selfhost+test: route N_DOT base through indexvaluetnode + scanlocals for N_INDEX-lhs cgassign chain (#28+#30)

Wwstage's N_INDEX-lhs cgassign dispatch chain had a triple-site
N_DOT base gap (sister latents filed during #24 / #27 review):

  Read (#28): `obj.mat[i][k]` over a struct field mat: **u8.
  cgindex routes the outer N_INDEX's N_INDEX base through
  indexvaluetnode; the recursion bottomed out at the inner
  N_INDEX's N_DOT base with bt=nil. esz fell through to 8 +
  signed_elem to false — wwstage emitted a stray outer
  `MOVQ $8, CX; IMULQ CX, AX` plus `MOVQ (AX), AX` (8-byte
  read over a 1-byte u8) instead of cstage's bare
  `MOVZBQ (AX), AX`.

  Write (#30): `obj.arr[i] = v` over a struct field arr:
  [N]Tagged (e.g. (i64|str)). cgassign's N_DOT-base arm
  computed esz via indexbaseesz but never set elemtn, so the
  tagged-element store gate missed and the 24-byte tagged slot
  was overwritten by a single scalar MOVQ — wrong-width store
  + tag/payload junk in the upper 16 bytes.

Cstage walks `n->lhs->type` directly via the typed AST
(cmd/w6c/cgen.c idx_eff + the N_INDEX-lhs N_ASSIGN branch).
Wwstage now mirrors via indexvaluetnode, which #24 (aa8ca47)
introduced for the N_INDEX-base case; #28/#30 graduate it for
N_DOT base via the existing dotfieldtnode helper.

Bundle graduates N_DOT base for the entire N_INDEX-lhs cgassign
chain: (a) indexvaluetnode in cgenutil.ww handles N_DOT base via
dotfieldtnode; (b) cgassign N_DOT-base arm in cgenexpr.ww calls
indexvaluetnode for elemtn; (c) scanlocals N_DOT-base arm in
cgendecl.ww parallels the existing N_IDENT arm for tagscr-bump.
Splits are bisect-incoherent: (b)-alone clobbers locals via
under-sized frame, (a)-alone leaves the write path with wrong
elemtn, (c)-alone has no consumer. Only the triple delivers a
complete N_DOT-base graduation matching #24's N_INDEX-base
pattern.

Cstage's first-use+fail-loud strategy for @tagscr (#26 commit
069548d) handles the N_DOT-base shape naturally; the scanlocals
N_DOT arm is wwstage-specific. Long-term rule-10 convergence
(wwstage DOWN from scanlocals to first-use+fail-loud on BOTH
stages) is filed as task #15.

Class A wwstage cgen UNDER. No in-tree consumer; sister latents
filed during #24 + #27 reviews. Test 741_dotbase_chained pins
the dispatch + cstage-byte-identical asm for both rows.

Sister latent (filed): indexbaseesz has no N_TARRAY arm for
scalar struct-field array writes — `s.arr: [N]i32` scalar write
falls through to esz=8 on wwstage. No in-tree exerciser; tight
scope kept here.

115/115 ok. ww2 == ww3 == ww4 byte-id.

Makefile

@@ -268,6 +268,7 @@ TESTS	= $(BIN)/test_smoke $(BIN)/test_lex $(BIN)/test_parse $(BIN)/test_check \
 	  $(BIN)/test_module_decl \
 	  $(BIN)/test_chained_index \
 	  $(BIN)/test_chained_write \
+	  $(BIN)/test_dotbase_chained \
 	  $(BIN)/test_fnparams_bare_leaf_shadow \
 	  $(BIN)/test_fnret_bare_leaf_shadow \
 	  $(BIN)/test_param_shadow_mod \
@@ -649,6 +650,10 @@ $(BIN)/test_chained_write: test/wcc/740_chained_write.c \
 		$(BIN)/w6c $(BIN)/w6c_ww | $(BIN)
 	$(CC) $(CFLAGS) -o $@ $<
 
