wcc/ww: reject value-less return in a non-void fn (catB-24)

wwstage's checkretassign short-circuited on a value-less `return;`
("skip flagging for now"), so `fn f() i32 = { return; }` built and
RET'd a garbage register. Mirror cstage cmd/wcc/check.c:2428-2439:
the no-value return has type void, then run isassignable(c.fnret,
void) — void→void and void→(T|void) accept, void→i32 is a confident
reject. cstage already rejected; this aligns wwstage's w6c_ww UP.

Regen w6c/wwdump combined.ww (checker embeds in both). Valid-program
codegen unchanged → cs==ww byte-id gate stays green.
This commit is contained in:
2026-06-15 03:52:16 +09:00
parent 6b7de54272
commit d0adfe5aab
5 changed files with 228 additions and 9 deletions

View File

@@ -248,6 +248,7 @@ TESTS = $(BIN)/test_smoke $(BIN)/test_lex $(BIN)/test_parse $(BIN)/test_check \
$(BIN)/test_arr_tagged_elem \
$(BIN)/test_dup_main_reject \
$(BIN)/test_tuple_trailing_comma_reject \
$(BIN)/test_voidless_return_reject \
$(BIN)/test_size_untyped_int \
$(BIN)/test_tagged_staticinit \
$(BIN)/test_arr_infer_len \
@@ -1456,6 +1457,12 @@ $(BIN)/test_tuple_trailing_comma_reject: test/wcc/845_tuple_trailing_comma_rejec
$(LIB)/libwwrt.a | $(BIN)
$(CC) $(CFLAGS) -o $@ $<
$(BIN)/test_voidless_return_reject: test/wcc/846_voidless_return_reject.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_tagged_staticinit: test/wcc/843_tagged_staticinit.c $(BIN)/ww \
$(BIN)/w6c $(BIN)/w6a $(BIN)/w6l \
$(BIN)/ww_ww $(BIN)/w6c_ww $(BIN)/w6a_ww $(BIN)/w6l_ww \

View File

@@ -16253,9 +16253,18 @@ fn checkletassign(c: *checker, n: *node) void = {
fn checkretassign(c: *checker, n: *node) void = {
if (n == nil) { return; };
if (n.lhs == nil) {
// bare `return;` — OK iff fnret is void or a tagged union
// with a void variant. Skip flagging for now; cgen handles
// the void-variant tag synthesis already.
// bare `return;` — mirror cstage cmd/wcc/check.c:2428-2439:
// the value-less return has type void, then type_assignable
// (c.fnret, void). A void fnret or a tagged union carrying a
// void variant accepts; a non-void scalar fnret rejects (the
// value-less return would RET a garbage register). isassignable
// reaches the same verdict (void→void typeeqast; void→tagged via
// the void variant; void→i32 a confident primitive mismatch).
if (c.fnret == nil) { return; };
let vt: *node = mktname(c, "void");
let vconf: bool = false;
let vok: bool = isassignable(c, c.fnret, vt, &vconf);
if (vconf) { if (!vok) { errnotassign(c, c.fnret, vt, "return"); }; };
return;
};
if (c.fnret == nil) { return; };

View File

@@ -5779,9 +5779,18 @@ fn checkletassign(c: *checker, n: *node) void = {
fn checkretassign(c: *checker, n: *node) void = {
if (n == nil) { return; };
if (n.lhs == nil) {
// bare `return;` — OK iff fnret is void or a tagged union
// with a void variant. Skip flagging for now; cgen handles
// the void-variant tag synthesis already.
// bare `return;` — mirror cstage cmd/wcc/check.c:2428-2439:
// the value-less return has type void, then type_assignable
// (c.fnret, void). A void fnret or a tagged union carrying a
// void variant accepts; a non-void scalar fnret rejects (the
// value-less return would RET a garbage register). isassignable
// reaches the same verdict (void→void typeeqast; void→tagged via
// the void variant; void→i32 a confident primitive mismatch).
if (c.fnret == nil) { return; };
let vt: *node = mktname(c, "void");
let vconf: bool = false;
let vok: bool = isassignable(c, c.fnret, vt, &vconf);
if (vconf) { if (!vok) { errnotassign(c, c.fnret, vt, "return"); }; };
return;
};
if (c.fnret == nil) { return; };

View File

@@ -16253,9 +16253,18 @@ fn checkletassign(c: *checker, n: *node) void = {
fn checkretassign(c: *checker, n: *node) void = {
if (n == nil) { return; };
if (n.lhs == nil) {
// bare `return;` — OK iff fnret is void or a tagged union
// with a void variant. Skip flagging for now; cgen handles
// the void-variant tag synthesis already.
// bare `return;` — mirror cstage cmd/wcc/check.c:2428-2439:
// the value-less return has type void, then type_assignable
// (c.fnret, void). A void fnret or a tagged union carrying a
// void variant accepts; a non-void scalar fnret rejects (the
// value-less return would RET a garbage register). isassignable
// reaches the same verdict (void→void typeeqast; void→tagged via
// the void variant; void→i32 a confident primitive mismatch).
if (c.fnret == nil) { return; };
let vt: *node = mktname(c, "void");
let vconf: bool = false;
let vok: bool = isassignable(c, c.fnret, vt, &vconf);
if (vconf) { if (!vok) { errnotassign(c, c.fnret, vt, "return"); }; };
return;
};
if (c.fnret == nil) { return; };

