ww: cgen trap batch (def-str field, chained-ptr write, scalar+str tuple ABI)

test/wcc/700_e2e.c

@@ -806,6 +806,69 @@ static const struct row rows[] = {
 	  "  };\n"
 	  "  return acc;\n"
 	  "};", 16 },	/* 3 + 3 + len(\"no newline\")=10 */
+	/* `(scalar, str)` tuple return: AX:DX:CX convention extends the
+	 * tagged-union ABI. AX = scalar, DX = str.ptr, CX = str.len.
+	 * Receive sites destructure off the same regs regardless of
+	 * positional order. Without the fix, len was lost (only AX:DX
+	 * returned), every receive shape gave garbage. */
+	{ "fn split() (i64, str) = { return 42, \"hello\"; };\n"
+	  "fn main() i32 = {\n"
+	  "  let n, s = split();\n"
+	  "  return (n: i32) + (s.len: i32);\n"
+	  "};", 47 },
+	{ "fn split() (str, i64) = { return \"hello\", 42; };\n"
+	  "fn main() i32 = {\n"
+	  "  let s, n = split();\n"
+	  "  return (n: i32) + (s.len: i32);\n"
+	  "};", 47 },
+	{ "fn split() (i64, str) = { return 42, \"hello\"; };\n"
+	  "fn main() i32 = {\n"
+	  "  let t: (i64, str) = split();\n"
+	  "  return (t.0: i32) + (t.1.len: i32);\n"
+	  "};", 47 },
+	/* Hare-style paren tuple-destructure with str element */
+	{ "fn split() (i64, str) = { return 42, \"hello\"; };\n"
+	  "fn main() i32 = {\n"
+	  "  let (n, s) = split();\n"
+	  "  return (n: i32) + (s.len: i32);\n"
+	  "};", 47 },
+	/* Chained field write through a pointer field: `r.sym.flag = v`
+	 * where `r.sym: *T`. The cgen must evaluate the inner pointer,
+	 * then store at *(ptr + field.offset). Without the fix, the
+	 * single-level N_IDENT-base path doesn't fire (base is itself
+	 * an N_DOT) and the assignment silently emits no instructions.
+	 * Compound op + 1-byte field + 3-level chain all exercised. */
+	{ "type inner = struct { tag: u8, pad: u8, flag: i32 };\n"
+	  "type outer = struct { sym: *inner };\n"
+	  "fn main() i32 = {\n"
+	  "  let i: inner = inner { tag = 0u8, pad = 0u8, flag = 10 };\n"
+	  "  let r: outer = outer { sym = &i };\n"
+	  "  r.sym.flag += 32;\n"
+	  "  r.sym.tag = 5u8;\n"
+	  "  return r.sym.flag + (r.sym.tag: i32);\n"
+	  "};", 47 },
+	{ "type leaf = struct { v: i32 };\n"
+	  "type mid  = struct { l: *leaf };\n"
+	  "type top  = struct { m: *mid };\n"
+	  "fn main() i32 = {\n"
+	  "  let lf: leaf = leaf { v = 0 };\n"
+	  "  let md: mid  = mid  { l = &lf };\n"
+	  "  let tp: top  = top  { m = &md };\n"
+	  "  tp.m.l.v = 99;\n"
+	  "  return tp.m.l.v;\n"
+	  "};", 99 },
+	/* `def NAME: str = \"lit\"` field access. The Sdef has no stack
+	 * slot, so .len/.ptr must inline the literal length / strlit
+	 * address; without the fix, .len reads BP+8 (return-address slot)
+	 * as garbage. */
+	{ "def MSG: str = \"hello world\";\n"
+	  "fn main() i32 = { return MSG.len: i32; };", 11 },
+	{ "use os;\n"
+	  "def GREETING: str = \"hi\\n\";\n"
+	  "fn main() i32 = {\n"
+	  "  os.write(1, GREETING.ptr, GREETING.len: u64);\n"
+	  "  return GREETING.len: i32;\n"
+	  "};", 3 },
 	{ NULL, 0 }
 };