    du->kind == TY_CHAN || du->kind == TY_FN))
 				return 1;
@@ -370,11 +384,16 @@ type_assignable(Type *dst, Type *src)
 		return 0;
 	}
 
-	/* Named on either side: compare to the underlying. NAMED is a
-	 * distinct type from its under; but assignment from under to
-	 * named (and vice-versa) is allowed in this minimal checker. */
-	if (dst->kind == TY_NAMED && type_eq(dst->under, src)) return 1;
-	if (src->kind == TY_NAMED && type_eq(dst, src->under)) return 1;
+	/* Named on either side: assignable through the FULL alias chain.
+	 * harec type_is_assignable dealiases both sides whenever the dst
+	 * is not tagged (ref/harec/src/types.c:993-996; the tagged dst
+	 * returned above) — so base↔alias and alias↔alias-of-same-base
+	 * all flow. The pre-#5 single peel rejected any 2-level chain
+	 * (`return x*2` from a myint2 local louded at the int return). */
+	if (dst->kind == TY_NAMED || src->kind == TY_NAMED) {
+		if (type_eq(type_chase_named(dst), type_chase_named(src)))
+			return 1;
+	}
 
 	/* Tuple-to-tuple: element-wise assignable. */
 	if (dst->kind == TY_TUPLE && src->kind == TY_TUPLE) {
@@ -397,8 +416,8 @@ type_assignable(Type *dst, Type *src)
 	 * {.ptr=&arr[0], .len=N, .cap=N} is byte-identical across stages.
 	 * Element types must match exactly — no element decay. */
 	{
-		Type *du = (dst->kind == TY_NAMED) ? dst->under : dst;
-		Type *su = (src->kind == TY_NAMED) ? src->under : src;
+		Type *du = type_chase_named(dst);
+		Type *su = type_chase_named(src);
 		if (du && su && du->kind == TY_SLICE && su->kind == TY_ARRAY &&
 		    su->alen != SIZE_UNDEFINED && type_eq(du->sub, su->sub))
 			return 1;
@@ -421,8 +440,8 @@ type_assignable(Type *dst, Type *src)
 	 * Both rules fire only when the destination element is opaque, so
 	 * they are inert on the opaque-free selfhost corpus. */
 	{
-		Type *du = (dst->kind == TY_NAMED) ? dst->under : dst;
-		Type *su = (src->kind == TY_NAMED) ? src->under : src;
+		Type *du = type_chase_named(dst);
+		Type *su = type_chase_named(src);
 		if (du && su && du->kind == su->kind &&
 		    (du->kind == TY_PTR || du->kind == TY_SLICE) &&
 		    du->sub && du->sub->kind == TY_OPAQUE)
diff --git a/cmd/wcc/ww.h b/cmd/wcc/ww.h
index cd2d3886..3928885e 100644
--- a/cmd/wcc/ww.h
+++ b/cmd/wcc/ww.h
@@ -472,6 +472,7 @@ Type	*type_chan(Arena*, Type *sub);
 Type	*type_named(Arena*, const char *name, Type *under);
 const char *type_name(Arena*, Type*);	/* arena'd debug string */
 int	type_eq(Type *a, Type *b);		/* structural equality */
+Type	*type_chase_named(Type *t);		/* transitive TY_NAMED peel */
 int	type_isint(Type *t);
 int	type_isfloat(Type *t);
 int	type_isnum(Type *t);
diff --git a/test/wcc/944_alias_accept_run.c b/test/wcc/944_alias_accept_run.c
new file mode 100644
index 00000000..91d0b41f
--- /dev/null
+++ b/test/wcc/944_alias_accept_run.c
@@ -0,0 +1,711 @@
+/*
+ * 944_alias_accept_run — #5 alias arc F1: cstage acceptance ALIGN-UP
+ * through the transitive TY_NAMED chase (type_chase_named, promoted to
+ * cmd/wcc/type.c). harec dealiases at every promotion/cond/assign
+ * consumer (ref/harec/src/types.c:53 type_dealias; :989-996
+ * type_is_assignable; src/check.c:1083-1105 type_promote; :2141 if,
+ * :2515 for, :3229 &&/||, :3572 !) — wwstage already accepted these
+ * shapes AND ran them Hare-right (F0 census /tmp/f0/livelist.md), so
+ * the cstage single-peel rejects were the lean side aligned UP.