+$(BIN)/test_dotbase_chained: test/wcc/741_dotbase_chained.c \
+		$(BIN)/w6c $(BIN)/w6c_ww | $(BIN)
+	$(CC) $(CFLAGS) -o $@ $<
+
 $(BIN)/test_fnparams_bare_leaf_shadow: test/wcc/732_fnparams_bare_leaf_shadow.c \
 		$(BIN)/w6c $(BIN)/w6c_ww | $(BIN)
 	$(CC) $(CFLAGS) -o $@ $<

selfhost/cmd/w6c/main.combined.ww

@@ -8208,6 +8208,9 @@ fn elemsizeofc(c: *cgen, t: *node) i32 = {
 // the outer base type to *u8 (the post-inner-index value type), so
 // cgindex can compute the outer element size honestly. Mirrors
 // cstage's `n->lhs->type` via typed-AST (cmd/w6c/cgen.c idx_eff).
+// N_DOT base graduated (tasks #28/#30) so `obj.mat[i][k]` reads
+// and `obj.arr[i] = v` tagged-element writes route through the
+// same helper as the N_IDENT/N_INDEX bases #24/#27 graduated.
 fn indexvaluetnode(c: *cgen, n: *node) *node = {
 	if (n == nil) { return nil; };
 	if (n.kind != nkind.N_INDEX) { return nil; };
@@ -8220,6 +8223,7 @@ fn indexvaluetnode(c: *cgen, n: *node) *node = {
 		else           { bt = letvartnode(c, base.str); };
 	};
 	if (base.kind == nkind.N_INDEX) { bt = indexvaluetnode(c, base); };
+	if (base.kind == nkind.N_DOT)   { bt = dotfieldtnode(c, base); };
 	if (bt == nil) { return nil; };
 	let k: nkind = bt.kind;
 	if (k == nkind.N_TPTR)   { return bt.lhs; };
@@ -14242,6 +14246,16 @@ fn cgassign(c: *cgen, n: *node) void = {
 						};
 					} else { if (base.kind == nkind.N_DOT) {
 						esz = indexbaseesz(c, base);
+						// Without this, the tagged-element gate
+						// below (keyed on elemtn) misses for
+						// `obj.arr[i] = v` over an [N]Tagged field
+						// and the store falls through to scalar —
+						// task #30, sister of the cgindex N_INDEX-
+						// base fix #24. indexvaluetnode now handles
+						// N_DOT base, so the element type drops out
+						// of the same helper.
+						let bt: *node = indexvaluetnode(c, lhs);
+						if (bt != nil) { elemtn = bt; };
 					} else { if (base.kind == nkind.N_INDEX) {
 						// Chained-write write-side parallel of the
 						// cgindex N_INDEX-base arm graduated in #24:
@@ -18010,6 +18024,12 @@ fn scanlocals(c: *cgen, n: *node) i32 = {
 	// cgwidentaggedstore to materialise the source in before copying
 	// to the element address. Slot is shared per function via
 	// c.tagscrsz (raised to the largest element slot_sz seen).
+	// N_DOT-base graduated (task #30) so `obj.arr[i] = v` for an
+	// [N]Tagged struct field pre-reserves the slot — parallels the
+	// cgassign N_DOT-base elemtn fix in cgenexpr.ww. Without this
+	// arm the runtime localadd allocates past the frame boundary
+	// and clobbers live locals; cstage handles the shape naturally
+	// via first-use+fail-loud (rule-10 convergence filed as #15).
 	if (n.kind == nkind.N_ASSIGN) {
 		let alhs: *node = n.lhs;
 		if (alhs != nil) {
@@ -18034,6 +18054,21 @@ fn scanlocals(c: *cgen, n: *node) i32 = {
 							};
 						};
 					};
+					if (abase.kind == nkind.N_DOT) {
+						let ft: *node = dotfieldtnode(c, abase);
+						if (ft != nil) {
+							let bk: nkind = ft.kind;
+							let etn: *node = nil;
+							if (bk == nkind.N_TARRAY) { etn = ft.lhs; };
+							if (bk == nkind.N_TSLICE) { etn = ft.lhs; };
+							if (bk == nkind.N_TPTR)   { etn = ft.lhs; };
+							if (etn != nil) {
+								if (istaggedtype(c, etn)) {
+									total += tagscrbump(c, slotsize(c, etn));
+								};
+							};
+						};
+					};
 				};
 			};
 		};

