selfhost: regen combined.ww for 5466ea0 strings.concat variadic

Frozen-artifact catch-up. 5466ea0 modified lib/strings/strings.ww and
lib/strings/stringstest.ww but did not regenerate the three bundled
.combined.ww files. Bisect of the frozen-fallback build path was
broken at 5466ea0..HEAD.

selfhost/cmd/w6c/main.combined.ww

@@ -1445,17 +1445,18 @@ export fn position(d: *decoder) i32 = {
 //
 // Documented divergences from Hare:
 //
-//   - `concat(a, b)` is 2-arg. Hare ships `concat(strs: str...)`
-//     (ref/hare/strings/concat.ha:5). Blocks on task #16 (cstage
-//     variadic-pack drops .len of multi-field element type). Cite
-//     reverts on fix.
 //   - `trim` / `ltrim` / `rtrim` take a single rune. Hare's are
-//     `(exclude: rune...)` (ref/hare/strings/trim.ha:54). Same
-//     blocker as concat. Hare's no-rune branch (strip whitespace)
-//     is also dropped — depends on a rune set.
+//     `(trim: rune...)` (ref/hare/strings/trim.ha:11,32,54). The
+//     port body uses `iter`/`next` + inner match against the pack +
+//     `prev` step-back; that shape triggers #36 (wwstage scanlocals
+//     misses match-arm `case let` bindings, slot offsets diverge —
+//     `.ai/probe_trim_36extra.{ww,diff}`). Hare's no-rune
+//     strip-whitespace branch additionally needs `lib/bytes`
+//     variadic graduation.
 //   - `contains` is non-variadic. Hare's is
 //     `contains(haystack, needles: (str | rune)...)`
-//     (ref/hare/strings/contains.ha:9). Same blocker.
+//     (ref/hare/strings/contains.ha:9). Gated on `(str|rune)...`
+//     tagged-variadic gather + runtime — task #5.
 //   - `byteindex` / `rbyteindex` rune arms encode via
 //     `utf8.encoderune`; the legacy impls scanned for `r: u8` (an
 //     undocumented ASCII-only restriction that silently dropped
@@ -1549,17 +1550,30 @@ export fn freeall(s: []str) void = {
 	};
 };
 
-// concat — fresh allocation containing `a` then `b`. Caller releases
-// with `os.free(r.ptr, r.len: u64)`. ref/hare/strings/concat.ha:5
-// (subset: Hare's `(strs: str...)` blocks on task #16).
-export fn concat(a: str, b: str) str = {
-	let total: i32 = a.len + b.len;
-	let buf: *u8 = os.alloc(total: u64): *u8;
+// concat — fresh allocation containing each element of `strs` in
+// order. Caller releases with `os.free(r.ptr, r.len: u64)`.
+// ref/hare/strings/concat.ha:5. Hare's `nomem` return is dropped:
+// `os.alloc` aborts on OOM.
+export fn concat(strs: str...) str = {
+	let total: i32 = 0;
 	let i: i32 = 0;
-	for (i < a.len) { buf[i] = a[i]; i += 1; };
-	let j: i32 = 0;
-	for (j < b.len) { buf[a.len + j] = b[j]; j += 1; };
+	for (i < strs.len) { total += strs[i].len; i += 1; };
 	let r: str;
+	r.ptr = nil;
+	r.len = 0;
+	if (total == 0) { return r; };
+	let buf: *u8 = os.alloc(total: u64): *u8;
+	let off: i32 = 0;
+	i = 0;
+	for (i < strs.len) {
+		let j: i32 = 0;
+		for (j < strs[i].len) {
+			buf[off + j] = strs[i][j];
+			j += 1;
+		};
+		off += strs[i].len;
+		i += 1;
+	};
 	r.ptr = buf;
 	r.len = total;
 	return r;

selfhost/cmd/wwdump/main.combined.ww

@@ -1445,17 +1445,18 @@ export fn position(d: *decoder) i32 = {
 //
 // Documented divergences from Hare:
 //
-//   - `concat(a, b)` is 2-arg. Hare ships `concat(strs: str...)`
-//     (ref/hare/strings/concat.ha:5). Blocks on task #16 (cstage
-//     variadic-pack drops .len of multi-field element type). Cite
-//     reverts on fix.
 //   - `trim` / `ltrim` / `rtrim` take a single rune. Hare's are
-//     `(exclude: rune...)` (ref/hare/strings/trim.ha:54). Same
-//     blocker as concat. Hare's no-rune branch (strip whitespace)
-//     is also dropped — depends on a rune set.
+//     `(trim: rune...)` (ref/hare/strings/trim.ha:11,32,54). The
+//     port body uses `iter`/`next` + inner match against the pack +
+//     `prev` step-back; that shape triggers #36 (wwstage scanlocals
+//     misses match-arm `case let` bindings, slot offsets diverge —
+//     `.ai/probe_trim_36extra.{ww,diff}`). Hare's no-rune
+//     strip-whitespace branch additionally needs `lib/bytes`
+//     variadic graduation.
 //   - `contains` is non-variadic. Hare's is
 //     `contains(haystack, needles: (str | rune)...)`
-//     (ref/hare/strings/contains.ha:9). Same blocker.
+//     (ref/hare/strings/contains.ha:9). Gated on `(str|rune)...`
+//     tagged-variadic gather + runtime — task #5.
 //   - `byteindex` / `rbyteindex` rune arms encode via
 //     `utf8.encoderune`; the legacy impls scanned for `r: u8` (an
 //     undocumented ASCII-only restriction that silently dropped
@@ -1549,17 +1550,30 @@ export fn freeall(s: []str) void = {
 	};
 };
 
