Field in type IntrospectionResultData defined incorrectly

[dotansimha]

in TypeScript >=2.7 (since this PR), the definition of type[] and [type] are different.
[type] also enforces a length of 1 for the array, while type[] just enforces the Array type without length.

Related to this PR: (fixed the inner array)
#1763

Actual outcome:
Field types in IntrospectionResultData defined as:

export type IntrospectionResultData = {
  __schema: {
    types: [{
      kind: string;
      name: string;
      possibleTypes: {
        name: string;
      }[];
    }];
  };
};

Intended outcome:

It should be:

export type IntrospectionResultData = {
  __schema: {
    types: {
      kind: string;
      name: string;
      possibleTypes: {
        name: string;
      }[];
    }[];
  };
};

How to reproduce the issue:
Use typescript@2.7.1 and define IntrospectionResultData with more than one type, for example:

const cache = new InMemoryCache({
  fragmentMatcher: new IntrospectionFragmentMatcher({
    introspectionQueryResultData: {
      __schema: {
        types: [{
            kind: 'UNION',
            name: 'A',
            possibleTypes: [
              { name: 'AA' },
              { name: 'AB' },
            ]
          }, {
            kind: 'UNION',
            name: 'B',
            possibleTypes: [
              { name: 'BA' },
              { name: 'BB' }
            ]
          },
        ]
      },
    }
  }),
});

As a temporary workaround, it's possible to add as any to the types array value.

Version

• apollo-client@2.2.2
• apollo-cache-inmemory@1.17