ww imports: reject init bindings before recovery

cmd/wcc/check.c

@@ -2907,6 +2907,25 @@ decl_mod(Node *file, Node *d)
 	return NULL;
 }
 
+static int
+invalid_init_import(Node *u)
+{
+	return u != NULL && u->kind == N_USE && !u->useblank
+	    && u->str != NULL && strcmp(u->str, "init") == 0;
+}
+
+static Pos
+import_binding_pos(Node *u)
+{
+	Pos p = u->pos;
+	if (u->usefile != NULL) {
+		p.file = u->usefile;
+		p.line = u->useline;
+		p.col = u->usecol;
+	}
+	return p;
+}
+
 /*
  * use_path — map a source-file default qualifier (the imported package's
  * declared name) to the full canonical import path it binds, for
@@ -2932,7 +2951,7 @@ find_use_path(Node *file, const char *curmod, int source, const char *alias,
 		if (strcmp(alias, leaf) == 0) return curmod;
 	}
 	for (Node *u = file->list; u; u = u->next) {
-		if (u->kind != N_USE || u->str == NULL
+		if (u->kind != N_USE || u->str == NULL || invalid_init_import(u)
 		    || u->sourceid != source || strcmp(u->str, alias) != 0)
 			continue;
 		const char *p = u->usepath ? u->usepath : u->str;
@@ -3960,6 +3979,19 @@ check_import_alt(Node *d, const char *name)
 	    d->pos.file ? d->pos.file : "?", d->pos.line, d->pos.col, name);
 }
 
+/* Pinned Go 1.26.5 types2 rejects an effective import binding named init and
+ * immediately continues before creating its PkgName. Diagnose every resolved
+ * occurrence at the first import-spec token, then keep it out of all binding
+ * recovery below while retaining the real loader-owned dependency edge. */
+static void
+reject_init_imports(Checker *c, Node *file)
+{
+	for (Node *u = file->list; u; u = u->next)
+		if (invalid_init_import(u))
+			err(c, import_binding_pos(u),
+			    "cannot import package as init - init must be a func");
+}
+
 /* Go's default import binding lives in the importing file's scope. Reject
  * only another binding in that same source section; equal names in sibling
  * files are independent even though their canonical edges are package-wide. */
@@ -3968,11 +4000,11 @@ check_import_redeclarations(Checker *c, Node *file)
 {
 	if (!c->sep_mode) return;
 	for (Node *u = file->list; u; u = u->next) {
-		if (u->kind != N_USE || u->useblank
+		if (u->kind != N_USE || u->useblank || invalid_init_import(u)
 		    || u->imported || u->str == NULL)
 			continue;
 		for (Node *v = file->list; v != u; v = v->next) {
-			if (v->kind != N_USE || v->useblank
+			if (v->kind != N_USE || v->useblank || invalid_init_import(v)
 			    || v->imported || v->str == NULL
 			    || v->sourceid != u->sourceid)
 				continue;
@@ -3994,7 +4026,7 @@ check_import_usage_and_collisions(Checker *c, Node *file)
 {
 	if (!c->sep_mode) return;
 	for (Node *u = file->list; u; u = u->next) {
-		if (u->kind != N_USE || u->useblank
+		if (u->kind != N_USE || u->useblank || invalid_init_import(u)
 		    || u->imported || u->used || u->str == NULL)
 			continue;
 		const char *path = u->usesource ? u->usesource
@@ -4011,7 +4043,7 @@ check_import_usage_and_collisions(Checker *c, Node *file)
 		if (d->imported || !top_decl_kind(d) || d->str == NULL)
 			continue;
 		for (Node *u = file->list; u; u = u->next) {
-			if (u->kind != N_USE || u->useblank
+			if (u->kind != N_USE || u->useblank || invalid_init_import(u)
 			    || u->imported || u->str == NULL
 			    || strcmp(d->str, u->str) != 0)
 				continue;
@@ -4078,6 +4110,7 @@ check_file(Checker *c, Node *file)
 			file->list = usenode;
 		}
 	}
+	reject_init_imports(c, file);
 	reject_nonfunction_main_decls(c, file);
 	mark_import_uses(c, file);
 	check_import_redeclarations(c, file);
@@ -4106,10 +4139,8 @@ check_file(Checker *c, Node *file)
 				    "'%s' cannot import itself", owner);
 			if (d->useblank)
 				continue;
-			if (d->str != NULL && strcmp(d->str, "init") == 0) {
-				err(c, d->pos, "cannot import package as init - init must be a func");
+			if (invalid_init_import(d))
 				continue;
-			}
 			Sym *prev = scope_lookup_local(c->cur, d->str);
 			if (prev != NULL) {
 				/* Self-import: the driver concatenates the

cmd/wcc/parse.c

@@ -1323,6 +1323,12 @@ parseuse(Parser *p)
 	Pos pp = p->cur.pos;
 	expect(p, TK_USE);
 	Node *n = newnode(p->a, N_USE, pp);
+	/* Keep n->pos at the import keyword for structural diagnostics. Go's
+	 * import declaration position is the first spec token: the explicit alias
+	 * when present, otherwise the path. */
+	n->usefile = p->cur.pos.file;
+	n->useline = p->cur.pos.line;
+	n->usecol = p->cur.pos.col;
 	const char *alias = NULL;
 	const char *first;
 	if (p->cur.kind == TK_UNDER) {

cmd/wcc/ww.h

@@ -349,6 +349,10 @@ struct Node {
 	const char	*usepath;	/* N_USE: canonical, vendor-expanded identity;
 					 * initially equal to `usesource`. */
 	const char	*usealias;	/* N_USE: explicit file-local alias, or NULL. */
+	const char	*usefile;	/* N_USE: first import-spec token position;
+					 * alias when explicit, path otherwise. */
+	int		useline;
+	int		usecol;
 	const char	*usepkgname;	/* N_USE: imported declared package name,
 					 * independent of the visible binding in `str`. */
 	int		useblank;	/* N_USE: `_` spelling; no source binding. */