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wcc: accept NAMED-variant nominal match at tagged→tagged subset (#205)

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The tagged→tagged subset arm walked src's leaves against dst's flat
variant list, so `let r: (size | eof | wrapper) = e` with e: wrapper
REJECTED at cstage's checker — wrapper's leaves (unsupported, underread,
nomem) aren't direct variants of dst. Wwstage's permissive tail
accepted silently but cgen then miscompiled the tag (#199b layout-
extension family, deferred).

Mirror the concrete→tagged fix from #199 (α) at type.c:316: when src is
a NAMED-tagged wrapper and dst has a direct NAMED-tagged variant equal
to src, accept by nominal identity BEFORE the subset loop. Wwstage's
isassignable mirrors the structural insertion before the existing
`*confident = false; return true;` tail (deferred-tightening per #202).
SSoT with `is`/`as` non-recursive variant lookup (#198 family).

Cgen's tag-remap for the wrapper-as-whole case still maps src variants
to dst tag 0 — the wrapped-slot layout for `dst.tag = variant_idx,
dst.payload = src` is #199b future-work. Probe verifies checker-accept
+ runtime exit-clean only; does NOT inspect the resulting variant tag.

Probe 774_tagged_widen_named_variant.c covers 5 rows: bug-repro,
nested-wrapper, pure-leaf subset (regression), concrete-unrelated
rejection (gate), branched callee. Two sibling cgen/checker bugs
surfaced (wwstage cgwidentaggedstorebp ssz<slot_sz pad gap; wwstage
isassignable !void-alias collapse) and documented inline at the
probe-row comment, kept in #202 family.
This commit is contained in:
Hojun-Cho
2026-05-29 06:18:27 +09:00
parent 3f4eeff7ff
commit 487cf91f12
6 changed files with 404 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

7
Makefile
View File

@@ -324,6 +324,7 @@ TESTS = $(BIN)/test_smoke $(BIN)/test_lex $(BIN)/test_parse $(BIN)/test_check \
$(BIN)/test_widen_transitive \
$(BIN)/test_typeassert_nonident \
$(BIN)/test_isas_spread_variant \
$(BIN)/test_tagged_widen_named_variant \
$(BIN)/test_use_promote_alias \
$(BIN)/test_field_signed $(BIN)/test_frame_argcount \
$(BIN)/test_selfhost $(BIN)/test_w6a_ww $(BIN)/test_w6l_ww \
@@ -674,6 +675,12 @@ $(BIN)/test_isas_spread_variant: test/wcc/773_isas_spread_variant.c \
$(LIB)/libwwrt.a | $(BIN)
$(CC) $(CFLAGS) -o $@ $<
$(BIN)/test_tagged_widen_named_variant: test/wcc/774_tagged_widen_named_variant.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 \

14
cmd/wcc/type.c
View File

@@ -326,6 +326,20 @@ type_assignable(Type *dst, Type *src)
}
if (du && du->kind == TY_TAGGED &&
su && su->kind == TY_TAGGED) {
/* #205: NAMED-variant nominal compare BEFORE subset.
* Mirror of the concrete→tagged arm at :316-324 (#199 α).
* When src is a NAMED-tagged wrapper and dst has a direct
* NAMED-tagged variant equal to src, accept by nominal
* identity without recursing into src's variants — those
* are wrapper's leaves, not direct variants of dst, so
* the subset loop below would reject. SSoT with `is`/`as`
* variant lookup (#198 family). */
for (Tparam *dp = du->params; dp; dp = dp->next) {
Type *pu = (dp->type && dp->type->kind == TY_NAMED)
? dp->type->under : dp->type;
if (pu && pu->kind == TY_TAGGED &&
type_eq(dp->type, src)) return 1;
}
for (Tparam *sp = su->params; sp; sp = sp->next) {
int ok = 0;
for (Tparam *dp = du->params; dp; dp = dp->next)

