wcc/ww: def-dim array .len field-reads resolve the dimension from the type table

buf.len on a [MAX]u8 returned 0 — the cgdot len arms (local/global/
def) and letemitsize only read an N_INTLIT dimension. Route a
non-literal dimension through tichase().alen (the #21 fix mirrored
into the field-read consumers; .ptr arms are dim-independent).
Review-era task #56.

Makefile

@@ -257,6 +257,7 @@ TESTS	= $(BIN)/test_smoke $(BIN)/test_lex $(BIN)/test_parse $(BIN)/test_check \
 	  $(BIN)/test_defdim_slice_run \
 	  $(BIN)/test_trystr_run \
 	  $(BIN)/test_allocalias_run \
+	  $(BIN)/test_defdim_field_run \
 	  $(BIN)/test_gunsigned_run \
 	  $(BIN)/test_taggedidx_run \
 	  $(BIN)/test_fnptrcollide_run \
@@ -757,6 +758,17 @@ $(BIN)/test_allocalias_run: test/wcc/989_allocalias_run.c \
 		$(LIB)/libwwrt.a | $(BIN)
 	$(CC) $(CFLAGS) -o $@ $<
 
+# 989_defdim_field_run (#56): `.len` field-read on a `def`-dimensioned array
+# (`[MAX]T`) resolves the length from the type table in the local/global/def
+# cgdot arms + letemitsize (cgdot sibling of #21). Builds+runs on BOTH driver
+# twins (rule-10).
+$(BIN)/test_defdim_field_run: test/wcc/989_defdim_field_run.c \
+		$(BIN)/ww $(BIN)/ww_ww \
+		$(BIN)/w6c $(BIN)/w6a $(BIN)/w6l \
+		$(BIN)/w6c_ww $(BIN)/w6a_ww $(BIN)/w6l_ww \
+		$(LIB)/libwwrt.a | $(BIN)
+	$(CC) $(CFLAGS) -o $@ $<
+
 # 989_gunsigned_run (F7-c5, #25): a module-global unsigned ident on the
 # divide/shift/relational path must pick the unsigned opcode. Builds+runs on
 # BOTH driver twins (rule-10). CLASS-M — see the test header.