+ *
+ *   row                  | shape                                | want
+ *   ---------------------+--------------------------------------+-----
+ *   binop_alias_base     | myint + int (F0 m1_binop)            | 0
+ *   binop_2level         | myint2 % int, myu / u32 (m1_binop2)  | 0
+ *   ret_through_2level   | fn(x: myint2) int = x * 2            | 0
+ *   assign_alias_alias   | k1 → k2 (same base; harec dealias-   |
+ *                        | both admits)                         | 0
+ *   binop_alias_vs_alias | k1 + k2 — cstage stays LOUD per      |
+ *                        | harec type_promote ALIAS+ALIAS→NULL  | err(cs)
+ *   cond_if/for/bang/    | alias-of-bool at every cond consumer |
+ *   andor/fnparam        | (F0 m2_* family)                     | 0
+ *   assert_stays_loud    | alias-bool assert — BOTH stages loud |
+ *                        | (F0 2a DISSOLVED-SYMMETRIC; the Hare |
+ *                        | widening is parked on #5)            | err
+ *   dot_2level           | field access via a3=b3=c3=struct     |
+ *                        | (task #70, ken c3_chain3)            | 0
+ *   deref_alias_ptr      | *p through pi2=pi=*int               | 0
+ *   idx/slice/range_     | index/slice/for-range over 2-level   |
+ *   2level, slice_arg    | alias bases (F0 8b) — cs cgen index  |
+ *                        | family chased (idx_eff + base        |
+ *                        | classify); CS-ONLY rows: the wwstage |
+ *                        | half is the task-#60 esz family (F2  |
+ *                        | batch 1) — flip to K_RUN when it     |
+ *                        | lands                                | 0(cs)
+ *   float_alias_param* / | ken-v3 leg: 2-level f64/str/slice    |
+ *   str_alias_2level /   | aliases at the cgen KIND classifiers |
+ *   slice_alias_param    | (slice leg cs-only, #60)             | 0
+ *   slicefield_* /       | reviewer-F1 leg: 2-level alias of    |
+ *   strfield_store_2lvl  | slice/str as a STRUCT FIELD type —   |
+ *                        | cgen field gates chased (stores,     |
+ *                        | struct-lit, walk leaves, reads);     |
+ *                        | unprobed gates LOUD-tripwired (#73,  |
+ *                        | K_BUILDERR_CS pin)                   | 0
+ *
+ * K_RUN rows also assert cstage/wwstage asm byte-id (acceptance
+ * graduations land byte-identical — F0's accept side was wwstage).
+ * K_RUN_CS / K_BUILDERR_CS rows run the cstage driver only, each
+ * citing the task that graduates them. binop_alias_vs_alias is
+ * CS-only loud: the wwstage checker stays silent on typed mismatches
+ * by design (5-lite discipline) — cs pins the harec-parity reject.
+ * NNN<950, self-contained (/tmp, no imports) — rule-14's selfhost-
+ * sibling race does not apply (941/944 precedent).
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/stat.h>
+#include <sys/wait.h>
+
+static int
+runwait(const char *cmd)
+{
+	int rc = system(cmd);
+	if (rc == -1) return -1;
+	if (WIFEXITED(rc)) return WEXITSTATUS(rc);
+	return -1;
+}
+
+static int
+slurp_eq(const char *a, const char *b)
+{
+	FILE *fa = fopen(a, "rb");
+	FILE *fb = fopen(b, "rb");
+	if (!fa || !fb) { if (fa) fclose(fa); if (fb) fclose(fb); return -1; }
+	int rc = 0;
+	for (;;) {
+		int ca = fgetc(fa), cb = fgetc(fb);
+		if (ca != cb) { rc = -1; break; }
+		if (ca == EOF) break;
+	}
