google.protobuf.Struct is invalid when generated with useMapType=true

[roboslone]

Generated code:

  wrap(object: { [key: string]: any } | undefined): Struct {
    const struct = createBaseStruct();
    if (object !== undefined) {
      Object.keys(object).forEach((key) => {
        struct.fields[key] = object[key]; // <----------------
      });
    }
    return struct;
  },

  unwrap(message: Struct): { [key: string]: any } {
    const object: { [key: string]: any } = {};
    Object.keys(message.fields).forEach((key) => {
      object[key] = message.fields[key]; // <----------------
    });
    return object;
  },

google/protobuf/struct.ts:163:9 - error TS7052: Element implicitly has an 'any' type because type 'Map<string, any>' has no index signature. Did you mean to call 'struct.fields.set'?

163         struct.fields[key] = object[key];
            ~~~~~~~~~~~~~~~~~~

google/protobuf/struct.ts:172:21 - error TS7052: Element implicitly has an 'any' type because type 'Map<string, any>' has no index signature. Did you mean to call 'message.fields.get'?

172       object[key] = message.fields[key];
                        ~~~~~~~~~~~~~~~~~~~

[stephenh]

Fixed by #740, thanks @roboslone !