diff --git a/Makefile b/Makefile
index af136c94..d2d16ee2 100644
--- a/Makefile
+++ b/Makefile
@@ -322,6 +322,7 @@ TESTS	= $(BIN)/test_smoke $(BIN)/test_lex $(BIN)/test_parse $(BIN)/test_check \
 	  $(BIN)/test_dot_aliased_ptr \
 	  $(BIN)/test_return_tagged_forward \
 	  $(BIN)/test_widen_transitive \
+	  $(BIN)/test_typeassert_nonident \
 	  $(BIN)/test_use_promote_alias \
 	  $(BIN)/test_field_signed $(BIN)/test_frame_argcount \
 	  $(BIN)/test_selfhost $(BIN)/test_w6a_ww $(BIN)/test_w6l_ww \
@@ -660,6 +661,12 @@ $(BIN)/test_widen_transitive: test/wcc/771_widen_transitive.c \
 		$(LIB)/libwwrt.a | $(BIN)
 	$(CC) $(CFLAGS) -o $@ $<
 
+$(BIN)/test_typeassert_nonident: test/wcc/772_typeassert_nonident.c \
+		$(BIN)/ww $(BIN)/w6c $(BIN)/w6a $(BIN)/w6l \
+		$(BIN)/ww_ww $(BIN)/w6c_ww $(BIN)/w6a_ww $(BIN)/w6l_ww \
+		$(LIB)/libwwrt.a | $(BIN)
+	$(CC) $(CFLAGS) -o $@ $<
+
 $(BIN)/test_arrlit_str_full: test/wcc/711_arrlit_str_full.c \
 		$(BIN)/ww $(BIN)/w6c $(BIN)/w6a $(BIN)/w6l \
 		$(BIN)/ww_ww $(BIN)/w6c_ww $(BIN)/w6a_ww $(BIN)/w6l_ww \
diff --git a/selfhost/cmd/w6c/main.combined.ww b/selfhost/cmd/w6c/main.combined.ww
index 95165821..c728aa78 100644
--- a/selfhost/cmd/w6c/main.combined.ww
+++ b/selfhost/cmd/w6c/main.combined.ww
@@ -18010,6 +18010,41 @@ fn cgtypeassert(c: *cgen, n: *node) void = {
 				scrutoff = lc.off;
 				scrutt = resolvetagged(c, lc.tnode);
 			};
+		} else {
+			// Non-ident scrutinee (call result, arr[i], p.field, ?,
+			// etc.). Mirror cgmatch's spill (cgenexpr.ww:1422-1460)
+			// and cstage cmd/w6c/cgen.c:6300-6316: alloc an
+			// `@asrt_spill` slot sized via matchspillsz, evaluate
+			// the LHS, then copy the AX/DX/CX[/R8] return-ABI words
+			// into the slot so the tag-check + payload load indexes
+			// off memory like the IDENT path. Without this, scrutoff
+			// stayed 0 and the tag read fell on (BP) — the saved-BP
+			// word — and the payload read on +8(BP) — the return
+			// address. Bug #200.
+			scrutt = matchscrutt(c, lhs);
+			let spillsz: i32 = matchspillsz(c, scrutt);
+			scrutoff = localalloc(c, "@asrt_spill", spillsz, nil);
+			cgexpr(c, lhs);
+			emitline("\tMOVQ\tAX, ");
+			emitoff(scrutoff: i64);
+			emitline("(BP)\n");
+			if (!isnullabletype(scrutt)) {
+				emitline("\tMOVQ\tDX, ");
+				emitoff((scrutoff + 8): i64);
+				emitline("(BP)\n");
+				// Mirror cstage cmd/w6c/cgen.c:6313-6315: only CX
+				// → +16 when slot_size > 16. The 4-word case
+				// (R8 → +24, slot_size > 24) is the cgmatch shape
+				// (cgenexpr.ww:1454-1458, cmd/w6c/cgen.c:5988-5990)
+				// but cstage cgtypeassert omits it; preserve the
+				// asymmetry rather than diverge from rule 10
+				// byte-id. Filed inline as a cstage twin task.
