wcc: kind-filter type-position name resolution so a value can't shadow a same-named type (#225)

resolve_typename used the kind-blind scope_lookup_prefer, so a same-named value binding (param/let) in a closer scope hid the type it shadowed, wrongly rejecting valid Hare like 'fn f(off: off)'. wwstage already separates type/value namespaces; this aligns the cstage frontend up. New scope_lookup_type skips non-SK_TYPE syms and keeps scanning, preserving same-module preference. Byte-id-neutral: the new branch fires only on the old 'unknown type' error path.

cmd/wcc/check.c

@@ -65,7 +65,9 @@ resolve_typename(Checker *c, Node *n)
 	const char *nm = n->str;
 	Type *bi = lookup_builtin(nm);
 	if (bi) return bi;
-	Sym *s = scope_lookup_prefer(c->cur, c->cur_mod, nm);
+	/* #225: kind-filtered so a same-named value binding (param/let/fn)
+	 * in a closer scope can't hide the type binding it shadows. */
+	Sym *s = scope_lookup_type(c->cur, c->cur_mod, nm);
 	if (s == NULL && nm) {
 		/* module-qualified: io.stream → strip the last dot prefix
 		 * and look up the leaf, filtering on the importing module's

cmd/wcc/sym.c

@@ -116,6 +116,34 @@ scope_lookup_prefer(Scope *s, const char *mod, const char *name)
 	return NULL;
 }
 
+/*
+ * scope_lookup_type — kind-filtered bare-leaf lookup for type position.
+ *
+ * Same FNV bucket + hashnext chain + parent walk and same-module
+ * preference as scope_lookup_prefer, but skips every Sym whose kind
+ * isn't SK_TYPE and KEEPS scanning — so it returns the innermost
+ * SK_TYPE of `name`, looking past a same-named value binding (SK_VAR/
+ * SK_PARAM/SK_FN) that shadows it in a closer scope. ww keeps type and
+ * value namespaces separate (wwstage already does; #225 conformance
+ * gap): a param `off` must not hide the global `type off`.
+ */
+Sym *
+scope_lookup_type(Scope *s, const char *mod, const char *name)
+{
+	for (Scope *p = s; p; p = p->parent) {
+		u64 h = hashstr(name) % p->nbuckets;
+		Sym *fallback = NULL;
+		for (Sym *b = p->buckets[h]; b; b = b->hashnext) {
+			if (b->kind != SK_TYPE) continue;
+			if (strcmp(b->name, name) != 0) continue;
+			if (mod && b->mod && strcmp(b->mod, mod) == 0) return b;
+			if (fallback == NULL) fallback = b;
+		}
+		if (fallback) return fallback;
+	}
+	return NULL;
+}
+
 Sym *
 scope_define(Scope *s, const char *name, Skind k, Type *t, Node *decl)
 {

cmd/wcc/ww.h

@@ -526,6 +526,7 @@ Sym	*scope_lookup(Scope*, const char *name);	/* walk up parents */
 Sym	*scope_lookup_local(Scope*, const char *name);
 Sym	*scope_lookup_in_module(Scope*, const char *mod, const char *name);
 Sym	*scope_lookup_prefer(Scope*, const char *mod, const char *name);
+Sym	*scope_lookup_type(Scope*, const char *mod, const char *name);
 
 /* ---- checker (check.c) -------------------------------------------- */
 typedef struct Checker Checker;