+	fclose(fa); fclose(fb);
+	return rc;
+}
+
+#define K_RUN          0	/* build+run BOTH drivers, exit==want, + byte-id */
+#define K_BUILDERR     1	/* build FAILS with experr on BOTH drivers */
+#define K_RUN_CS       2	/* cstage only — ww half pending (cite at row) */
+#define K_BUILDERR_CS  3	/* cstage-only loud (ww silent by design) */
+
+struct row { const char *label; const char *src; int want;
+             int kind; const char *experr; };
+
+/* errlog_has — a BUILDERR row must fail WITH its diagnostic; any other
+ * failure (parse error, crash, hang-kill) is a vacuous reject (940
+ * precedent). */
+static int
+errlog_has(const char *path, const char *needle)
+{
+	FILE *f = fopen(path, "rb");
+	if (!f) return 0;
+	char buf[8192];
+	size_t got = fread(buf, 1, sizeof buf - 1, f);
+	fclose(f);
+	buf[got] = '\0';
+	return strstr(buf, needle) != NULL;
+}
+
+static const struct row rows[] = {
+	{ "binop_alias_base",
+	  "package main;\n"
+	  "type myint = int;\n"
+	  "export fn main() i32 = {\n"
+	  "	let a: myint = 5;\n"
+	  "	let b: int = 3;\n"
+	  "	let c = a + b;\n"
+	  "	if (c != 8) { return 1; };\n"
+	  "	let d: myint = 2;\n"
+	  "	if (a * d != 10) { return 2; };\n"
+	  "	if (a < b) { return 3; };\n"
+	  "	if (a - b != 2) { return 4; };\n"
+	  "	return 0;\n"
+	  "};\n", 0, K_RUN, NULL },
+	{ "binop_2level",
+	  "package main;\n"
+	  "type myint = int;\n"
+	  "type myint2 = myint;\n"
+	  "type myu = u32;\n"
+	  "export fn main() i32 = {\n"
+	  "	let a: myint2 = 7;\n"
+	  "	let b: int = 2;\n"
+	  "	if (a % b != 1) { return 1; };\n"
+	  "	let u: myu = 10: u32;\n"
+	  "	let v: u32 = 3: u32;\n"
+	  "	if (u / v != 3: u32) { return 2; };\n"
+	  "	if (u + v != 13: u32) { return 3; };\n"
+	  "	return 0;\n"
+	  "};\n", 0, K_RUN, NULL },
+	{ "ret_through_2level",
+	  "package main;\n"
+	  "type myint = int;\n"
+	  "type myint2 = myint;\n"
+	  "fn dbl(x: myint2) int = {\n"
+	  "	return x * 2;\n"
+	  "};\n"
+	  "export fn main() i32 = {\n"
+	  "	let a: myint2 = 21;\n"
+	  "	if (dbl(a) != 42) { return 1; };\n"
+	  "	return 0;\n"
+	  "};\n", 0, K_RUN, NULL },
+	{ "assign_alias_alias",
+	  "package main;\n"
+	  "type k1 = int;\n"
+	  "type k2 = int;\n"
+	  "export fn main() i32 = {\n"
+	  "	let x: k1 = 5;\n"
+	  "	let y: k2 = x;\n"
+	  "	if (y != 5) { return 1; };\n"
+	  "	return 0;\n"
+	  "};\n", 0, K_RUN, NULL },
+	/* harec type_promote: ALIAS+ALIAS → NULL even on a shared base
+	 * (ref/harec/src/check.c:1087-1089). wwstage's checker is silent
+	 * on typed mismatches (5-lite) — cs-only pin. */
+	{ "binop_alias_vs_alias",
+	  "package main;\n"
+	  "type k1 = int;\n"
+	  "type k2 = int;\n"
+	  "export fn main() i32 = {\n"
+	  "	let x: k1 = 5;\n"
+	  "	let y: k2 = 3;\n"
+	  "	if (x + y != 8) { return 1; };\n"
+	  "	return 0;\n"
+	  "};\n", 0, K_BUILDERR_CS, "operands have differing types" },
+	{ "cond_if",
+	  "package main;\n"
+	  "type myb = bool;\n"
+	  "export fn main() i32 = {\n"
+	  "	let b: myb = true;\n"
+	  "	if (b) { return 0; };\n"
+	  "	return 1;\n"
+	  "};\n", 0, K_RUN, NULL },
+	{ "cond_for",
+	  "package main;\n"
+	  "type myb = bool;\n"
+	  "export fn main() i32 = {\n"
+	  "	let b: myb = true;\n"
+	  "	let i: int = 0;\n"
+	  "	for (b) {\n"
+	  "		i = i + 1;\n"
+	  "		if (i >= 3) { b = false; };\n"
+	  "	};\n"
+	  "	if (i != 3) { return 1; };\n"
+	  "	return 0;\n"
+	  "};\n", 0, K_RUN, NULL },
+	{ "cond_bang",
+	  "package main;\n"