+				if (spillsz > 16) {
+					emitline("\tMOVQ\tCX, ");
+					emitoff((scrutoff + 16): i64);
+					emitline("(BP)\n");
+				};
+			};
 		};
 	};
 	let want: i32 = cgtagvariantidx(c, scrutt, n.rhs);
diff --git a/selfhost/cmd/wcc/cgenexpr.ww b/selfhost/cmd/wcc/cgenexpr.ww
index 1d2b8433..d9ac1f9f 100644
--- a/selfhost/cmd/wcc/cgenexpr.ww
+++ b/selfhost/cmd/wcc/cgenexpr.ww
@@ -387,6 +387,41 @@ fn cgtypeassert(c: *cgen, n: *node) void = {
 				scrutoff = lc.off;
 				scrutt = resolvetagged(c, lc.tnode);
 			};
+		} else {
+			// Non-ident scrutinee (call result, arr[i], p.field, ?,
+			// etc.). Mirror cgmatch's spill (cgenexpr.ww:1422-1460)
+			// and cstage cmd/w6c/cgen.c:6300-6316: alloc an
+			// `@asrt_spill` slot sized via matchspillsz, evaluate
+			// the LHS, then copy the AX/DX/CX[/R8] return-ABI words
+			// into the slot so the tag-check + payload load indexes
+			// off memory like the IDENT path. Without this, scrutoff
+			// stayed 0 and the tag read fell on (BP) — the saved-BP
+			// word — and the payload read on +8(BP) — the return
+			// address. Bug #200.
+			scrutt = matchscrutt(c, lhs);
+			let spillsz: i32 = matchspillsz(c, scrutt);
+			scrutoff = localalloc(c, "@asrt_spill", spillsz, nil);
+			cgexpr(c, lhs);
+			emitline("\tMOVQ\tAX, ");
+			emitoff(scrutoff: i64);
+			emitline("(BP)\n");
+			if (!isnullabletype(scrutt)) {
+				emitline("\tMOVQ\tDX, ");
+				emitoff((scrutoff + 8): i64);
+				emitline("(BP)\n");
+				// Mirror cstage cmd/w6c/cgen.c:6313-6315: only CX
+				// → +16 when slot_size > 16. The 4-word case
+				// (R8 → +24, slot_size > 24) is the cgmatch shape
+				// (cgenexpr.ww:1454-1458, cmd/w6c/cgen.c:5988-5990)
+				// but cstage cgtypeassert omits it; preserve the
+				// asymmetry rather than diverge from rule 10
+				// byte-id. Filed inline as a cstage twin task.
+				if (spillsz > 16) {
+					emitline("\tMOVQ\tCX, ");
+					emitoff((scrutoff + 16): i64);
+					emitline("(BP)\n");
+				};
+			};
 		};
 	};
 	let want: i32 = cgtagvariantidx(c, scrutt, n.rhs);
diff --git a/selfhost/cmd/wwdump/main.combined.ww b/selfhost/cmd/wwdump/main.combined.ww
index 785fb0a4..0b6a2fd9 100644
--- a/selfhost/cmd/wwdump/main.combined.ww
+++ b/selfhost/cmd/wwdump/main.combined.ww
@@ -18010,6 +18010,41 @@ fn cgtypeassert(c: *cgen, n: *node) void = {
 				scrutoff = lc.off;
 				scrutt = resolvetagged(c, lc.tnode);
 			};
+		} else {
+			// Non-ident scrutinee (call result, arr[i], p.field, ?,
+			// etc.). Mirror cgmatch's spill (cgenexpr.ww:1422-1460)
+			// and cstage cmd/w6c/cgen.c:6300-6316: alloc an
+			// `@asrt_spill` slot sized via matchspillsz, evaluate
+			// the LHS, then copy the AX/DX/CX[/R8] return-ABI words
+			// into the slot so the tag-check + payload load indexes
+			// off memory like the IDENT path. Without this, scrutoff
+			// stayed 0 and the tag read fell on (BP) — the saved-BP
+			// word — and the payload read on +8(BP) — the return
+			// address. Bug #200.
