using declarations are not allowed at the top level with sourceType: script, which is correct behavior as stated in ES2026.

However, in the case of CommonJS, top-level using may be allowed.
In fact, if you run the following code in Node.js v24.2.0 it will work correctly:

// test.cjs
using x = {
    [Symbol.dispose]() {
        console.log('dispose')
    }
};
console.log(x);

run:

node -v
node test.cjs

output:

v24.2.0
{ Symbol(Symbol.dispose): [Function: [Symbol.dispose]] }
dispose

In order to parse this code, I would like acorn to add the allowTopLevelUsingDeclaration option so that it always allows top-level using declarations.

Related to #1373 (comment)