+	  "type myb = bool;\n"
+	  "export fn main() i32 = {\n"
+	  "	let b: myb = false;\n"
+	  "	let n = !b;\n"
+	  "	if (!n) { return 1; };\n"
+	  "	return 0;\n"
+	  "};\n", 0, K_RUN, NULL },
+	{ "cond_andor",
+	  "package main;\n"
+	  "type myb = bool;\n"
+	  "export fn main() i32 = {\n"
+	  "	let b: myb = true;\n"
+	  "	let c: myb = false;\n"
+	  "	if (b && !c) { } else { return 1; };\n"
+	  "	if (c || b) { } else { return 2; };\n"
+	  "	return 0;\n"
+	  "};\n", 0, K_RUN, NULL },
+	{ "cond_fnparam",
+	  "package main;\n"
+	  "type myb = bool;\n"
+	  "fn pick(b: myb) i32 = {\n"
+	  "	if (b) { return 0; };\n"
+	  "	return 1;\n"
+	  "};\n"
+	  "export fn main() i32 = {\n"
+	  "	let b: myb = true;\n"
+	  "	return pick(b);\n"
+	  "};\n", 0, K_RUN, NULL },
+	{ "assert_stays_loud",
+	  "package main;\n"
+	  "type myb = bool;\n"
+	  "export fn main() i32 = {\n"
+	  "	let b: myb = true;\n"
+	  "	assert(b);\n"
+	  "	return 0;\n"
+	  "};\n", 0, K_BUILDERR, "assert: cond must be bool" },
+	{ "dot_2level",
+	  "package main;\n"
+	  "type a3 = b3;\n"
+	  "type b3 = c3;\n"
+	  "type c3 = struct { x: size, y: size, z: size };\n"
+	  "export fn main() i32 = {\n"
+	  "	if (size(a3) != 24) { return 1; };\n"
+	  "	if (size((void | a3)) != 32) { return 2; };\n"
+	  "	let v: a3;\n"
+	  "	v.x = 1; v.y = 2; v.z = 3;\n"
+	  "	if (v.x + v.y + v.z != 6) { return 3; };\n"
+	  "	return 0;\n"
+	  "};\n", 0, K_RUN, NULL },
+	{ "deref_alias_ptr",
+	  "package main;\n"
+	  "type pi = *int;\n"
+	  "type pi2 = pi;\n"
+	  "export fn main() i32 = {\n"
+	  "	let v: int = 41;\n"
+	  "	let p: pi2 = &v;\n"
+	  "	if (*p != 41) { return 1; };\n"
+	  "	*p = 7;\n"
+	  "	if (v != 7) { return 2; };\n"
+	  "	return 0;\n"
+	  "};\n", 0, K_RUN, NULL },
+	/* ---- reviewer-F1 find: 2-level alias of slice/str as a STRUCT
+	 * FIELD type. The acceptance above admits every construction; the
+	 * cgen FIELD-TYPE gates single-peeled, so the slice/str 3-word
+	 * arms fell to word0-only scalar tails — SILENT wrong (ww correct,
+	 * every shape LOUD at pristine 738d7f4 = opened by this commit).
+	 * Chased gates: single-dot store (+via-ptr), struct-lit fill,
+	 * chained store-walk leaf, chained-ptr-field store, single-dot /
+	 * via-ptr / chained-walk reads. Each row pins one gate; the
+	 * noise() call clobbers BX/CX so stale-register luck can't pass a
+	 * word0-only header. Unprobed sibling gates are LOUD-tripwired,
+	 * pinned by the #73 row at the end of this block. Rows whose
+	 * `.len` readback rides the chained-dot READ walk are K_RUN_CS
+	 * here (runtime-correct both stages; cs takes the generic spine
+	 * pre-#71) and flip to K_RUN at the #71 walk-chase commit, which
+	 * graduates their byte-id. */
+	{ "slicefield_store_2lvl",
+	  "package main;\n"
+	  "type sl = []int;\n"
+	  "type sl2 = sl;\n"
+	  "type box = struct { s: sl2, n: int };\n"
+	  "export fn main() i32 = {\n"
+	  "	let a: [3]int = [700: int, 800: int, 900: int];\n"
+	  "	let b: box;\n"
+	  "	b.n = 5;\n"
+	  "	b.s = a[0:3];\n"
+	  "	if (b.n != 5) { return 9; };\n"
+	  "	if (b.s[0] != 700) { return 1; };\n"
+	  "	if (b.s[2] != 900) { return 2; };\n"
+	  "	if (b.s.len != 3) { return 3; };\n"
+	  "	return 0;\n"
+	  "};\n", 0, K_RUN_CS, NULL },	/* ->K_RUN at the #71 walk-chase commit */
+	{ "slicefield_range_2lvl",
+	  "package main;\n"
+	  "type sl = []int;\n"
+	  "type sl2 = sl;\n"
+	  "type box = struct { s: sl2, n: int };\n"