selfhost/cmd/w6c/main.combined.ww

@@ -26664,8 +26664,19 @@ fn cgdot(c: *cgen, n: *node) void = {
 					if (streq(fld, "len")) {
 						let lenn: *node = tn.rhs;
 						let alen: i64 = 0i64;
-						if (lenn != nil) {
-							if (lenn.kind == nkind.N_INTLIT) { alen = lenn.uval: i64; };
+						if (lenn != nil && lenn.kind == nkind.N_INTLIT) {
+							alen = lenn.uval: i64;
+						} else {
+							// #56: def/const dim — resolve from the
+							// stamped array tinfo (rule-13), the field-
+							// read twin of the #21 cgslice fix. The dim
+							// node is an N_IDENT(def), not N_INTLIT, so
+							// the literal read above defaults 0; cstage
+							// reads the resolved bu->alen.
+							let abt: *tinfo = tichase(tn.type_: *tinfo);
+							if (abt != nil && abt.kind == tykind.TY_ARRAY) {
+								alen = abt.alen: i64;
+							};
 						};
 						emitline("\tMOVQ\t$");
 						emitint(alen);
@@ -26899,9 +26910,15 @@ fn cgdot(c: *cgen, n: *node) void = {
 					if (streq(fld, "len")) {
 						let lenn: *node = gtn.rhs;
 						let alen: i64 = 0i64;
-						if (lenn != nil) {
-							if (lenn.kind == nkind.N_INTLIT) {
-								alen = lenn.uval: i64;
+						if (lenn != nil && lenn.kind == nkind.N_INTLIT) {
+							alen = lenn.uval: i64;
+						} else {
+							// #56: def/const dim on a let-global array —
+							// resolve from the stamped array tinfo
+							// (rule-13), twin of the local arm above.
+							let abt: *tinfo = tichase(gtn.type_: *tinfo);
+							if (abt != nil && abt.kind == tykind.TY_ARRAY) {
+								alen = abt.alen: i64;
 							};
 						};
 						emitline("\tMOVQ\t$");
@@ -26943,9 +26960,15 @@ fn cgdot(c: *cgen, n: *node) void = {
 					if (dtn.kind == nkind.N_TARRAY) {
 						let lenn: *node = dtn.rhs;
 						let alen: i64 = 0i64;
-						if (lenn != nil) {
-							if (lenn.kind == nkind.N_INTLIT) {
-								alen = lenn.uval: i64;
+						if (lenn != nil && lenn.kind == nkind.N_INTLIT) {
+							alen = lenn.uval: i64;
+						} else {
+							// #56: def/const dim on a def array —
+							// resolve from the stamped array tinfo
+							// (rule-13), twin of the let-global arm above.
+							let abt: *tinfo = tichase(dtn.type_: *tinfo);
+							if (abt != nil && abt.kind == tykind.TY_ARRAY) {
+								alen = abt.alen: i64;
 							};
 						};
 						emitline("\tMOVQ\t$");
@@ -41524,8 +41547,17 @@ fn letemitsize(c: *cgen, d: *node) i32 = {
 			let lenn: *node = t.rhs;
 			let elemn: *node = t.lhs;
 			let alen: i32 = 1;
-			if (lenn != nil) {
-				if (lenn.kind == nkind.N_INTLIT) { alen = lenn.uval: i32; };
+			if (lenn != nil && lenn.kind == nkind.N_INTLIT) {
+				alen = lenn.uval: i32;
+			} else {
+				// #56: def/const dim — resolve from the stamped array
+				// tinfo (rule-13), the letemitsize twin of the cgdot
+				// .len fix. Pre-fix a non-N_INTLIT dim defaulted alen=1
+				// → array global mis-sized (one element's worth).
+				let abt: *tinfo = tichase(t.type_: *tinfo);
+				if (abt != nil && abt.kind == tykind.TY_ARRAY) {
+					alen = abt.alen: i32;
+				};
 			};
 			let esz: i32 = 8;
 			if (elemn != nil) {

selfhost/cmd/wcc/cgen.ww

@@ -1004,8 +1004,17 @@ fn letemitsize(c: *cgen, d: *node) i32 = {
 			let lenn: *node = t.rhs;
 			let elemn: *node = t.lhs;
 			let alen: i32 = 1;
-			if (lenn != nil) {
-				if (lenn.kind == nkind.N_INTLIT) { alen = lenn.uval: i32; };
+			if (lenn != nil && lenn.kind == nkind.N_INTLIT) {
+				alen = lenn.uval: i32;
+			} else {
+				// #56: def/const dim — resolve from the stamped array
+				// tinfo (rule-13), the letemitsize twin of the cgdot
+				// .len fix. Pre-fix a non-N_INTLIT dim defaulted alen=1
+				// → array global mis-sized (one element's worth).
+				let abt: *tinfo = tichase(t.type_: *tinfo);
+				if (abt != nil && abt.kind == tykind.TY_ARRAY) {
+					alen = abt.alen: i32;
+				};
 			};
 			let esz: i32 = 8;
 			if (elemn != nil) {