+			scrutt = matchscrutt(c, lhs);
+			let spillsz: i32 = matchspillsz(c, scrutt);
+			scrutoff = localalloc(c, "@asrt_spill", spillsz, nil);
+			cgexpr(c, lhs);
+			emitline("\tMOVQ\tAX, ");
+			emitoff(scrutoff: i64);
+			emitline("(BP)\n");
+			if (!isnullabletype(scrutt)) {
+				emitline("\tMOVQ\tDX, ");
+				emitoff((scrutoff + 8): i64);
+				emitline("(BP)\n");
+				// Mirror cstage cmd/w6c/cgen.c:6313-6315: only CX
+				// → +16 when slot_size > 16. The 4-word case
+				// (R8 → +24, slot_size > 24) is the cgmatch shape
+				// (cgenexpr.ww:1454-1458, cmd/w6c/cgen.c:5988-5990)
+				// but cstage cgtypeassert omits it; preserve the
+				// asymmetry rather than diverge from rule 10
+				// byte-id. Filed inline as a cstage twin task.
+				if (spillsz > 16) {
+					emitline("\tMOVQ\tCX, ");
+					emitoff((scrutoff + 16): i64);
+					emitline("(BP)\n");
+				};
+			};
 		};
 	};
 	let want: i32 = cgtagvariantidx(c, scrutt, n.rhs);
diff --git a/test/wcc/772_typeassert_nonident.c b/test/wcc/772_typeassert_nonident.c
new file mode 100644
index 00000000..2f07505c
--- /dev/null
+++ b/test/wcc/772_typeassert_nonident.c
@@ -0,0 +1,332 @@
+/*
+ * 772_typeassert_nonident — project #200: wwstage cgtypeassert non-IDENT
+ * scrutinee bug. The pre-fix `e as T` on a non-N_IDENT scrutinee (direct
+ * call result, arr[i], p.field, ?, paren-wrap of any of those) left
+ * scrutoff=0; the tag-load fell on (BP) — the saved-BP word — and the
+ * payload-load on +8(BP) — the return address — instead of the spilled
+ * tagged-return ABI words. wwstage produced garbage (exit 220 in the
+ * repro vs cstage's 42).
+ *
+ * Fix (selfhost/cmd/wcc/cgenexpr.ww:368-414 cgtypeassert): mirror cstage
+ * cmd/w6c/cgen.c:6300-6316 N_TYPEASSERT non-IDENT arm. Add an `else`
+ * branch after the existing N_IDENT path: resolve the tagged type via
+ * matchscrutt, alloc an `@asrt_spill` slot via matchspillsz/localalloc,
+ * cgexpr the LHS, then spill AX→+0 (tag), DX→+8 (word0), CX→+16
+ * (word1) guarded on spill > 16. Mirrors cgmatch's spill (cgenexpr.ww:
+ * 1422-1460). The R8→+24 path (cgmatch shape) is intentionally omitted
+ * to mirror cstage's cgtypeassert exactly (rule-10 byte-id); the cstage
+ * twin gap is filed inline as a sibling task.
+ *
+ * Coverage (7 rows):
+ *   1. call_as_size       — `f() as size`. The repro shape: direct call
+ *                            result, basic-size payload. Pre-fix
+ *                            wwstage: garbage AX from (BP). Post-fix:
+ *                            42.
+ *   2. call_as_str        — `f() as str`. Non-IDENT, multi-word payload
+ *                            (AX=ptr / BX=len). Tests CX→+16 spill +
+ *                            the `isstrtype` post-spill BX load.
+ *   3. call_as_namedvoid  — `f() as nvariant` where nvariant is a
+ *                            named-void alias. Tag-check fires; the
+ *                            payload load is a 0-byte no-op (void
+ *                            variant has size 0; no consumer reads AX).