+	  "export fn main() i32 = {\n"
+	  "	let a: [3]int = [700: int, 800: int, 900: int];\n"
+	  "	let b: box;\n"
+	  "	b.s = a[0:3];\n"
+	  "	b.n = 5;\n"
+	  "	if (b.s.len != 3) { return 1; };\n"
+	  "	if (b.s[2] != 900) { return 2; };\n"
+	  "	for (let x .. b.s) {\n"
+	  "		if (x < 700) { return 3; };\n"
+	  "	};\n"
+	  "	return 0;\n"
+	  "};\n", 0, K_RUN_CS, NULL },	/* ->K_RUN at the #71 walk-chase commit */
+	{ "strfield_store_2lvl",
+	  "package main;\n"
+	  "type s1t = str;\n"
+	  "type s2t = s1t;\n"
+	  "type box = struct { s: s2t, n: int };\n"
+	  "export fn main() i32 = {\n"
+	  "	let b: box;\n"
+	  "	b.s = \"hello\";\n"
+	  "	b.n = 5;\n"
+	  "	if (b.s.len != 5) { return 1; };\n"
+	  "	return 0;\n"
+	  "};\n", 0, K_RUN_CS, NULL },	/* ->K_RUN at the #71 walk-chase commit */
+	{ "slicefield_structlit_2lvl",
+	  "package main;\n"
+	  "type sl = []int;\n"
+	  "type sl2 = sl;\n"
+	  "type box = struct { s: sl2, n: int };\n"
+	  "export fn main() i32 = {\n"
+	  "	let a: [3]int = [700: int, 800: int, 900: int];\n"
+	  "	let b: box = box { s = a[0:3], n = 5: int };\n"
+	  "	if (b.n != 5) { return 1; };\n"
+	  "	if (b.s.len != 3) { return 2; };\n"
+	  "	if (b.s[2] != 900) { return 3; };\n"
+	  "	return 0;\n"
+	  "};\n", 0, K_RUN_CS, NULL },	/* ->K_RUN at the #71 walk-chase commit */
+	{ "slicefield_viaptr_2lvl",
+	  "package main;\n"
+	  "type sl = []int;\n"
+	  "type sl2 = sl;\n"
+	  "type box = struct { s: sl2, n: int };\n"
+	  "export fn main() i32 = {\n"
+	  "	let a: [3]int = [700: int, 800: int, 900: int];\n"
+	  "	let b: box;\n"
+	  "	let p = &b;\n"
+	  "	p.s = a[0:3];\n"
+	  "	if (p.s.len != 3) { return 1; };\n"
+	  "	if (p.s[2] != 900) { return 2; };\n"
+	  "	return 0;\n"
+	  "};\n", 0, K_RUN_CS, NULL },	/* ->K_RUN at the #71 walk-chase commit */
+	{ "slicefield_chainstore_2lvl",
+	  "package main;\n"
+	  "type sl = []int;\n"
+	  "type sl2 = sl;\n"
+	  "type inner = struct { s: sl2 };\n"
+	  "type outer = struct { i: inner };\n"
+	  "export fn main() i32 = {\n"
+	  "	let a: [3]int = [700: int, 800: int, 900: int];\n"
+	  "	let v: outer;\n"
+	  "	v.i.s = a[0:3];\n"
+	  "	if (v.i.s.len != 3) { return 1; };\n"
+	  "	if (v.i.s[2] != 900) { return 2; };\n"
+	  "	return 0;\n"
+	  "};\n", 0, K_RUN_CS, NULL },	/* ->K_RUN at the #71 walk-chase commit */
+	{ "slicefield_ptrchain_2lvl",
+	  "package main;\n"
+	  "type sl = []int;\n"
+	  "type sl2 = sl;\n"
+	  "type inner = struct { s: sl2, n: int };\n"
+	  "type outer = struct { pi: *inner };\n"
+	  "export fn main() i32 = {\n"
+	  "	let a: [3]int = [700: int, 800: int, 900: int];\n"
+	  "	let i: inner;\n"
+	  "	i.n = 1;\n"
+	  "	let v: outer;\n"
+	  "	v.pi = &i;\n"
+	  "	v.pi.s = a[0:3];\n"
+	  "	if (i.s.len != 3) { return 1; };\n"
+	  "	if (i.s[2] != 900) { return 2; };\n"
+	  "	return 0;\n"
+	  "};\n", 0, K_RUN_CS, NULL },	/* ->K_RUN at the #71 walk-chase commit */
+	{ "slicefield_chainread_2lvl",
+	  "package main;\n"
+	  "type sl = []int;\n"
+	  "type sl2 = sl;\n"
+	  "type inner = struct { s: sl2 };\n"
+	  "type outer = struct { i: inner };\n"
+	  "fn noise(x: int) int = {\n"
+	  "	return x * 7 + 3;\n"
+	  "};\n"
+	  "export fn main() i32 = {\n"
+	  "	let a: [3]int = [700: int, 800: int, 900: int];\n"
+	  "	let v: outer;\n"
+	  "	v.i.s = a[0:3];\n"
+	  "	let k = noise(9);\n"
+	  "	if (k != 66) { return 9; };\n"
+	  "	let w = v.i.s;\n"
+	  "	if (w.len != 3) { return 1; };\n"