selfhost/cmd/wcc/cgenexpr.ww

@@ -3444,8 +3444,19 @@ fn cgdot(c: *cgen, n: *node) void = {
 					if (streq(fld, "len")) {
 						let lenn: *node = tn.rhs;
 						let alen: i64 = 0i64;
-						if (lenn != nil) {
-							if (lenn.kind == nkind.N_INTLIT) { alen = lenn.uval: i64; };
+						if (lenn != nil && lenn.kind == nkind.N_INTLIT) {
+							alen = lenn.uval: i64;
+						} else {
+							// #56: def/const dim — resolve from the
+							// stamped array tinfo (rule-13), the field-
+							// read twin of the #21 cgslice fix. The dim
+							// node is an N_IDENT(def), not N_INTLIT, so
+							// the literal read above defaults 0; cstage
+							// reads the resolved bu->alen.
+							let abt: *tinfo = tichase(tn.type_: *tinfo);
+							if (abt != nil && abt.kind == tykind.TY_ARRAY) {
+								alen = abt.alen: i64;
+							};
 						};
 						emitline("\tMOVQ\t$");
 						emitint(alen);
@@ -3679,9 +3690,15 @@ fn cgdot(c: *cgen, n: *node) void = {
 					if (streq(fld, "len")) {
 						let lenn: *node = gtn.rhs;
 						let alen: i64 = 0i64;
-						if (lenn != nil) {
-							if (lenn.kind == nkind.N_INTLIT) {
-								alen = lenn.uval: i64;
+						if (lenn != nil && lenn.kind == nkind.N_INTLIT) {
+							alen = lenn.uval: i64;
+						} else {
+							// #56: def/const dim on a let-global array —
+							// resolve from the stamped array tinfo
+							// (rule-13), twin of the local arm above.
+							let abt: *tinfo = tichase(gtn.type_: *tinfo);
+							if (abt != nil && abt.kind == tykind.TY_ARRAY) {
+								alen = abt.alen: i64;
 							};
 						};
 						emitline("\tMOVQ\t$");
@@ -3723,9 +3740,15 @@ fn cgdot(c: *cgen, n: *node) void = {
 					if (dtn.kind == nkind.N_TARRAY) {
 						let lenn: *node = dtn.rhs;
 						let alen: i64 = 0i64;
-						if (lenn != nil) {
-							if (lenn.kind == nkind.N_INTLIT) {
-								alen = lenn.uval: i64;
+						if (lenn != nil && lenn.kind == nkind.N_INTLIT) {
+							alen = lenn.uval: i64;
+						} else {
+							// #56: def/const dim on a def array —
+							// resolve from the stamped array tinfo
+							// (rule-13), twin of the let-global arm above.
+							let abt: *tinfo = tichase(dtn.type_: *tinfo);
+							if (abt != nil && abt.kind == tykind.TY_ARRAY) {
+								alen = abt.alen: i64;
 							};
 						};
 						emitline("\tMOVQ\t$");

selfhost/cmd/wwdump/main.combined.ww

@@ -26664,8 +26664,19 @@ fn cgdot(c: *cgen, n: *node) void = {
 					if (streq(fld, "len")) {
 						let lenn: *node = tn.rhs;
 						let alen: i64 = 0i64;
-						if (lenn != nil) {
-							if (lenn.kind == nkind.N_INTLIT) { alen = lenn.uval: i64; };
+						if (lenn != nil && lenn.kind == nkind.N_INTLIT) {
+							alen = lenn.uval: i64;
+						} else {