selfhost/cmd/wcc/cgendecl.ww

@@ -241,6 +241,12 @@ fn scanlocals(c: *cgen, n: *node) i32 = {
 	// cgwidentaggedstore to materialise the source in before copying
 	// to the element address. Slot is shared per function via
 	// c.tagscrsz (raised to the largest element slot_sz seen).
+	// N_DOT-base graduated (task #30) so `obj.arr[i] = v` for an
+	// [N]Tagged struct field pre-reserves the slot — parallels the
+	// cgassign N_DOT-base elemtn fix in cgenexpr.ww. Without this
+	// arm the runtime localadd allocates past the frame boundary
+	// and clobbers live locals; cstage handles the shape naturally
+	// via first-use+fail-loud (rule-10 convergence filed as #15).
 	if (n.kind == nkind.N_ASSIGN) {
 		let alhs: *node = n.lhs;
 		if (alhs != nil) {
@@ -265,6 +271,21 @@ fn scanlocals(c: *cgen, n: *node) i32 = {
 							};
 						};
 					};
+					if (abase.kind == nkind.N_DOT) {
+						let ft: *node = dotfieldtnode(c, abase);
+						if (ft != nil) {
+							let bk: nkind = ft.kind;
+							let etn: *node = nil;
+							if (bk == nkind.N_TARRAY) { etn = ft.lhs; };
+							if (bk == nkind.N_TSLICE) { etn = ft.lhs; };
+							if (bk == nkind.N_TPTR)   { etn = ft.lhs; };
+							if (etn != nil) {
+								if (istaggedtype(c, etn)) {
+									total += tagscrbump(c, slotsize(c, etn));
+								};
+							};
+						};
+					};
 				};
 			};
 		};

selfhost/cmd/wcc/cgenexpr.ww

@@ -3518,6 +3518,16 @@ fn cgassign(c: *cgen, n: *node) void = {
 						};
 					} else { if (base.kind == nkind.N_DOT) {
 						esz = indexbaseesz(c, base);
+						// Without this, the tagged-element gate
+						// below (keyed on elemtn) misses for
+						// `obj.arr[i] = v` over an [N]Tagged field
+						// and the store falls through to scalar —
+						// task #30, sister of the cgindex N_INDEX-
+						// base fix #24. indexvaluetnode now handles
+						// N_DOT base, so the element type drops out
+						// of the same helper.
+						let bt: *node = indexvaluetnode(c, lhs);
+						if (bt != nil) { elemtn = bt; };
 					} else { if (base.kind == nkind.N_INDEX) {
 						// Chained-write write-side parallel of the
 						// cgindex N_INDEX-base arm graduated in #24:

selfhost/cmd/wcc/cgenutil.ww

@@ -1247,6 +1247,9 @@ fn elemsizeofc(c: *cgen, t: *node) i32 = {
 // the outer base type to *u8 (the post-inner-index value type), so
 // cgindex can compute the outer element size honestly. Mirrors
 // cstage's `n->lhs->type` via typed-AST (cmd/w6c/cgen.c idx_eff).
+// N_DOT base graduated (tasks #28/#30) so `obj.mat[i][k]` reads
+// and `obj.arr[i] = v` tagged-element writes route through the
+// same helper as the N_IDENT/N_INDEX bases #24/#27 graduated.
 fn indexvaluetnode(c: *cgen, n: *node) *node = {
 	if (n == nil) { return nil; };
 	if (n.kind != nkind.N_INDEX) { return nil; };
@@ -1259,6 +1262,7 @@ fn indexvaluetnode(c: *cgen, n: *node) *node = {
 		else           { bt = letvartnode(c, base.str); };
 	};
 	if (base.kind == nkind.N_INDEX) { bt = indexvaluetnode(c, base); };
+	if (base.kind == nkind.N_DOT)   { bt = dotfieldtnode(c, base); };
 	if (bt == nil) { return nil; };
 	let k: nkind = bt.kind;
 	if (k == nkind.N_TPTR)   { return bt.lhs; };