+	  "	return 0;\n"
+	  "};\n", 0, K_RUN, NULL },
+	{ "slicefield_ptrread_2lvl",
+	  "package main;\n"
+	  "type sl = []int;\n"
+	  "type sl2 = sl;\n"
+	  "type box = struct { s: sl2, n: int };\n"
+	  "fn noise(x: int) int = {\n"
+	  "	return x * 7 + 3;\n"
+	  "};\n"
+	  "export fn main() i32 = {\n"
+	  "	let a: [3]int = [700: int, 800: int, 900: int];\n"
+	  "	let b: box;\n"
+	  "	b.s = a[0:3];\n"
+	  "	let p = &b;\n"
+	  "	let k = noise(9);\n"
+	  "	if (k != 66) { return 9; };\n"
+	  "	let w = p.s;\n"
+	  "	if (w.len != 3) { return 1; };\n"
+	  "	return 0;\n"
+	  "};\n", 0, K_RUN, NULL },
+	/* whole-field read into a local: cs runtime-correct post-chase
+	 * (the clobbered-register r1b probe), but the `let w = b.s`
+	 * receive spine diverges cs vs ww at ONE level already (byte-id
+	 * NO at pristine 738d7f4 = pre-existing, #71-style divergence,
+	 * filed under #73's census) and ww's `w[i]` read is the task-#60
+	 * esz family — cs-only until both land. */
+	{ "slicefield_wholeread_2lvl",
+	  "package main;\n"
+	  "type sl = []int;\n"
+	  "type sl2 = sl;\n"
+	  "type box = struct { s: sl2, n: int };\n"
+	  "fn noise(x: int) int = {\n"
+	  "	return x * 7 + 3;\n"
+	  "};\n"
+	  "export fn main() i32 = {\n"
+	  "	let a: [3]int = [700: int, 800: int, 900: int];\n"
+	  "	let b: box;\n"
+	  "	b.s = a[0:3];\n"
+	  "	let k = noise(9);\n"
+	  "	if (k != 66) { return 9; };\n"
+	  "	let w = b.s;\n"
+	  "	if (w.len != 3) { return 1; };\n"
+	  "	if (w[2] != 900) { return 2; };\n"
+	  "	return 0;\n"
+	  "};\n", 0, K_RUN_CS, NULL },	/* ww: task #60 (F2 batch 1) */
+	/* #73 tripwire pin: the UNPROBED single-peel field gates
+	 * (indexed-elem store/read, ptr-chain read, heap fill, tuple-elem
+	 * read, static emit) hard-error on a 2+-level alias over an
+	 * aggregate base instead of emitting a word0 tail. ww accepts and
+	 * runs these — cs-only loud until #73's chase. 1-level controls
+	 * verified per gate (/tmp/revF1 t*c probes). */
+	{ "slicefield_idx_tripwire_73",
+	  "package main;\n"
+	  "type sl = []int;\n"
+	  "type sl2 = sl;\n"
+	  "type box = struct { s: sl2, n: int };\n"
+	  "export fn main() i32 = {\n"
+	  "	let a: [3]int = [700: int, 800: int, 900: int];\n"
+	  "	let xs: [2]box;\n"
+	  "	xs[0].s = a[0:3];\n"
+	  "	if (xs[0].s.len != 3) { return 1; };\n"
+	  "	return 0;\n"
+	  "};\n", 0, K_BUILDERR_CS,
+	  "unswept single-peel gate (#73)" },
+	/* Values >255 break the esz=1 prefix-luck; the write-then-read
+	 * pins the IMULQ stride on both the read and write spines. */
+	{ "idx_2level",
+	  "package main;\n"
+	  "type arr = [4]int;\n"
+	  "type arr2 = arr;\n"
+	  "export fn main() i32 = {\n"
+	  "	let a: arr2 = [1000: int, 2000: int, 3000: int, 4000: int];\n"
+	  "	if (a[2] != 3000) { return 1; };\n"
+	  "	a[1] = 9999;\n"
+	  "	if (a[1] != 9999) { return 2; };\n"
+	  "	return 0;\n"
+	  "};\n", 0, K_RUN_CS, NULL },	/* ww: task #60 (F2 batch 1) */
+	{ "slice_2level",
+	  "package main;\n"
+	  "type sl = []int;\n"
+	  "type sl2 = sl;\n"
+	  "export fn main() i32 = {\n"
+	  "	let a: [4]int = [1000: int, 2000: int, 3000: int, 4000: int];\n"
+	  "	let s: sl2 = a[1:3];\n"
+	  "	if (s.len != 2) { return 1; };\n"
+	  "	if (s[0] != 2000) { return 2; };\n"
+	  "	s[1] = 7777;\n"
+	  "	if (a[2] != 7777) { return 3; };\n"
+	  "	return 0;\n"
+	  "};\n", 0, K_RUN_CS, NULL },	/* ww: task #60 (F2 batch 1) */
+	{ "range_2level",
+	  "package main;\n"