+ *                            Drew-add.
+ *   4. call_as_fnptr      — `f() as *fn(i32) i32`. Fn-ptr variant
+ *                            (8B word0 = pointer). Round-trips through
+ *                            spill→tag-check→MOVQ +8 → AX.
+ *   5. call_as_u8         — `f() as u8`. Narrow scalar. The callee
+ *                            zero/sign-extended the value to 8B on
+ *                            return; MOVQ store + MOVQ read round-trips
+ *                            it. Ken-add: confirms no narrow-truncation
+ *                            on the payload load.
+ *   6. call_as_i16        — `f() as i16`. Narrow signed scalar. Tests
+ *                            negative round-trip through the spill slot
+ *                            (callee sign-extended to 8B; MOVQ
+ *                            preserves). Ken-add sibling of row 5.
+ *   7. branched_call_as   — callee returns a runtime-chosen variant
+ *                            (the success branch); `f(true) as size`.
+ *                            Tests that the spill+tag-check path
+ *                            doesn't lose the callee's selected tag.
+ *
+ * Per-row gates: cstage runtime exit, wwstage runtime exit, cs.s ==
+ * ww.s byte-identical (rule-10 stage symmetry).
+ *
+ * GATE POLARITY: must stay GREEN. A red on rows 1-4 or 7 means the
+ * spill path is broken (non-IDENT scrutinee returned to the BP/RIP
+ * read). Rows 5/6 red means narrow-scalar round-trip miscompiled at
+ * the payload load (would surface if a future SIB regresses MOVQ to a
+ * narrow load that drops the callee's extension).
+ */
+#include <stdio.h>
+#include <stdlib.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;
+}
+
+#define STAGE_CS	1
+#define STAGE_WW	2
+
+struct row {
+	const char *label;
+	const char *src;
+	int expected_exit;
+	int stage_mask;
+};
+
+static const struct row rows[] = {
+	{ "call_as_size",
+	  "package main;\n"
+	  "fn f(b: bool) (size | str) = {\n"
+	  "    if (b) { return 42: size; };\n"
+	  "    return \"x\";\n"
+	  "};\n"
+	  "export fn main() i32 = {\n"
+	  "    let n = f(true) as size;\n"
+	  "    return n: i32;\n"
+	  "};\n",
+	  42,
+	  STAGE_CS | STAGE_WW },
+	{ "call_as_str",
+	  "package main;\n"
+	  "fn f(b: bool) (size | str) = {\n"
+	  "    if (b) { return \"AB\"; };\n"
+	  "    return 0: size;\n"
+	  "};\n"
+	  "export fn main() i32 = {\n"
+	  "    let s = f(true) as str;\n"
+	  "    return s.len: i32 + 40;\n"
+	  "};\n",
+	  42,
+	  STAGE_CS | STAGE_WW },
+	{ "call_as_namedvoid",
+	  "package main;\n"
+	  "type nv = void;\n"
+	  "fn f(b: bool) (size | nv) = {\n"
+	  "    if (b) { return void: nv; };\n"
+	  "    return 0: size;\n"
+	  "};\n"
+	  "export fn main() i32 = {\n"
+	  "    let _ = f(true) as nv;\n"
+	  "    return 42;\n"
+	  "};\n",
+	  42,
+	  STAGE_CS | STAGE_WW },
+	{ "call_as_fnptr",
+	  /* #193: explicit deref required to call a fn-ptr (`(*p)(args)`).
