wcc/ww: def-dim array slice-arg default-hi takes the length from the type table

Passing buf[1:] of a [MAX]u8 as a call arg dropped the default-hi
length (the arg-push N_SLICE arms' fallback covered only named-alias
bases). Same type-table resolve at pushargsrev local+global. This
closes the def-dim dimension family by construction: every N_INTLIT-
keyed dim consumer (cgslice, cgdot, letemitsize, arg-push) now
carries the tichase().alen fallback — grep-proven, no consumer
remains. Fourth member surfaced by the family grep.

Makefile

@@ -258,6 +258,7 @@ TESTS	= $(BIN)/test_smoke $(BIN)/test_lex $(BIN)/test_parse $(BIN)/test_check \
 	  $(BIN)/test_trystr_run \
 	  $(BIN)/test_allocalias_run \
 	  $(BIN)/test_defdim_field_run \
+	  $(BIN)/test_defdim_argslice_run \
 	  $(BIN)/test_gunsigned_run \
 	  $(BIN)/test_taggedidx_run \
 	  $(BIN)/test_fnptrcollide_run \
@@ -769,6 +770,17 @@ $(BIN)/test_defdim_field_run: test/wcc/989_defdim_field_run.c \
 		$(LIB)/libwwrt.a | $(BIN)
 	$(CC) $(CFLAGS) -o $@ $<
 
+# 989_defdim_argslice_run (#56 c4): passing a slice of a `def`-dimensioned
+# array as a call arg resolves the default-hi length from the type table in
+# the N_SLICE arg-push arms (cgenutil pushargsrev local+global). Builds+runs
+# on BOTH driver twins (rule-10).
+$(BIN)/test_defdim_argslice_run: test/wcc/989_defdim_argslice_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

@@ -18355,10 +18355,21 @@ fn pushargsrev(c: *cgen, arg: *node, param: *node, memphase: bool) i32 = {
 			if (tn != nil) {
 				if (tn.kind == nkind.N_TARRAY) {
 					let lenn: *node = tn.rhs;
-					if (lenn != nil) {
-						if (lenn.kind == nkind.N_INTLIT) {
+					if (lenn != nil && lenn.kind == nkind.N_INTLIT) {
+						emitline("\tMOVQ\t$");
+						emituint(lenn.uval);
+						emitline(", AX\n");
+					} else {
+						// #56: def/const dim — resolve from the stamped
+						// array tinfo (rule-13). The #60 bu60 arm below
+						// covers only NAMED-alias bases (tn.kind ==
+						// N_TNAME); a plain `[MAX]u8` base reaches here
+						// with a non-N_INTLIT dim and dropped the
+						// default-hi entirely. cstage reads bu->alen.
+						let abt: *tinfo = tichase(tn.type_: *tinfo);
+						if (abt != nil && abt.kind == tykind.TY_ARRAY) {
 							emitline("\tMOVQ\t$");
-							emituint(lenn.uval);
+							emitint(abt.alen: i64);
 							emitline(", AX\n");
 						};
 					};
@@ -18391,10 +18402,18 @@ fn pushargsrev(c: *cgen, arg: *node, param: *node, memphase: bool) i32 = {
 		} else { if (globaltn != nil) {
 			if (globaltn.kind == nkind.N_TARRAY) {
 				let lenn: *node = globaltn.rhs;
-				if (lenn != nil) {
-					if (lenn.kind == nkind.N_INTLIT) {
+				if (lenn != nil && lenn.kind == nkind.N_INTLIT) {
+					emitline("\tMOVQ\t$");
+					emituint(lenn.uval);
+					emitline(", AX\n");
+				} else {
+					// #56: def/const dim on a global array base —
+					// resolve from the stamped array tinfo (rule-13),
+					// twin of the local arg-push arm above.
+					let abt: *tinfo = tichase(globaltn.type_: *tinfo);
+					if (abt != nil && abt.kind == tykind.TY_ARRAY) {
 						emitline("\tMOVQ\t$");
-						emituint(lenn.uval);
+						emitint(abt.alen: i64);
 						emitline(", AX\n");
 					};
 				};