selfhost/cmd/wwdump/main.combined.ww

@@ -8208,6 +8208,9 @@ fn elemsizeofc(c: *cgen, t: *node) i32 = {
 // the outer base type to *u8 (the post-inner-index value type), so
 // cgindex can compute the outer element size honestly. Mirrors
 // cstage's `n->lhs->type` via typed-AST (cmd/w6c/cgen.c idx_eff).
+// N_DOT base graduated (tasks #28/#30) so `obj.mat[i][k]` reads
+// and `obj.arr[i] = v` tagged-element writes route through the
+// same helper as the N_IDENT/N_INDEX bases #24/#27 graduated.
 fn indexvaluetnode(c: *cgen, n: *node) *node = {
 	if (n == nil) { return nil; };
 	if (n.kind != nkind.N_INDEX) { return nil; };
@@ -8220,6 +8223,7 @@ fn indexvaluetnode(c: *cgen, n: *node) *node = {
 		else           { bt = letvartnode(c, base.str); };
 	};
 	if (base.kind == nkind.N_INDEX) { bt = indexvaluetnode(c, base); };
+	if (base.kind == nkind.N_DOT)   { bt = dotfieldtnode(c, base); };
 	if (bt == nil) { return nil; };
 	let k: nkind = bt.kind;
 	if (k == nkind.N_TPTR)   { return bt.lhs; };
@@ -14242,6 +14246,16 @@ fn cgassign(c: *cgen, n: *node) void = {
 						};
 					} else { if (base.kind == nkind.N_DOT) {
 						esz = indexbaseesz(c, base);
+						// Without this, the tagged-element gate
+						// below (keyed on elemtn) misses for
+						// `obj.arr[i] = v` over an [N]Tagged field
+						// and the store falls through to scalar —
+						// task #30, sister of the cgindex N_INDEX-
+						// base fix #24. indexvaluetnode now handles
+						// N_DOT base, so the element type drops out
+						// of the same helper.
+						let bt: *node = indexvaluetnode(c, lhs);
+						if (bt != nil) { elemtn = bt; };
 					} else { if (base.kind == nkind.N_INDEX) {
 						// Chained-write write-side parallel of the
 						// cgindex N_INDEX-base arm graduated in #24:
@@ -18010,6 +18024,12 @@ fn scanlocals(c: *cgen, n: *node) i32 = {
 	// cgwidentaggedstore to materialise the source in before copying
 	// to the element address. Slot is shared per function via
 	// c.tagscrsz (raised to the largest element slot_sz seen).
+	// N_DOT-base graduated (task #30) so `obj.arr[i] = v` for an
+	// [N]Tagged struct field pre-reserves the slot — parallels the
+	// cgassign N_DOT-base elemtn fix in cgenexpr.ww. Without this
+	// arm the runtime localadd allocates past the frame boundary
+	// and clobbers live locals; cstage handles the shape naturally
+	// via first-use+fail-loud (rule-10 convergence filed as #15).
 	if (n.kind == nkind.N_ASSIGN) {
 		let alhs: *node = n.lhs;
 		if (alhs != nil) {
@@ -18034,6 +18054,21 @@ fn scanlocals(c: *cgen, n: *node) i32 = {
 							};
 						};
 					};
+					if (abase.kind == nkind.N_DOT) {
+						let ft: *node = dotfieldtnode(c, abase);
+						if (ft != nil) {
+							let bk: nkind = ft.kind;
+							let etn: *node = nil;
+							if (bk == nkind.N_TARRAY) { etn = ft.lhs; };
+							if (bk == nkind.N_TSLICE) { etn = ft.lhs; };
+							if (bk == nkind.N_TPTR)   { etn = ft.lhs; };
+							if (etn != nil) {
+								if (istaggedtype(c, etn)) {
+									total += tagscrbump(c, slotsize(c, etn));
+								};
+							};
+						};
+					};
 				};
 			};
 		};