-// concat — fresh allocation containing `a` then `b`. Caller releases
-// with `os.free(r.ptr, r.len: u64)`. ref/hare/strings/concat.ha:5
-// (subset: Hare's `(strs: str...)` blocks on task #16).
-export fn concat(a: str, b: str) str = {
-	let total: i32 = a.len + b.len;
-	let buf: *u8 = os.alloc(total: u64): *u8;
+// concat — fresh allocation containing each element of `strs` in
+// order. Caller releases with `os.free(r.ptr, r.len: u64)`.
+// ref/hare/strings/concat.ha:5. Hare's `nomem` return is dropped:
+// `os.alloc` aborts on OOM.
+export fn concat(strs: str...) str = {
+	let total: i32 = 0;
 	let i: i32 = 0;
-	for (i < a.len) { buf[i] = a[i]; i += 1; };
-	let j: i32 = 0;
-	for (j < b.len) { buf[a.len + j] = b[j]; j += 1; };
+	for (i < strs.len) { total += strs[i].len; i += 1; };
 	let r: str;
+	r.ptr = nil;
+	r.len = 0;
+	if (total == 0) { return r; };
+	let buf: *u8 = os.alloc(total: u64): *u8;
+	let off: i32 = 0;
+	i = 0;
+	for (i < strs.len) {
+		let j: i32 = 0;
+		for (j < strs[i].len) {
+			buf[off + j] = strs[i][j];
+			j += 1;
+		};
+		off += strs[i].len;
+		i += 1;
+	};
 	r.ptr = buf;
 	r.len = total;
 	return r;

selfhost/test/smoke.combined.ww

@@ -1336,17 +1336,18 @@ export fn position(d: *decoder) i32 = {
 //
 // Documented divergences from Hare:
 //
-//   - `concat(a, b)` is 2-arg. Hare ships `concat(strs: str...)`
-//     (ref/hare/strings/concat.ha:5). Blocks on task #16 (cstage
-//     variadic-pack drops .len of multi-field element type). Cite
-//     reverts on fix.
 //   - `trim` / `ltrim` / `rtrim` take a single rune. Hare's are
-//     `(exclude: rune...)` (ref/hare/strings/trim.ha:54). Same
-//     blocker as concat. Hare's no-rune branch (strip whitespace)
-//     is also dropped — depends on a rune set.
+//     `(trim: rune...)` (ref/hare/strings/trim.ha:11,32,54). The
+//     port body uses `iter`/`next` + inner match against the pack +
+//     `prev` step-back; that shape triggers #36 (wwstage scanlocals
+//     misses match-arm `case let` bindings, slot offsets diverge —
+//     `.ai/probe_trim_36extra.{ww,diff}`). Hare's no-rune
+//     strip-whitespace branch additionally needs `lib/bytes`
+//     variadic graduation.
 //   - `contains` is non-variadic. Hare's is
 //     `contains(haystack, needles: (str | rune)...)`
-//     (ref/hare/strings/contains.ha:9). Same blocker.
+//     (ref/hare/strings/contains.ha:9). Gated on `(str|rune)...`
+//     tagged-variadic gather + runtime — task #5.
 //   - `byteindex` / `rbyteindex` rune arms encode via
 //     `utf8.encoderune`; the legacy impls scanned for `r: u8` (an
 //     undocumented ASCII-only restriction that silently dropped
@@ -1440,17 +1441,30 @@ export fn freeall(s: []str) void = {
 	};
 };
 
-// concat — fresh allocation containing `a` then `b`. Caller releases
-// with `os.free(r.ptr, r.len: u64)`. ref/hare/strings/concat.ha:5
-// (subset: Hare's `(strs: str...)` blocks on task #16).
-export fn concat(a: str, b: str) str = {
-	let total: i32 = a.len + b.len;
-	let buf: *u8 = os.alloc(total: u64): *u8;
+// concat — fresh allocation containing each element of `strs` in
+// order. Caller releases with `os.free(r.ptr, r.len: u64)`.
+// ref/hare/strings/concat.ha:5. Hare's `nomem` return is dropped:
+// `os.alloc` aborts on OOM.
+export fn concat(strs: str...) str = {
+	let total: i32 = 0;
 	let i: i32 = 0;
-	for (i < a.len) { buf[i] = a[i]; i += 1; };
-	let j: i32 = 0;
-	for (j < b.len) { buf[a.len + j] = b[j]; j += 1; };
+	for (i < strs.len) { total += strs[i].len; i += 1; };
 	let r: str;
+	r.ptr = nil;
+	r.len = 0;
+	if (total == 0) { return r; };
+	let buf: *u8 = os.alloc(total: u64): *u8;
+	let off: i32 = 0;
+	i = 0;
+	for (i < strs.len) {
+		let j: i32 = 0;
+		for (j < strs[i].len) {
+			buf[off + j] = strs[i][j];
+			j += 1;
+		};
+		off += strs[i].len;
+		i += 1;
+	};
 	r.ptr = buf;
 	r.len = total;
 	return r;