+	   * The probe is wwstage cgtypeassert non-IDENT spill; deref-call
+	   * shape is orthogonal. */
+	  "package main;\n"
+	  "fn g(x: i32) i32 = { return x + 1; };\n"
+	  "fn f(b: bool) (*fn(x: i32) i32 | size) = {\n"
+	  "    if (b) { return &g; };\n"
+	  "    return 0: size;\n"
+	  "};\n"
+	  "export fn main() i32 = {\n"
+	  "    let p = f(true) as *fn(x: i32) i32;\n"
+	  "    return (*p)(41);\n"
+	  "};\n",
+	  42,
+	  STAGE_CS | STAGE_WW },
+	{ "call_as_u8",
+	  "package main;\n"
+	  "fn f(b: bool) (u8 | str) = {\n"
+	  "    if (b) { return 42: u8; };\n"
+	  "    return \"x\";\n"
+	  "};\n"
+	  "export fn main() i32 = {\n"
+	  "    let n = f(true) as u8;\n"
+	  "    return n: i32;\n"
+	  "};\n",
+	  42,
+	  STAGE_CS | STAGE_WW },
+	{ "call_as_i16",
+	  "package main;\n"
+	  "fn f(b: bool) (i16 | str) = {\n"
+	  "    if (b) { return -1: i16; };\n"
+	  "    return \"x\";\n"
+	  "};\n"
+	  "export fn main() i32 = {\n"
+	  "    let n = f(true) as i16;\n"
+	  "    if (n: i32 == -1) { return 42; };\n"
+	  "    return 1;\n"
+	  "};\n",
+	  42,
+	  STAGE_CS | STAGE_WW },
+	{ "branched_call_as",
+	  "package main;\n"
+	  "fn f(b: bool) (size | str) = {\n"
+	  "    if (b) { return 42: size; };\n"
+	  "    return \"x\";\n"
+	  "};\n"
+	  "export fn main() i32 = {\n"
+	  "    let pick: bool = true;\n"
+	  "    let n = f(pick) as size;\n"
+	  "    return n: i32;\n"
+	  "};\n",
+	  42,
+	  STAGE_CS | STAGE_WW },
+};
+
+static int
+write_source(const char *path, const char *src)
+{
+	FILE *f = fopen(path, "wb");
+	if (!f) return -1;
+	fputs(src, f);
+	fclose(f);
+	return 0;
+}
+
+static void
+cleanup_tmp(const char *tmpdir, const char *base)
+{
+	char p[512];
+	snprintf(p, sizeof p, "%s/%s.ww", tmpdir, base); unlink(p);
+	snprintf(p, sizeof p, "%s/%s.s",  tmpdir, base); unlink(p);
+	snprintf(p, sizeof p, "%s/%s.o",  tmpdir, base); unlink(p);
+	snprintf(p, sizeof p, "%s/%s.combined.ww", tmpdir, base); unlink(p);
+	snprintf(p, sizeof p, "%s/%s",    tmpdir, base); unlink(p);
+	rmdir(tmpdir);
+}
+
+static int
+build_via_driver(const char *driver, const char *tmpdir, const char *src)
+{
+	char cmd[1024];
+	snprintf(cmd, sizeof cmd, "cd %s && timeout 180 %s build %s 2>/dev/null",
+	    tmpdir, driver, src);
+	return runwait(cmd);
+}
+
+static int
+run_row(const char *driver, const struct row *r, int seq)
+{
+	char tmpdir[256], src[512], base[64], outbin[768];
+	snprintf(tmpdir, sizeof tmpdir, "/tmp/tan_%d_d_%d", getpid(), seq);
+	snprintf(base,   sizeof base,   "main772");
+	snprintf(src,    sizeof src,    "%s/%s.ww", tmpdir, base);
+	mkdir(tmpdir, 0755);
+	if (write_source(src, r->src) != 0) { cleanup_tmp(tmpdir, base); return -1; }
+	int rc = -1;
+	if (build_via_driver(driver, tmpdir, src) == 0) {
+		snprintf(outbin, sizeof outbin, "%s/%s", tmpdir, base);
+		rc = runwait(outbin);
+	}
+	cleanup_tmp(tmpdir, base);
+	return rc;
+}
+