selfhost/cmd/wcc/cgenutil.ww

@@ -641,10 +641,21 @@ fn pushargsrev(c: *cgen, arg: *node, param: *node, memphase: bool) i32 = {
 			if (tn != nil) {
 				if (tn.kind == nkind.N_TARRAY) {
 					let lenn: *node = tn.rhs;
-					if (lenn != nil) {
-						if (lenn.kind == nkind.N_INTLIT) {
+					if (lenn != nil && lenn.kind == nkind.N_INTLIT) {
+						emitline("\tMOVQ\t$");
+						emituint(lenn.uval);
+						emitline(", AX\n");
+					} else {
+						// #56: def/const dim — resolve from the stamped
+						// array tinfo (rule-13). The #60 bu60 arm below
+						// covers only NAMED-alias bases (tn.kind ==
+						// N_TNAME); a plain `[MAX]u8` base reaches here
+						// with a non-N_INTLIT dim and dropped the
+						// default-hi entirely. cstage reads bu->alen.
+						let abt: *tinfo = tichase(tn.type_: *tinfo);
+						if (abt != nil && abt.kind == tykind.TY_ARRAY) {
 							emitline("\tMOVQ\t$");
-							emituint(lenn.uval);
+							emitint(abt.alen: i64);
 							emitline(", AX\n");
 						};
 					};
@@ -677,10 +688,18 @@ fn pushargsrev(c: *cgen, arg: *node, param: *node, memphase: bool) i32 = {
 		} else { if (globaltn != nil) {
 			if (globaltn.kind == nkind.N_TARRAY) {
 				let lenn: *node = globaltn.rhs;
-				if (lenn != nil) {
-					if (lenn.kind == nkind.N_INTLIT) {
+				if (lenn != nil && lenn.kind == nkind.N_INTLIT) {
+					emitline("\tMOVQ\t$");
+					emituint(lenn.uval);
+					emitline(", AX\n");
+				} else {
+					// #56: def/const dim on a global array base —
+					// resolve from the stamped array tinfo (rule-13),
+					// twin of the local arg-push arm above.
+					let abt: *tinfo = tichase(globaltn.type_: *tinfo);
+					if (abt != nil && abt.kind == tykind.TY_ARRAY) {
 						emitline("\tMOVQ\t$");
-						emituint(lenn.uval);
+						emitint(abt.alen: i64);
 						emitline(", AX\n");
 					};
 				};

selfhost/cmd/wwdump/main.combined.ww

@@ -18355,10 +18355,21 @@ fn pushargsrev(c: *cgen, arg: *node, param: *node, memphase: bool) i32 = {
 			if (tn != nil) {
 				if (tn.kind == nkind.N_TARRAY) {
 					let lenn: *node = tn.rhs;
-					if (lenn != nil) {
-						if (lenn.kind == nkind.N_INTLIT) {
+					if (lenn != nil && lenn.kind == nkind.N_INTLIT) {
+						emitline("\tMOVQ\t$");
+						emituint(lenn.uval);
+						emitline(", AX\n");
+					} else {
+						// #56: def/const dim — resolve from the stamped
+						// array tinfo (rule-13). The #60 bu60 arm below
+						// covers only NAMED-alias bases (tn.kind ==
+						// N_TNAME); a plain `[MAX]u8` base reaches here
+						// with a non-N_INTLIT dim and dropped the
+						// default-hi entirely. cstage reads bu->alen.
+						let abt: *tinfo = tichase(tn.type_: *tinfo);
+						if (abt != nil && abt.kind == tykind.TY_ARRAY) {
 							emitline("\tMOVQ\t$");
-							emituint(lenn.uval);
+							emitint(abt.alen: i64);
 							emitline(", AX\n");
 						};
 					};
@@ -18391,10 +18402,18 @@ fn pushargsrev(c: *cgen, arg: *node, param: *node, memphase: bool) i32 = {
 		} else { if (globaltn != nil) {
 			if (globaltn.kind == nkind.N_TARRAY) {
 				let lenn: *node = globaltn.rhs;
-				if (lenn != nil) {
-					if (lenn.kind == nkind.N_INTLIT) {
+				if (lenn != nil && lenn.kind == nkind.N_INTLIT) {
+					emitline("\tMOVQ\t$");
+					emituint(lenn.uval);
+					emitline(", AX\n");
+				} else {
+					// #56: def/const dim on a global array base —
+					// resolve from the stamped array tinfo (rule-13),
+					// twin of the local arg-push arm above.
+					let abt: *tinfo = tichase(globaltn.type_: *tinfo);
+					if (abt != nil && abt.kind == tykind.TY_ARRAY) {
 						emitline("\tMOVQ\t$");
-						emituint(lenn.uval);
+						emitint(abt.alen: i64);
 						emitline(", AX\n");
 					};
 				};

