It's a partial review. I will find time for other files soon.

[jordan11210]

          It's a partial review. I will find time for other files soon.

Also, please update these files to have the new type with @oneOf: https://github.com/graphql/graphql-js/blob/e17a0897f67305626c6090ce0174f101b7a96fc4/src/__testUtils__/kitchenSinkSDL.ts

Originally posted by @IvanGoncharov in graphql/graphql-js#3513 (review)