+	  "type arr = [4]int;\n"
+	  "type arr2 = arr;\n"
+	  "export fn main() i32 = {\n"
+	  "	let a: arr2 = [1: int, 2: int, 3: int, 4: int];\n"
+	  "	let sum: int = 0;\n"
+	  "	for (let x .. a) {\n"
+	  "		sum = sum + x;\n"
+	  "	};\n"
+	  "	if (sum != 10) { return 1; };\n"
+	  "	return 0;\n"
+	  "};\n", 0, K_RUN_CS, NULL },	/* ww: task #60 (F2 batch 1) */
+	{ "slice_of_alias_arg",
+	  "package main;\n"
+	  "type arr = [4]int;\n"
+	  "type arr2 = arr;\n"
+	  "fn sum(s: []int) int = {\n"
+	  "	let t: int = 0;\n"
+	  "	for (let x .. s) { t = t + x; };\n"
+	  "	return t;\n"
+	  "};\n"
+	  "export fn main() i32 = {\n"
+	  "	let a: arr2 = [1000: int, 2000: int, 3000: int, 4000: int];\n"
+	  "	let s = a[1:3];\n"
+	  "	if (s.len != 2) { return 1; };\n"
+	  "	if (s[1] != 3000) { return 2; };\n"
+	  "	if (sum(a[0:4]) != 10000) { return 3; };\n"
+	  "	return 0;\n"
+	  "};\n", 0, K_RUN_CS, NULL },	/* ww: task #60 (F2 batch 1) */
+	/* ---- ken-v3 leg: the acceptance align above opens 2-level
+	 * float/str/slice aliases to the cgen KIND classifiers
+	 * (cg_isfloat/type_isf32/fld_isfloat/type_isstr/type_isslice),
+	 * whose single peel classed them scalar/INT — the f64-alias param
+	 * would read the wrong register class (cs exit 1 SILENT, ww
+	 * correct). The classifiers chase IN THIS SAME COMMIT so the
+	 * widening never ships a loud->silent flip (rule 7; ken root-
+	 * verify /tmp/ken_f1, his v3 row below). */
+	{ "float_alias_param_kenv3",
+	  "package main;\n"
+	  "type fa = fb;\n"
+	  "type fb = f64;\n"
+	  "fn take(x: fa) f64 = {\n"
+	  "	return x * 2.0;\n"
+	  "};\n"
+	  "export fn main() i32 = {\n"
+	  "	if (take(1.5) != 3.0) { return 1; };\n"
+	  "	return 0;\n"
+	  "};\n", 0, K_RUN, NULL },
+	{ "float_alias_param",
+	  "package main;\n"
+	  "type f1t = f64;\n"
+	  "type f2t = f1t;\n"
+	  "fn half(x: f2t) f64 = {\n"
+	  "	return x / 2.0;\n"
+	  "};\n"
+	  "export fn main() i32 = {\n"
+	  "	let v: f2t = 5.0;\n"
+	  "	if (half(v) != 2.5) { return 1; };\n"
+	  "	return 0;\n"
+	  "};\n", 0, K_RUN, NULL },
+	{ "str_alias_2level",
+	  "package main;\n"
+	  "type s1t = str;\n"
+	  "type s2t = s1t;\n"
+	  "fn taillen(s: s2t) int = {\n"
+	  "	return (s.len: int);\n"
+	  "};\n"
+	  "export fn main() i32 = {\n"
+	  "	let v: s2t = \"hello\";\n"
+	  "	if (v.len != 5) { return 1; };\n"
+	  "	if (taillen(v) != 5) { return 2; };\n"
+	  "	let w: s2t = v;\n"
+	  "	if (w.len != 5) { return 3; };\n"
+	  "	return 0;\n"
+	  "};\n", 0, K_RUN, NULL },
+	/* slice leg: cs classify fixed; the ww half of the indexed read
+	 * is the task-#60 esz family — cs-only until F2. Values >255
+	 * break the esz=1 prefix-luck. */
+	{ "slice_alias_param",
+	  "package main;\n"
+	  "type b1 = []int;\n"
+	  "type b2 = b1;\n"
+	  "fn first(s: b2) int = {\n"
+	  "	return s[0];\n"
+	  "};\n"
+	  "export fn main() i32 = {\n"
+	  "	let a: [3]int = [1000: int, 2000: int, 3000: int];\n"
+	  "	let s: b2 = a[0:3];\n"
+	  "	if (first(s) != 1000) { return 1; };\n"
+	  "	return 0;\n"
+	  "};\n", 0, K_RUN_CS, NULL },	/* ww: task #60 (F2 batch 1) */
+};
+
+static int
+run_driver(const char *driver, const struct row *r, int i)
+{
+	char src[96], tmpdir[96], errf[96], cmd[1024];
+	snprintf(src, sizeof src, "/tmp/aac_%d_%d.ww", getpid(), i);
+	snprintf(tmpdir, sizeof tmpdir, "/tmp/aac_%d_d_%d", getpid(), i);
+	snprintf(errf, sizeof errf, "/tmp/aac_%d_e_%d", getpid(), i);
+
+	FILE *f = fopen(src, "wb");