test/wcc/989_defdim_argslice_run.c

@@ -0,0 +1,165 @@
+/*
+ * 989_defdim_argslice_run (#56, c4) — passing a slice of a `def`-dimensioned
+ * array (`take(buf[1:])` on `[MAX]T`) as a call argument must resolve the
+ * default-hi length from the type table, the N_SLICE arg-push member of the
+ * def-dim family.
+ *
+ * THE BUG (wwstage only): pushargsrev's N_SLICE default-hi arms (cgenutil.ww
+ * local ~643 / global ~690) read the array dimension straight off the AST
+ * tnode and only handled an N_INTLIT dim. The #60 bu60 fallback fires ONLY for
+ * NAMED-alias bases (bt60.kind == TY_NAMED), so a PLAIN `[MAX]u8` base reached
+ * the N_INTLIT arm, emitted nothing, and the slice header's len word was left
+ * stale — the callee read garbage. cstage reads the resolved bu->alen. THE
+ * FIX: when the dim is not N_INTLIT, read alen from the stamped array tinfo
+ * (rule-13), in both the local and global arg-push arms — the same shape as
+ * the #21 cgslice and #56 cgdot fixes.
+ *
+ *   row     | shape                                      | exit (cs==ww)
+ *   --------+--------------------------------------------+--------------
+ *   local   | def MAX=5; let buf:[MAX]u8; take(buf[1:])  | 4   (was ww 135)
+ *   global  | def MAX=5; let g:[MAX]u8;   take(g[1:])    | 4   (was ww 255)
+ *   litctrl | let buf:[5]u8;             take(buf[1:])   | 4   (no regress)
+ * The litctrl row pins the literal-dim path so the new else-arm can't double-
+ * emit or perturb it.
+ */
+#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"
+	  "fn take(s: []u8) i32 = { return s.len: i32; };\n"
+	  "export fn main() i32 = {\n"
+	  "	let buf: [MAX]u8 = [1, 2, 3, 4, 5];\n"
+	  "	return take(buf[1:]);\n"
+	  "};\n",
+	  4 },
+
+	{ "global",
+	  "package main;\n"
+	  "def MAX: i32 = 5;\n"
+	  "let g: [MAX]u8 = [1, 2, 3, 4, 5];\n"
+	  "fn take(s: []u8) i32 = { return s.len: i32; };\n"
+	  "export fn main() i32 = {\n"
+	  "	return take(g[1:]);\n"
+	  "};\n",
+	  4 },
+
+	{ "litctrl",
+	  "package main;\n"
+	  "fn take(s: []u8) i32 = { return s.len: i32; };\n"
+	  "export fn main() i32 = {\n"
+	  "	let buf: [5]u8 = [1, 2, 3, 4, 5];\n"
+	  "	return take(buf[1:]);\n"
+	  "};\n",
+	  4 },
+};
+
+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/dda_%d_%d.ww", getpid(), i);
+	snprintf(tmpdir, sizeof tmpdir, "/tmp/dda_%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_argslice[cstage][%s]: build/run failed "
+			    "(got %d)\n", rows[i].label, gc);
+			fail++;
+			continue;
+		}
+		if (gc != rows[i].want_exit) {
+			fprintf(stderr, "defdim_argslice[cstage][%s]: exit=%d want=%d\n",
+			    rows[i].label, gc, rows[i].want_exit);
+			fail++;
+		}
+		if (!have_ww) {
+			fprintf(stderr, "defdim_argslice: skip wwstage (no %s)\n", wdrv);
+			continue;
+		}
+		int gw = run_build(wdrv, &rows[i], i);
+		if (gw != gc) {
+			fprintf(stderr, "defdim_argslice[%s]: cs=%d != ww=%d "
+			    "(def-dim arg-push default-hi divergence — #56 c4)\n",
+			    rows[i].label, gc, gw);
+			fail++;
+		}
+		if (gw != rows[i].want_exit) {
+			fprintf(stderr, "defdim_argslice[wwstage][%s]: exit=%d want=%d\n",
+			    rows[i].label, gw, rows[i].want_exit);
+			fail++;
+		}
+	}
+
+	if (fail) {
+		fprintf(stderr, "defdim_argslice_run: %d/%d checks failed\n",
+		    fail, total);
+		return 1;
+	}
+	printf("defdim_argslice_run: %d/%d ok\n", total, total);
+	return 0;
+}