declare namespace WXWebAssembly {
    interface Instance {
        readonly exports: Exports
    }

    function instantiate(
        path: string,
        importObject?: Imports
    ): Promise<Instance>
}

实际返回的是：

lifetimes: {
    async created() {
        WXWebAssembly.instantiate('/wasm/img2webp_wasm_bg.wasm.br', IMPORTS).then(r => {
            console.log(r) // {"instance":{},"module":{}}
        })
    }
}

实际返回值与签名不符。