fieldnames can give incorrect generated types

[maapteh]

Describe the bug
fieldnames can give incorrect generated types.

To Reproduce
When i have a 'mutation' field in the type 'BasketMutationResult' i get the following result:

export namespace AddBasketItem {
    export type Variables = {
        item: BasketMutation;
    };

    export type Mutation = {
        __typename?: 'Mutation';

        addBasketItem: Maybe<AddBasketItem>;
    };

    export type AddBasketItem = {
        __typename?: 'BasketMutationResult';

        mutation: Maybe<Mutation>;
    };

    export type Mutation =
        | BasketMutationType.Fragment
        | BasketDeleteType.Fragment;
}

It adds type Mutation twice while the last is not correct.

Expected behavior
Not do this :)

Environment:

• OS: OSX
• Codegen: 0.17.0
• Node: 10

[kamilkisiela]

#1369 should fix it

[maapteh]

super!

[dotansimha]

Fixed in 0.18.0 🎉