test/wcc/741_dotbase_chained.c

@@ -0,0 +1,239 @@
+/*
+ * 741_dotbase_chained — sentinel for #28 + #30. Pins wwstage's
+ * `indexvaluetnode` to handle N_DOT base (graduates the helper #24
+ * introduced for chained N_INDEX so the N_DOT base shape rides the
+ * same path).
+ *
+ * Two sister latents, one helper graduation:
+ *
+ *   Read (#28): `obj.mat[i][k]` where obj is a struct with field
+ *   `mat: **u8`. The outer N_INDEX's base is the inner N_INDEX,
+ *   whose base is N_DOT. cgindex routes through `indexvaluetnode`
+ *   for the inner base type; pre-fix `indexvaluetnode` only handled
+ *   N_IDENT + N_INDEX bases, so the recursion bottomed out at the
+ *   N_DOT base with bt=nil. esz fell through to 8 and signed_elem
+ *   to false — wwstage emitted a stray outer `MOVQ $8, CX; IMULQ
+ *   CX, AX` plus `MOVQ (AX), AX` (8-byte read over a 1-byte u8)
+ *   instead of cstage's bare `MOVZBQ (AX), AX`.
+ *
+ *   Write (#30): `obj.arr[i] = v` where obj is a struct with field
+ *   `arr: [N]Tagged` (e.g. (i64|str)). cgassign's N_DOT-base arm
+ *   computed esz via `indexbaseesz` but never set `elemtn`, so the
+ *   tagged-element store gate (keyed on elemtn) missed and the
+ *   24-byte tagged slot was overwritten by a single MOVQ scalar
+ *   store — wrong-width store + tag/payload junk in the upper
+ *   16 bytes. The matching scanlocals pre-pass arm (cgendecl.ww)
+ *   was also missing N_DOT base, so post-elemtn-fix the @tagscr
+ *   slot allocated past the frame boundary and clobbered live
+ *   locals (s, i).
+ *
+ * Cstage walks `n->lhs->type` directly via the typed AST (cmd/w6c/
+ * cgen.c idx_eff + the N_INDEX-lhs N_ASSIGN branch). Wwstage
+ * mirrors via `indexvaluetnode`, which #24 introduced for the
+ * N_INDEX-base case and #28/#30 now graduate for N_DOT base via
+ * `dotfieldtnode` lookup.
+ *
+ * Class A wwstage cgen UNDER. No in-tree consumer; sister latents
+ * filed during #24 + #27 reviews (commits aa8ca47, 3ba1922). This
+ * sentinel is the sole exerciser of the shape.
+ *
+ * Per row: in the `probe` body, assert the dispatch-defining MOV
+ * mnemonic + scaling is present, plus cstage vs wwstage asm is
+ * byte-identical.
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.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;
+}
+
+/* `needle` = a substring that must appear in the probe body and
+ * uniquely identifies the post-fix dispatch (narrow MOV mnemonic
+ * for read, 24B element scale for tagged write).
+ * `antineedle` = a substring that MUST NOT appear — pre-fix wwstage
+ * regression marker. Empty string skips the anti-check (write row
+ * relies on cmp -s byte-id to catch divergence, since the tagged-
+ * store byte-copy legitimately contains MOVQ-store fragments). */
+struct row {
+	const char *label;
+	const char *src;
+	const char *needle;
+	const char *antineedle;
+};
+
+static const struct row rows[] = {
+	/* Read: chained `obj.mat[i][k]` where mat: **u8. Post-fix wwstage
+	 * routes the inner N_INDEX's N_DOT base through indexvaluetnode →
+	 * dotfieldtnode, esz collapses to 1, outer load becomes MOVZBQ.
+	 * Pre-fix had stray `MOVQ (AX), AX` (8-byte read over u8). */
+	{ "dotbase_chained_read",
+	  "type S = struct{ pad: i64, mat: **u8 };\n"
+	  "fn probe(s: *S) u8 = {\n"
+	  "    let i: i32 = 0;\n"
+	  "    let k: u64 = 0u64;\n"
+	  "    return s.mat[i][k];\n"
+	  "};\n"
+	  "export fn main() i32 = { return 0; };\n",
+	  "\tMOVZBQ\t(AX), AX\n",
+	  "" },
+	/* Write: `obj.arr[i] = v` where arr: [N](i64|str) — 24B tagged.
+	 * Post-fix wwstage: cgassign N_DOT arm sets elemtn → tagged-store
+	 * path → IMULQ $24 + byte-copy from scratch. Scanlocals N_DOT arm
+	 * pre-reserves @tagscr in the frame. Pre-fix: scalar `MOVQ AX,
+	 * (BX)` over the 24B slot. */
+	{ "dotbase_array_tagged_write",