18
selfhost/cmd/w6c/main.combined.ww
View File

@@ -13115,6 +13115,24 @@ fn isassignable(c: *checker, dst: *node, src: *node, confident: *bool) bool = {
// return through another fn with the same shape but possibly
// a different surface spelling.
if (du.kind == nkind.N_TTAGGED && su.kind == nkind.N_TTAGGED) {
// #205: NAMED-variant nominal compare BEFORE permissive
// fallthrough. Mirror of cstage type.c type_assignable
// tagged→tagged arm (#199 α concrete→tagged sibling).
// When src is a NAMED-tagged wrapper and dst has a direct
// NAMED-tagged variant equal to src, accept by nominal
// identity — wrapper's leaves are NOT direct variants of
// dst, so a structural subset walk would reject. SSoT
// with `is`/`as` variant lookup (#198 family).
let v: *node = du.list;
for (v != nil) {
let vu: *node = resolvealias(c, unwrapbang(v));
if (vu != nil) {
if (vu.kind == nkind.N_TTAGGED) {
if (typeeqast(v, src)) { return true; };
};
};
v = v.next;
};
*confident = false;
return true;
};

18
selfhost/cmd/wcc/check.ww
View File

@@ -3085,6 +3085,24 @@ fn isassignable(c: *checker, dst: *node, src: *node, confident: *bool) bool = {
// return through another fn with the same shape but possibly
// a different surface spelling.
if (du.kind == nkind.N_TTAGGED && su.kind == nkind.N_TTAGGED) {
// #205: NAMED-variant nominal compare BEFORE permissive
// fallthrough. Mirror of cstage type.c type_assignable
// tagged→tagged arm (#199 α concrete→tagged sibling).
// When src is a NAMED-tagged wrapper and dst has a direct
// NAMED-tagged variant equal to src, accept by nominal
// identity — wrapper's leaves are NOT direct variants of
// dst, so a structural subset walk would reject. SSoT
// with `is`/`as` variant lookup (#198 family).
let v: *node = du.list;
for (v != nil) {
let vu: *node = resolvealias(c, unwrapbang(v));
if (vu != nil) {
if (vu.kind == nkind.N_TTAGGED) {
if (typeeqast(v, src)) { return true; };
};
};
v = v.next;
};
*confident = false;
return true;
};

18
selfhost/cmd/wwdump/main.combined.ww
View File

@@ -13115,6 +13115,24 @@ fn isassignable(c: *checker, dst: *node, src: *node, confident: *bool) bool = {
// return through another fn with the same shape but possibly
// a different surface spelling.
if (du.kind == nkind.N_TTAGGED && su.kind == nkind.N_TTAGGED) {
// #205: NAMED-variant nominal compare BEFORE permissive
// fallthrough. Mirror of cstage type.c type_assignable
// tagged→tagged arm (#199 α concrete→tagged sibling).
// When src is a NAMED-tagged wrapper and dst has a direct
// NAMED-tagged variant equal to src, accept by nominal
// identity — wrapper's leaves are NOT direct variants of
// dst, so a structural subset walk would reject. SSoT
// with `is`/`as` variant lookup (#198 family).
let v: *node = du.list;
for (v != nil) {
let vu: *node = resolvealias(c, unwrapbang(v));
if (vu != nil) {
if (vu.kind == nkind.N_TTAGGED) {
if (typeeqast(v, src)) { return true; };
};
};
v = v.next;
};
*confident = false;
return true;
};