+/* asm_byte_identical — diff cstage vs wwstage .s. Parallel trees so
+ * ww_ww writing intermediates next to the source doesn't clobber the
+ * cstage .s (CLAUDE.md rule 14 phase split). */
+static int
+asm_byte_identical(const char *cdrv, const char *wdrv,
+    const struct row *r, int seq)
+{
+	char src[512], tdc[256], tdw[256], base[64], cs[512], ws[512];
+	snprintf(tdc, sizeof tdc, "/tmp/tan_%d_c_%d", getpid(), seq);
+	snprintf(tdw, sizeof tdw, "/tmp/tan_%d_w_%d", getpid(), seq);
+	snprintf(base, sizeof base, "main772");
+	mkdir(tdc, 0755);
+	mkdir(tdw, 0755);
+	snprintf(src, sizeof src, "%s/%s.ww", tdc, base);
+	if (write_source(src, r->src) != 0) { cleanup_tmp(tdc, base); cleanup_tmp(tdw, base); return -1; }
+	int rc = -1;
+	if (build_via_driver(cdrv, tdc, src) != 0) goto out;
+	snprintf(cs, sizeof cs, "%s/%s.s", tdc, base);
+
+	snprintf(src, sizeof src, "%s/%s.ww", tdw, base);
+	if (write_source(src, r->src) != 0) goto out;
+	if (build_via_driver(wdrv, tdw, src) != 0) goto out;
+	snprintf(ws, sizeof ws, "%s/%s.s", tdw, base);
+
+	FILE *fc = fopen(cs, "rb");
+	FILE *fw = fopen(ws, "rb");
+	if (fc && fw) {
+		rc = 0;
+		for (;;) {
+			int a = fgetc(fc);
+			int b = fgetc(fw);
+			if (a != b) { rc = -1; break; }
+			if (a == EOF) break;
+		}
+	}
+	if (fc) fclose(fc);
+	if (fw) fclose(fw);
+out:
+	cleanup_tmp(tdc, base);
+	cleanup_tmp(tdw, base);
+	return rc;
+}
+
+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 cdrv[640], wdrv[640];
+	snprintf(cdrv, sizeof cdrv, "%s/ww",    bin);
+	snprintf(wdrv, sizeof wdrv, "%s/ww_ww", bin);
+
+	int n = (int)(sizeof rows / sizeof rows[0]);
+	int total = 0, fail = 0;
+	int wwpresent = (access(wdrv, X_OK) == 0);
+	int seq = 0;
+
+	for (int i = 0; i < n; i++) {
+		if (rows[i].stage_mask & STAGE_CS) {
+			total++;
+			int got = run_row(cdrv, &rows[i], seq++);
+			if (got != rows[i].expected_exit) {
+				fprintf(stderr,
+				    "typeassert_nonident[cstage run][%s]: exit=%d want=%d\n",
+				    rows[i].label, got, rows[i].expected_exit);
+				fail++;
+			}
+		}
+		if (wwpresent && (rows[i].stage_mask & STAGE_WW)) {
+			total++;
+			int got = run_row(wdrv, &rows[i], seq++);
+			if (got != rows[i].expected_exit) {
+				fprintf(stderr,
+				    "typeassert_nonident[wwstage run][%s]: exit=%d want=%d\n",
+				    rows[i].label, got, rows[i].expected_exit);
+				fail++;
+			}
+			total++;
+			if (asm_byte_identical(cdrv, wdrv, &rows[i], seq++) != 0) {
+				fprintf(stderr,
+				    "typeassert_nonident[byte-id][%s]: cstage vs wwstage asm differs\n",
+				    rows[i].label);
+				fail++;
+			}
+		}
+	}
+
+	if (!wwpresent)
+		fprintf(stderr, "typeassert_nonident: skip wwstage (no %s)\n", wdrv);
+
+	if (fail) {
+		fprintf(stderr, "typeassert_nonident: %d/%d fixtures failed\n",
+		    fail, total);
+		return 1;
+	}
+	printf("typeassert_nonident: %d/%d ok\n", total, total);
+	return 0;
+}