+	  "type T = (i64 | str);\n"
+	  "type S = struct{ pad: i64, arr: [4]T };\n"
+	  "fn probe(s: *S) void = {\n"
+	  "    let i: i32 = 0;\n"
+	  "    s.arr[i] = 42i64;\n"
+	  "};\n"
+	  "export fn main() i32 = { return 0; };\n",
+	  "\tMOVQ\t$24, CX\n",
+	  "" },
+};
+
+static int
+slurp(const char *path, char *buf, size_t cap)
+{
+	FILE *f = fopen(path, "rb");
+	if (!f) return -1;
+	size_t n = fread(buf, 1, cap - 1, f);
+	fclose(f);
+	buf[n] = '\0';
+	return (int)n;
+}
+
+static int
+emit_s(const char *w6c, const struct row *r, int i, char *out_s, size_t cap)
+{
+	char src[96], cmd[1024];
+	snprintf(src, sizeof src, "/tmp/dotbase_%d_%d.ww", getpid(), i);
+	snprintf(out_s, cap, "/tmp/dotbase_%d_%d_%s.s",
+	    getpid(), i, w6c[strlen(w6c) - 1] == 'w' ? "ww" : "c");
+
+	FILE *f = fopen(src, "wb");
+	if (!f) return -1;
+	fputs(r->src, f);
+	fclose(f);
+
+	snprintf(cmd, sizeof cmd, "%s -o %s %s 2>/dev/null", w6c, out_s, src);
+	int rc = runwait(cmd);
+	unlink(src);
+	return rc;
+}
+
+/* Inside `TEXT probe`, the needle must appear and the antineedle
+ * must NOT appear (anti-regression on pre-fix wwstage emit). */
+static int
+check_probe(const char *spath, const struct row *r, const char *stage)
+{
+	char buf[1 << 14];
+	if (slurp(spath, buf, sizeof buf) < 0) {
+		fprintf(stderr, "row[%s][%s]: cannot read %s\n",
+		    r->label, stage, spath);
+		return -1;
+	}
+	const char *fn = strstr(buf, "TEXT probe");
+	if (!fn) {
+		fprintf(stderr,
+		    "row[%s][%s]: no TEXT probe in %s\n",
+		    r->label, stage, spath);
+		return -1;
+	}
+	const char *ret = strstr(fn, "\tRET\n");
+	const char *m = strstr(fn, r->needle);
+	if (!m || (ret && m > ret)) {
+		fprintf(stderr,
+		    "row[%s][%s]: expected `%s` in probe body\n",
+		    r->label, stage, r->needle);
+		return -1;
+	}
+	if (r->antineedle[0] != '\0') {
+		const char *bad = strstr(fn, r->antineedle);
+		if (bad && (!ret || bad < ret)) {
+			fprintf(stderr,
+			    "row[%s][%s]: stray `%s` in probe body — "
+			    "pre-fix wwstage regression\n",
+			    r->label, stage, r->antineedle);
+			return -1;
+		};
+	}
+	return 0;
+}
+
+int
+main(void)
+{
+	const char *bin = getenv("BIN");
+	if (!bin) bin = "out/bin";
+	char absbin[512];
+	if (bin[0] != '/') {
+		char cwd[256];
+		if (getcwd(cwd, sizeof cwd) == NULL) return 1;
+		snprintf(absbin, sizeof absbin, "%s/%s", cwd, bin);
+		bin = absbin;
+	}
+
+	char w6c[640], w6c_ww[640];
+	snprintf(w6c, sizeof w6c, "%s/w6c", bin);
+	snprintf(w6c_ww, sizeof w6c_ww, "%s/w6c_ww", bin);
+
+	int have_ww = (access(w6c_ww, X_OK) == 0);
+	int n = (int)(sizeof rows / sizeof rows[0]);
+	int total = 0, fail = 0;
+
+	for (int i = 0; i < n; i++) {
+		char cs_path[128], ws_path[128];
+
+		if (emit_s(w6c, &rows[i], i, cs_path, sizeof cs_path) != 0) {
+			fprintf(stderr,
+			    "dotbase_chained[cstage][%s]: w6c failed\n",
+			    rows[i].label);
+			fail++; total++; continue;
+		}
+		total++;
+		if (check_probe(cs_path, &rows[i], "cstage") != 0) fail++;
+
+		if (!have_ww) { unlink(cs_path); continue; }
+
+		if (emit_s(w6c_ww, &rows[i], i, ws_path, sizeof ws_path) != 0) {
+			fprintf(stderr,
+			    "dotbase_chained[wwstage][%s]: w6c_ww failed\n",
+			    rows[i].label);
+			fail++; total++;
+			unlink(cs_path); continue;
+		}
+		total++;
+		if (check_probe(ws_path, &rows[i], "wwstage") != 0) fail++;
+
+		total++;
+		char cmd[512];
+		snprintf(cmd, sizeof cmd, "cmp -s %s %s", cs_path, ws_path);
+		if (runwait(cmd) != 0) {
+			fprintf(stderr,
+			    "dotbase_chained[%s]: cstage vs wwstage asm differs\n",
+			    rows[i].label);
+			fail++;
+		}
+
+		unlink(cs_path); unlink(ws_path);
+	}
+
+	if (fail) {
+		fprintf(stderr,
+		    "dotbase_chained: %d/%d fixtures failed\n", fail, total);
+		return 1;
+	}
+	printf("dotbase_chained: %d/%d ok\n", total, total);
+	return 0;
+}