+							// #56: def/const dim — resolve from the
+							// stamped array tinfo (rule-13), the field-
+							// read twin of the #21 cgslice fix. The dim
+							// node is an N_IDENT(def), not N_INTLIT, so
+							// the literal read above defaults 0; cstage
+							// reads the resolved bu->alen.
+							let abt: *tinfo = tichase(tn.type_: *tinfo);
+							if (abt != nil && abt.kind == tykind.TY_ARRAY) {
+								alen = abt.alen: i64;
+							};
 						};
 						emitline("\tMOVQ\t$");
 						emitint(alen);
@@ -26899,9 +26910,15 @@ fn cgdot(c: *cgen, n: *node) void = {
 					if (streq(fld, "len")) {
 						let lenn: *node = gtn.rhs;
 						let alen: i64 = 0i64;
-						if (lenn != nil) {
-							if (lenn.kind == nkind.N_INTLIT) {
-								alen = lenn.uval: i64;
+						if (lenn != nil && lenn.kind == nkind.N_INTLIT) {
+							alen = lenn.uval: i64;
+						} else {
+							// #56: def/const dim on a let-global array —
+							// resolve from the stamped array tinfo
+							// (rule-13), twin of the local arm above.
+							let abt: *tinfo = tichase(gtn.type_: *tinfo);
+							if (abt != nil && abt.kind == tykind.TY_ARRAY) {
+								alen = abt.alen: i64;
 							};
 						};
 						emitline("\tMOVQ\t$");
@@ -26943,9 +26960,15 @@ fn cgdot(c: *cgen, n: *node) void = {
 					if (dtn.kind == nkind.N_TARRAY) {
 						let lenn: *node = dtn.rhs;
 						let alen: i64 = 0i64;
-						if (lenn != nil) {
-							if (lenn.kind == nkind.N_INTLIT) {
-								alen = lenn.uval: i64;
+						if (lenn != nil && lenn.kind == nkind.N_INTLIT) {
+							alen = lenn.uval: i64;
+						} else {
+							// #56: def/const dim on a def array —
+							// resolve from the stamped array tinfo
+							// (rule-13), twin of the let-global arm above.
+							let abt: *tinfo = tichase(dtn.type_: *tinfo);
+							if (abt != nil && abt.kind == tykind.TY_ARRAY) {
+								alen = abt.alen: i64;
 							};
 						};
 						emitline("\tMOVQ\t$");
@@ -41524,8 +41547,17 @@ fn letemitsize(c: *cgen, d: *node) i32 = {
 			let lenn: *node = t.rhs;
 			let elemn: *node = t.lhs;
 			let alen: i32 = 1;
-			if (lenn != nil) {
-				if (lenn.kind == nkind.N_INTLIT) { alen = lenn.uval: i32; };
+			if (lenn != nil && lenn.kind == nkind.N_INTLIT) {
+				alen = lenn.uval: i32;
+			} else {
+				// #56: def/const dim — resolve from the stamped array
+				// tinfo (rule-13), the letemitsize twin of the cgdot
+				// .len fix. Pre-fix a non-N_INTLIT dim defaulted alen=1
+				// → array global mis-sized (one element's worth).
+				let abt: *tinfo = tichase(t.type_: *tinfo);
+				if (abt != nil && abt.kind == tykind.TY_ARRAY) {
+					alen = abt.alen: i32;
+				};
 			};
 			let esz: i32 = 8;
 			if (elemn != nil) {

