w6c+selfhost: cross-module same-leaf type disambiguation via Sym.mod

cmd/wcc/parse.c

@@ -1340,6 +1340,14 @@ parsefile(Parser *p)
 	Node *file = newnode(p->a, N_FILE, pp);
 	Node *head = NULL, *tail = NULL;
 	while (p->cur.kind != TK_EOF) {
+		/* Stamp the lex's current `// MODULE: foo` directive on the
+		 * decl BEFORE parsing. cgen uses this for name-mangling and
+		 * check uses it for cross-module type disambiguation. Capture
+		 * before parsing so the closing `expect(SEMI)` doesn't
+		 * accidentally advance the lexer past the *next* `// MODULE:`
+		 * directive — that would stamp this decl with the next
+		 * module's name. */
+		const char *mod = p->l->module;
 		Node *attrs = parseattrs(p);
 		int exp = accept(p, TK_EXPORT);
 		Node *d = NULL;
@@ -1363,10 +1371,7 @@ parsefile(Parser *p)
 			advance(p);
 			continue;
 		}
-		/* Stamp the lex's current `// MODULE: foo` directive on the
-		 * decl. cgen uses it to mangle non-exported names so two
-		 * modules can each privately define `cstrlen`/`streq`/etc. */
-		if (d != NULL) d->module = p->l->module;
+		if (d != NULL) d->module = mod;
 		if (head == NULL) head = d;
 		else tail->next = d;
 		tail = d;