329
test/wcc/774_tagged_widen_named_variant.c Normal file
View File

@@ -0,0 +1,329 @@
/*
* 774_tagged_widen_named_variant — project #205: cstage type_assignable +
* wwstage isassignable tagged→tagged arm misses NAMED-variant nominal
* match. Before the fix, `let e: wrapper = u; let r: (size|eof|wrapper) = e;`
* REJECTED at cstage's checker (wwstage accepted permissively but cgen
* silently miscompiled — separate fold via #199b). The subset loop
* walked wrapper's leaves (unsupported, underread, nomem) against dst
* (size, eof, wrapper) and found none → return 0.
*
* Fix (cmd/wcc/type.c:327 + selfhost/cmd/wcc/check.ww:3087): insert a
* NAMED-variant nominal compare BEFORE the subset loop in the
* tagged→tagged arm. When src is a NAMED-tagged wrapper and dst has a
* direct NAMED-tagged variant equal to src, accept by nominal identity.
* Mirrors the concrete→tagged arm at type.c:316 (#199 α). SSoT with
* `is`/`as` non-recursive variant lookup (#198 family). Wwstage mirrors
* the structural insertion; the existing permissive `*confident = false;
* return true;` tail is preserved (deferred-tightening per #202).
*
* Cgen's tag-remap for the wrapper-as-whole case still maps src
* variants to dst tag 0 (cg_widen_tag_remap walks per-variant); the
* wrapped-slot layout for `dst.tag = variant_idx, dst.payload = src`
* is the deferred #199b future-work. Probes verify checker-accept +
* runtime exit-clean only; they do NOT inspect the resulting variant
* tag of the widen target.
*
* Coverage (5 rows):
* 1. accept_wrapper_variant — BUG-REPRO. `let e: wrapper = u;
* return e;` where return type contains wrapper as direct NAMED
* variant. MUST now ACCEPT + run.
* 2. accept_nested_wrapper — two layers of NAMED-tagged wrap:
* `inner -> outer -> (size|outer)`. Each widen exercises the
* tagged→tagged NAMED nominal compare.
* 3. accept_pure_leaf_subset — REGRESSION GATE. Tagged→tagged
* where every src variant is directly in dst (no wrapper). The
* classic subset path — must keep working.
* 4. reject_concrete_unrelated — REJECTION GATE. Concrete `a` into
* `(b|c)` where a is NOT in dst. Verifies the fix didn't widen
* the concrete→tagged arm's discipline (#199 α stays intact).
* 5. branched_callee_widen — fn returns (size|eof|wrapper)
* from one of two paths (the wrapper-widen and a flat scalar
* variant). Verifies branched runtime, not just constant-fold.
*
* Per-row gates: cstage compile + runtime, wwstage compile + runtime,
* cs.s == ww.s byte-identical (rule-10). Row 4 uses EXPECT_REJECT to
* indicate "build must fail" — driver invocation returns non-zero.
*/
#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
#define EXPECT_REJECT (-2)
struct row {
const char *label;
const char *src;
int expected_exit; /* EXPECT_REJECT means build must fail */
int stage_mask;
int byte_id; /* run cs.s == ww.s diff (works rows only) */
};
static const struct row rows[] = {
{ "accept_wrapper_variant",
"package main;\n"
"type unsupported = !void;\n"
"type underread = !i32;\n"
"type nomem = !void;\n"
"type wrapper = !(unsupported | underread | nomem);\n"
"type eof = void;\n"
"fn f() (size | eof | wrapper) = {\n"
" let u: unsupported;\n"
" let e: wrapper = u;\n"
" return e;\n"
"};\n"
"export fn main() i32 = { let r = f(); return 41; };\n",
41,
STAGE_CS | STAGE_WW, 1 },
{ "accept_nested_wrapper",
"package main;\n"
"type ax = !void;\n"
"type inner = !(ax);\n"
"type outer = !(inner);\n"
"fn f() (size | outer) = {\n"
" let a: ax;\n"
" let i: inner = a;\n"
" let o: outer = i;\n"
" return o;\n"
"};\n"