test/wcc/989_defdim_field_run.c

@@ -0,0 +1,170 @@
+/*
+ * 989_defdim_field_run (#56) — `.len` field-read on an array whose dimension
+ * is a `def` constant (`[MAX]T`) must resolve the length from the type table,
+ * the cgdot sibling of the #21 cgslice fix.
+ *
+ * THE BUG (wwstage only): the cgdot `.len` arms (local / let-global / def) and
+ * letemitsize read the array dimension straight off the AST tnode and only
+ * handled an N_INTLIT dim. A `def MAX` dim arrives as a non-literal node, so
+ * `.len` folded to MOVQ $0 (ww returned 0 where cstage returns the resolved
+ * length). cstage reads the resolved bu->alen. THE FIX: when the dim is not an
+ * N_INTLIT node, read the length from the stamped array tinfo (rule-13), in
+ * each of the local/global/def cgdot arms + letemitsize.
+ *
+ *   row     | shape                                  | exit (cs==ww)
+ *   --------+----------------------------------------+--------------
+ *   local   | def MAX=5; let buf:[MAX]u8; buf.len    | 5   (was ww 0)
+ *   global  | def MAX=5; let g:[MAX]u8;   g.len      | 5   (was ww 0)
+ *   defarr  | def MAX=5; def A:[MAX]u8;   A.len      | 5   (was ww 0)
+ *   sum     | local + global + def .len (one fn)     | 15
+ */
+#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;
+}
+
+struct row { const char *label; const char *src; int want_exit; };
+
+static const struct row rows[] = {
+	{ "local",
+	  "package main;\n"
+	  "def MAX: i32 = 5;\n"
+	  "export fn main() i32 = {\n"
+	  "	let buf: [MAX]u8 = [1, 2, 3, 4, 5];\n"
+	  "	return buf.len: i32;\n"
+	  "};\n",
+	  5 },
+
+	{ "global",
+	  "package main;\n"
+	  "def MAX: i32 = 5;\n"
+	  "let g: [MAX]u8 = [1, 2, 3, 4, 5];\n"
+	  "export fn main() i32 = {\n"
+	  "	return g.len: i32;\n"
+	  "};\n",
+	  5 },
+
+	{ "defarr",
+	  "package main;\n"
+	  "def MAX: i32 = 5;\n"
+	  "def A: [MAX]u8 = [1, 2, 3, 4, 5];\n"
+	  "export fn main() i32 = {\n"
+	  "	return A.len: i32;\n"
+	  "};\n",
+	  5 },
+
+	{ "sum",
+	  "package main;\n"
+	  "def MAX: i32 = 5;\n"
+	  "let g: [MAX]u8 = [1, 2, 3, 4, 5];\n"
+	  "def A: [MAX]u8 = [1, 2, 3, 4, 5];\n"
+	  "export fn main() i32 = {\n"
+	  "	let buf: [MAX]u8 = [1, 2, 3, 4, 5];\n"
+	  "	return (buf.len + g.len + A.len): i32;\n"
+	  "};\n",
+	  15 },
+};
+
+static int
+run_build(const char *driver, const struct row *r, int i)
+{
+	char src[64], tmpdir[64], cmd[1024];
+	snprintf(src, sizeof src, "/tmp/ddf_%d_%d.ww", getpid(), i);
+	snprintf(tmpdir, sizeof tmpdir, "/tmp/ddf_%d_d_%d", getpid(), i);
+
+	FILE *f = fopen(src, "wb");
+	if (!f) return -2;
+	fputs(r->src, f);
+	fclose(f);
+
+	mkdir(tmpdir, 0755);
+	snprintf(cmd, sizeof cmd, "cd %s && %s build %s 2>/dev/null",
+	    tmpdir, driver, src);
+	int brc = runwait(cmd);
+
+	const char *base = strrchr(src, '/');
+	base = base ? base + 1 : src;
+	char outbin[128];
+	snprintf(outbin, sizeof outbin, "%s/%s", tmpdir, base);
+	char *dot = strrchr(outbin, '.');
+	if (dot && strcmp(dot, ".ww") == 0) *dot = '\0';
+
+	int got = -1;
+	if (brc == 0) got = runwait(outbin);
+
+	unlink(src); unlink(outbin); rmdir(tmpdir);
+	return brc == 0 ? got : -1;
+}
+
+int
+main(void)
+{
+	const char *bin = getenv("BIN");
+	if (!bin) bin = "out/bin";
+	char absbin[1024];
+	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[1024], wdrv[1024];
+	snprintf(cdrv, sizeof cdrv, "%s/ww", bin);
+	snprintf(wdrv, sizeof wdrv, "%s/ww_ww", bin);
+	int have_ww = (access(wdrv, X_OK) == 0);
+
+	int n = (int)(sizeof rows / sizeof rows[0]);
+	int total = 0, fail = 0;
+
+	for (int i = 0; i < n; i++) {
+		total++;
+		int gc = run_build(cdrv, &rows[i], i);
+		if (gc < 0) {
+			fprintf(stderr, "defdim_field[cstage][%s]: build/run failed "
+			    "(got %d)\n", rows[i].label, gc);
+			fail++;
+			continue;
+		}
+		if (gc != rows[i].want_exit) {
+			fprintf(stderr, "defdim_field[cstage][%s]: exit=%d want=%d\n",
+			    rows[i].label, gc, rows[i].want_exit);
+			fail++;
+		}
+		if (!have_ww) {
+			fprintf(stderr, "defdim_field: skip wwstage (no %s)\n", wdrv);
+			continue;
+		}
+		int gw = run_build(wdrv, &rows[i], i);
+		if (gw != gc) {
+			fprintf(stderr, "defdim_field[%s]: cs=%d != ww=%d "
+			    "(def-dim .len field-read divergence — #56)\n",
+			    rows[i].label, gc, gw);
+			fail++;
+		}
+		if (gw != rows[i].want_exit) {
+			fprintf(stderr, "defdim_field[wwstage][%s]: exit=%d want=%d\n",
+			    rows[i].label, gw, rows[i].want_exit);
+			fail++;
+		}
+	}
+
+	if (fail) {
+		fprintf(stderr, "defdim_field_run: %d/%d checks failed\n",
+		    fail, total);
+		return 1;
+	}
+	printf("defdim_field_run: %d/%d ok\n", total, total);
+	return 0;
+}