View File

@@ -0,0 +1,185 @@
/*
* 846_voidless_return_reject (catB-24) — cstage and wwstage LOUD-REJECT
* a value-less `return;` in a function whose return type is not void.
*
* `fn f() i32 = { return; }` would RET a garbage value register — a
* common programmer slip. cstage rejects at cmd/wcc/check.c:2428-2439
* (a value-less return has type void, then type_assignable(c->ret,
* void) fails for a non-void scalar). wwstage's checkretassign
* short-circuited on the no-value case ("skip flagging for now"), a
* silent accept. The fix builds a void source type and runs the same
* isassignable verdict: void→void and void→(T|void) accept, void→i32
* is a confident reject.
*
* row | shape | expect
* -----------+-----------------------------+--------
* nonvoid | fn f() i32 = { return; }; | REJECT
* void_ok | fn f() void = { return; }; | BUILD, run 5
* value_ok | fn f() i32 = { return 5; }; | BUILD, run 5
* tagged_ok | fn f() (i32|void) ... return;| BUILD, run 9
*/
#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;
}
static void
outbin(char *dst, size_t n, const char *tmpdir, const char *src)
{
const char *base = strrchr(src, '/');
base = base ? base + 1 : src;
snprintf(dst, n, "%s/%s", tmpdir, base);
char *dot = strrchr(dst, '.');
if (dot && strcmp(dot, ".ww") == 0) *dot = '\0';
}
static int
build_should_fail(const char *driver, const char *label, const char *src,
int i)
{
char s[64], tmpdir[64], cmd[1024], bin[128];
snprintf(s, sizeof s, "/tmp/vret_%d_%d.ww", getpid(), i);
snprintf(tmpdir, sizeof tmpdir, "/tmp/vret_%d_d_%d", getpid(), i);
FILE *f = fopen(s, "wb");
if (!f) return -1;
fputs(src, f);
fclose(f);
mkdir(tmpdir, 0755);
snprintf(cmd, sizeof cmd, "cd %s && %s build %s 2>/dev/null",
tmpdir, driver, s);
int rc = runwait(cmd);
outbin(bin, sizeof bin, tmpdir, s);
unlink(s);
unlink(bin);
rmdir(tmpdir);
if (rc == 0)
fprintf(stderr, "vret[%s][%s]: built ok, expected a reject\n",
driver, label);
return rc == 0 ? -1 : 0;
}
static int
run_build(const char *driver, const char *label, const char *src, int i)
{
char s[64], tmpdir[64], cmd[1024], bin[128];
snprintf(s, sizeof s, "/tmp/vret_ok_%d_%d.ww", getpid(), i);
snprintf(tmpdir, sizeof tmpdir, "/tmp/vret_ok_%d_d_%d", getpid(), i);
FILE *f = fopen(s, "wb");
if (!f) return -1;
fputs(src, f);
fclose(f);
mkdir(tmpdir, 0755);
snprintf(cmd, sizeof cmd, "cd %s && %s build %s 2>/dev/null",
tmpdir, driver, s);
if (runwait(cmd) != 0) {
fprintf(stderr, "vret[%s][%s]: build failed (a valid return "
"must compile)\n", driver, label);
unlink(s); rmdir(tmpdir);
return -1;
}
outbin(bin, sizeof bin, tmpdir, s);
int got = runwait(bin);
unlink(s); unlink(bin); rmdir(tmpdir);
return got;
}
struct rejrow { const char *label; const char *src; };
static const struct rejrow reject_rows[] = {
{ "nonvoid",
"package main;\n"
"fn f() i32 = { return; };\n"
"fn main() i32 = { return f(); };\n" },
};
struct okrow { const char *label; const char *src; int want; };
static const struct okrow ok_rows[] = {
{ "void_ok",
"package main;\n"
"fn f() void = { return; };\n"
"fn main() i32 = { f(); return 5; };\n", 5 },
{ "value_ok",
"package main;\n"
"fn f() i32 = { return 5; };\n"
"fn main() i32 = { return f(); };\n", 5 },
{ "tagged_ok",
"package main;\n"
"fn f(x: i32) (i32 | void) = { if (x > 0) { return x; }; return; };\n"
"fn main() i32 = { match (f(0)) { case let v: i32 => return v; "
"case => return 9; }; };\n", 9 },
};
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);
struct { const char *name; const char *path; int gated; } drivers[] = {
{ "cstage", cdrv, 0 },
{ "wwstage", wdrv, 1 },
{ NULL, NULL, 0 },
};
int nrej = (int)(sizeof reject_rows / sizeof reject_rows[0]);
int nok = (int)(sizeof ok_rows / sizeof ok_rows[0]);
int total = 0, fail = 0;
for (int d = 0; drivers[d].name; d++) {
if (drivers[d].gated && access(drivers[d].path, X_OK) != 0) {
fprintf(stderr, "vret: skip %s (no %s)\n",
drivers[d].name, drivers[d].path);
continue;
}
for (int i = 0; i < nrej; i++) {
total++;
if (build_should_fail(drivers[d].path,
reject_rows[i].label, reject_rows[i].src,
d * 100 + i) != 0)
fail++;
}
for (int i = 0; i < nok; i++) {
total++;
int got = run_build(drivers[d].path, ok_rows[i].label,
ok_rows[i].src, d * 100 + i);
if (got != ok_rows[i].want) {
fprintf(stderr, "vret[%s][%s]: exit=%d want=%d\n",
drivers[d].name, ok_rows[i].label,
got, ok_rows[i].want);
fail++;
}
}
}
if (fail) {
fprintf(stderr, "vret: %d/%d fixtures failed\n", fail, total);
return 1;
}
printf("vret: %d/%d ok\n", total, total);
return 0;
}