"export fn main() i32 = { let r = f(); return 42; };\n",
42,
STAGE_CS | STAGE_WW, 1 },
/* Row 3 dst uses an all-!void variant set (8B slot, tag-only) to
* keep ssz == slot_sz at cgwidentaggedstorebp. A wider dst
* (e.g. `(ax|bx|size)`) hits a pre-existing wwstage cgen gap: the
* call-ABI branch unconditionally stores DX/CX/R8 at write_off+8
* when slot_sz > 8, ignoring src ssz, while cstage zero-pads when
* ssz < sz (cmd/w6c/cgen.c:1788-1795 vs selfhost/cmd/wcc/cgenutil.ww
* cgwidentaggedstorebp:2680-2700). Sibling to #202 (wwstage
* cgen-side asymmetry); deferred per #199b layout family. */
{ "accept_pure_leaf_subset",
"package main;\n"
"type ax = !void;\n"
"type bx = !void;\n"
"type cx = !void;\n"
"fn small() (ax | bx) = { let u: ax; return u; };\n"
"export fn main() i32 = {\n"
" let r: (ax | bx | cx) = small();\n"
" return 43;\n"
"};\n",
43,
STAGE_CS | STAGE_WW, 1 },
/* Row 4 uses payload-bearing aliases so wwstage's primitive-mismatch
* arm fires confidently — three !void aliases all collapse to "void"
* via unwrapbang + resolvealias and wwstage falls through to its
* permissive tail (#202 family, deferred). The payload axis (i32
* vs i64 vs f64) splits the underlying primitives so both stages
* reject under the concrete→tagged arm. */
{ "reject_concrete_unrelated",
"package main;\n"
"type ax = !i32;\n"
"type bx = !i64;\n"
"type cx = !f64;\n"
"export fn main() i32 = {\n"
" let u: ax;\n"
" let r: (bx | cx) = u;\n"
" return 0;\n"
"};\n",
EXPECT_REJECT,
STAGE_CS | STAGE_WW, 0 },
{ "branched_callee_widen",
"package main;\n"
"type unsupported = !void;\n"
"type wrapper = !(unsupported);\n"
"type eof = void;\n"
"fn pick(b: bool) (size | eof | wrapper) = {\n"
" if (b) {\n"
" let u: unsupported;\n"
" let e: wrapper = u;\n"
" return e;\n"
" };\n"
" return 50: size;\n"
"};\n"
"export fn main() i32 = {\n"
" let r1 = pick(true);\n"
" let r2 = pick(false);\n"
" return 45;\n"
"};\n",
45,
STAGE_CS | STAGE_WW, 1 },
};
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/wt_%d_d_%d", getpid(), seq);
snprintf(src, sizeof src, "%s/main774.ww", tmpdir);
snprintf(base, sizeof base, "main774");
mkdir(tmpdir, 0755);
if (write_source(src, r->src) != 0) {
cleanup_tmp(tmpdir, base);
return -1;
}
int rc;
int br = build_via_driver(driver, tmpdir, src);
if (r->expected_exit == EXPECT_REJECT) {
rc = (br != 0) ? r->expected_exit : 0;
} else if (br == 0) {
snprintf(outbin, sizeof outbin, "%s/%s", tmpdir, base);
rc = runwait(outbin);
} else {
rc = -1;
}
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/wt_%d_c_%d", getpid(), seq);
snprintf(tdw, sizeof tdw, "/tmp/wt_%d_w_%d", getpid(), seq);
snprintf(base, sizeof base, "main774");
mkdir(tdc, 0755);
mkdir(tdw, 0755);
snprintf(src, sizeof src, "%s/main774.ww", tdc);
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/main774.ww", tdw);
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,
"tagged_widen_named_variant[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,
"tagged_widen_named_variant[wwstage run][%s]: exit=%d want=%d\n",
rows[i].label, got, rows[i].expected_exit);
fail++;
}
if (rows[i].byte_id) {
total++;
if (asm_byte_identical(cdrv, wdrv, &rows[i], seq++) != 0) {
fprintf(stderr,
"tagged_widen_named_variant[byte-id][%s]: cstage vs wwstage asm differs\n",
rows[i].label);
fail++;
}
}
}
}
if (!wwpresent)
fprintf(stderr, "tagged_widen_named_variant: skip wwstage (no %s)\n", wdrv);
if (fail) {
fprintf(stderr, "tagged_widen_named_variant: %d/%d fixtures failed\n",
fail, total);
return 1;
}
printf("tagged_widen_named_variant: %d/%d ok\n", total, total);
return 0;
}