syntax = "proto3";

package test;

import "google/protobuf/descriptor.proto";

extend google.protobuf.MessageOptions {
    optional Foo foo = 10000;
}

message Foo {
    option (foo).map = {
        key: "a"
        value {
            map [
                {key: "a"},
                {key: "b"}
            ]
            map {
                "my_key": {},
            }
        }
    };

    map<string, Foo> map = 1;
}