+	if (!f) return -1;
+	fputs(r->src, f);
+	fclose(f);
+
+	mkdir(tmpdir, 0755);
+	snprintf(cmd, sizeof cmd,
+	    "cd %s && timeout 20 %s build %s >/dev/null 2>%s",
+	    tmpdir, driver, src, errf);
+	int brc = runwait(cmd);
+	if (r->kind == K_BUILDERR || r->kind == K_BUILDERR_CS) {
+		int ok = (brc != 0)
+		    && (r->experr == NULL || errlog_has(errf, r->experr));
+		if (!ok)
+			fprintf(stderr, "row[%s]: %s expected loud builderr "
+			    "\"%s\" (brc=%d)\n", r->label, driver,
+			    r->experr ? r->experr : "", brc);
+		unlink(src); unlink(errf); rmdir(tmpdir);
+		return ok ? 0 : 1;
+	}
+	if (brc != 0) {
+		fprintf(stderr, "row[%s]: build via %s failed\n",
+		    r->label, driver);
+		unlink(src); unlink(errf); rmdir(tmpdir);
+		return -1;
+	}
+
+	const char *base = strrchr(src, '/');
+	base = base ? base + 1 : src;
+	char outbin[256];
+	snprintf(outbin, sizeof outbin, "%s/%s", tmpdir, base);
+	char *dot = strrchr(outbin, '.');
+	if (dot && strcmp(dot, ".ww") == 0) *dot = '\0';
+	int got = runwait(outbin);
+
+	unlink(src); unlink(outbin); unlink(errf); rmdir(tmpdir);
+	if (got != r->want) {
+		fprintf(stderr, "row[%s]: %s exit %d, want %d\n",
+		    r->label, driver, got, r->want);
+		return 1;
+	}
+	return 0;
+}
+
+static int
+asm_byte_identical(const char *bin, const struct row *r, int i)
+{
+	char src[96], cs[96], ws[96], cmd[1024];
+	snprintf(src, sizeof src, "/tmp/aac_asm_%d_%d.ww", getpid(), i);
+	snprintf(cs,  sizeof cs,  "/tmp/aac_asm_%d_%d_c.s", getpid(), i);
+	snprintf(ws,  sizeof ws,  "/tmp/aac_asm_%d_%d_w.s", getpid(), i);
+
+	FILE *f = fopen(src, "wb");
+	if (!f) return -1;
+	fputs(r->src, f);
+	fclose(f);
+
+	snprintf(cmd, sizeof cmd, "%s/w6c -o %s %s 2>/dev/null", bin, cs, src);
+	if (runwait(cmd) != 0) {
+		fprintf(stderr, "row[%s]: w6c errored\n", r->label);
+		unlink(src);
+		return -1;
+	}
+	snprintf(cmd, sizeof cmd, "%s/w6c_ww -o %s %s 2>/dev/null",
+	    bin, ws, src);
+	if (runwait(cmd) != 0) {
+		fprintf(stderr, "row[%s]: w6c_ww errored\n", r->label);
+		unlink(src); unlink(cs);
+		return -1;
+	}
+	int rc = slurp_eq(cs, ws);
+	if (rc != 0)
+		fprintf(stderr, "row[%s]: cstage vs wwstage asm differs\n",
+		    r->label);
+	unlink(src); unlink(cs); unlink(ws);
+	return rc;
+}
+
+int
+main(void)
+{
+	const char *bin = getenv("BIN");
+	if (!bin) bin = "out/bin";
+	char absbin[2080];
+	if (bin[0] != '/') {
+		char cwd[1024];
+		if (getcwd(cwd, sizeof cwd) == NULL) return 1;
+		snprintf(absbin, sizeof absbin, "%s/%s", cwd, bin);
+		bin = absbin;
+	}
+
+	char cdrv[2120], wdrv[2120];
+	snprintf(cdrv, sizeof cdrv, "%s/ww", bin);
+	snprintf(wdrv, sizeof wdrv, "%s/ww_ww", bin);
+
+	int n = (int)(sizeof rows / sizeof rows[0]);
+	int total = 0, fail = 0;
+
+	for (int i = 0; i < n; i++) {
+		total++;
+		if (run_driver(cdrv, &rows[i], i) != 0) fail++;
+	}
+	if (access(wdrv, X_OK) == 0) {
+		for (int i = 0; i < n; i++) {
+			if (rows[i].kind == K_RUN_CS
+			    || rows[i].kind == K_BUILDERR_CS)
+				continue;
+			total++;
+			if (run_driver(wdrv, &rows[i], i) != 0) fail++;
+		}
+		for (int i = 0; i < n; i++) {
+			if (rows[i].kind != K_RUN)
+				continue;
+			total++;
+			if (asm_byte_identical(bin, &rows[i], i) != 0) fail++;
+		}
+	}
+
+	if (fail) {
+		fprintf(stderr, "alias_accept: %d/%d checks failed\n",
+		    fail, total);
+		return 1;
+	}
+	printf("alias_accept: %d/%d ok\n", total, total);
+	return 0;
+}